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The effect of locally administered PGF2α on the contractility of the nonpregnant human uterus in vivo
THE EFFECT
OF LOCALLY ADMINISTERED
CONTRACTILITY
PGF2o
ON THE
OF THE NONPREGNANT HUMAN UTERUS IN VIVO J. N. Martin x) and M. Bygdeman
Department Karolinska
of Obstetrics and Gynecology Hospital, Stockholm, Sweden
ABSTRACT The effect of locally administered prostaglandin F2a on the sensitivity and reactivity of the nonpregnant human uterus durmg the menstrual cycle was studied. An increase in uterine contractility in response to as little as 1.0 /.+gPGF2o could be observed in all patients during both the early and late portions of the menstrual cycle, but at the time of ovulation a marked decrease in sensitivity was noted. Endcgenous prostaglandin normally occurs in the secretory endometrium in levels compatible with the amount of exogenous prostaglandin which elicited increased uterine activity. These findings support the hypothesis that plays an important physiological role in the cyclical regulation PGF2a! of uterine motility during the human menstrual cycle.
ACKNOWLEDGEMENT This investigation was supported by a grant from the Swedish Medic81 Research Council (grant 2028) and the Prostaglandin Task Force in the WHO Expanded Program. The authors acknowledge their indebtedness to A. Clapsakiz, M. Ewerlijf and I. Wanrud of the Clinical Research Unit nursing staff and to Ms. L. Lundgren for her assistance in the typing of the manuscript. The authors also wish to thank P. Eneroth, director of the Hormone Laboratory, for his assistance in the determination of serum progesterone levels.
x) WHO Clinical and Gynecology,
Research Fellow on leave from the Dept. of Obstetrics North Carolina Memorial Hospital, Chapel Hill, N. C.
Accepted January 14
PROSTAGLANDINS FEBRUARY
1975
VOL. 9 NO. 2
245
PROSTAGLANDINS
INTRODUCTION fn recent years there have been several reports on the motility and reactivity patterns of the nonpregnant human uterus in response to systemic prostaglandin administration (l-4). With the exception of Embrey’s limited work, no investigation has been made of the effect of intrauterine PGF instillation (5). Morever, the correlation between the effect of prostag ?”andin with various phases of the menstrual cycle has been conspicuously lacking. Earlier observations based mainly on estimations by biological methods have indicated that the endogenous endometrial production of PGF is increased progressively during the secretory phase of the men&r& cycle and that the concentration of PGF in menstrual fluid seems to be substantially higher in patients with ismary dysmenorrhea (6). It follows that endogenous prostaglandins may be involved in the regulation of uterine contractility especially during menstruation. The results obtained from the systemic intravenous administration of prostaglandin is difficult to interpret with regard to uterine sensitivity since the amount of compound reaching the uterus is not only small but variable (7,8). The aim of the present study was to investigate the sensitivity and reactivity of the nonpregnant human uterus to the intrauterine administration of PGF 2~ during the various phases of the menstrual cycle.
PATIENTS AND MJZTHODS Six women volunteered for the study. All patients were nulliparous, using no contraceptive agents, had regular menstrual cycles and were found to be healthy with normal gynecological examinations. The timing of ovulation during the cycle under investigation was determined by daily measurements of basal body temperature and analysis of serum progesterone at the time of recording. Reference to the time of recording in this paper is based upon the number of days before (-) or after (+) the estimated date of ovulation. There were 26 recording sessions for the six patients, 21 for study purposes and 5 controls. All patients were recorded at least once during the proliferative and secretory portions of the cycle as well as around the expected time of ovulation. Uterine contractility was recorded by means of a flaccid microballoon (0.1 ml volume capacity) tied to a polyethylene catheter and connected to a Statham pressure transducer and a Grass polygraph. The closed system was carefully calibrated in mm Hg before recording. At the patient’s first visit the direction and length of the cervico-uterine canal was determined by sounding the uterus. The microballoon then was passed gently through the endocervical canal at least one cm beyond the internal OS. The catheter was secured in place by wedging several gauze planchets against the cervix prior to removal of the speculum. Following this the patient was placed in the supine position and maintained there for the duration of the recording. 246
FEBRUARY
1975
VOL. 9 NO. 2
PROSTAGLANDINS
Baseline. uterine activity was recorded prostaglandin administration.
for at least 20 minutes prior to
Increasing amounts of PGF20 (1 4 per 0.2 ml normal saline solution prepared immediately before testing) were administered into the uterine cavity via a thin polyethylene catheter tied to the main recording system. The time interval between injections normally allowed uterine contractility to return to resting levels. Uterine stimulation was considered significant whenever basal tonus was elevated more then five mm Hg or when there occurred an obvious increase in amplitude and/or frequency of contractions. The sixth patient acted as control during 5 recording sessions and received saline instead of PGF 2~ injected into the uterus in amounts up to 1.6 ml.
RESULTS The nonpregnant human uterus responds w;th variable sensitivity to the intrauterine administration of PGFZa during different phases of the menstrual cycle. An increase in uterine contractility could be observed in all patients during both the early and late portions of the menstrual cycle, but at the time of ovulation a marked decrease in sensitivity was noted. It is notable that the response to injections was never one of inhibition. If a dose exceeding threshold level were administered, the uterine response was not always noted to be constantly or proportionately increased. Also, the suggestion of a “refractory period” following an obvious uterine response was observed in several -recordings made late in the secretory phase. Recordings from patient I. S. on the days -9, -3, and 0 are illustrated in figure 1. Spontaneous uterine contractility during the early proliferative phase was characterized by a low amplitude, moderately frequent irregular pattern. On day -3, three days prior to ovulation, the uterine contractility was essentially unchanged. On the day of ovulation, however, the uterine motility pattern was characterized by low amplitude, high frequency contractions. During the early proliferative phase, intrauterine instillation of one ccg of induced uterine stimulation characterized by gradual elevation in PGF 2o uterme tonus which was sustained for 20 minutes. The stimulation was more pronounced with larger doses of the compound. Three days prior to ovulation the injection of 2. 0 &g PGF 2ohstill elicited a significantly increased elevation in uterine tonus, w ile on the day of ovulation doses up to 7.5 &g of PGF2c did not elicit any notable response.
FEBRUARY
1975
VOL. 9 NO. 2
247
PROSTAGLANDINS
mm Hg
50 day-9
0 50
I 1 1
1 pg PGF2a
2 pg PGF2a
3 pg PGFp
5pg
day - 03
50
day
I
PGF,a
7.5 pg PGF2a
I
t
00
10 min.
Figure 1. Uterine recording from patient I. 8.. showing the uterine response to locally administered on day 9 before ovulation (top), day 3 PGF2ck! before ovulation (middle) and on the day of ovulation (bottom).
Spontaneous uterine activity during the secretory phase evolved towards menstruation into Lower frequency, higher amplitude contractions resembling those seen late in the prelabor phase of term pregnancy (figure 2). Well into the secretory phase of the menstrual cycle (day +4 in patient K. B. 4 days after ovulation), the response of the nonpregnant human uterus to returned to its pre-ovulatory level of sensitivity. ;;~;;p~$$~.r;u~~~ emonstrates the development of increased contractional amplitude and uterine tone in patient K. B. following the intrauterine injection of 2.0 and 4.0 M FGF in 0.4 and 0.8 ml of solution respectively. Mild discomfort was rep&&d by the patient following the latter injection. A similarly high level of sensitivity persisted until the onset of menstrual bleeding. On day +9 (day 26 of the menstrual cycle) patient K. B. responded to 4 pg PGF20 (Lower part of figure 2) while patient C. L. and K. L. responded to as little as 2.0 and 3.0 ng. Typically the uterine response was one of increased tone with increased contractional frequency. The threshold values
24%
FEBRUARY
1975
VOL. 9 NO. 2
PROSTAGLANDINS
1pg PGF2a
2 pg PGF*cY
4 pg PGFza
I
10 min. Figure 2. Uterine recordings from patient K. B. showing the uterine response to locally administered PGF on the fourth (top) and ninth (bottom) days after%vutation.
from all 5 patients studied are summarized in figure 3. The intrauterine injection of saline at various phases of the menstrual cycle in amounts corresponding to the volumes of prostaglandin administered did not cause any uterine response. f
%3. 5 7_ Y6 w 5.
A
E z
0
.
t .
21.
.
A
8 b0 -I 3. 0 5
A
. .
. -12 -1’2 -lb
.
.
. -8
-b
-Z
DAYS BE!=ORE AND AFTER
. .
-2
‘0
.
.
.
i2 +L 45 th +io tl2 tfb
DAY OF OVULATION
( DAY 0)
Figure 3. Summary of threshold values for ~;L;e$$u~;;~&~;(q~
;;t;,“,ttz;;t;of
ovutation. The symbol (4) denotes the highest dose of prostaglandin which was administered without effect .
FEBRUARY
1975
VOL.
9 NO. 2
249
PROSTAGLANDINS
DISCUSSION The flaccid microballon technique for the recording of uterine contractility as described by several investigators has been shown to be as efficacious as the open-end method (9,10). The absence of problems involving obstructive uterine secretions which might require continuous flow systems with the open-end catheter and its inert suitability in connection with the study of effects following the concomitant administration of liquid agents such as constitute important merits of the flaccid microballoon technique PGF in th@study. Variations of inherent uterine contractility throughout the menstrual cycles of the six patients was comparable to the characteristic patterns described previously by others (10-X). In the proliferative phase the basic pattern was characterized by frequent moderate contractions of short duration, while around the time of ovulation contractional intensity was somewhat diminished and more regular. Into the secretory phase less frequent, larger and more irregular “pre-labor” contractions became increasingly predominant. Finally, during early menstruation, the contractions were generally regular, “labor-like” and measured up to 225-250 mm Hg in intensity. Notwithstanding that all recordings exhibited features of these general patterns, there was wide variation noted between patients. The present study demonstrates that the nonpregnant human uterus responds differentially to locally administered PGF2,, according to the time of ovulation and phase of the menstrual cycle. A relative insensitivity to natural PGF was noted in all patients both in the immediate pre- and post-ovulato?y period. As much as 7.5-8.0 ).+Iof the compound failed to stimulate the uterus at this time, in contrast to the stimulation observed with as little as 1.0-2.0 &g during other parts of the menstrual cycle. A significant increase in sensitivity during the immediate premenstrual period was not observed. The impossibility of objectively evaluating the into variable amounts of menstrual fluid during early injection of PGF 2oiuded investigations of this portion of the menstrual menstruation prec cycle. The intrauterine administration of saline to control patient I. P. , in volumes equivalent to the prostaglandin-containing solutions given to the other patients in these studies, failed to elicit any difference in uterine contractility at any time during the menstrual cycle. on the nonpregnant human Previous in vivo studies of the effect of PGF uterus have utilized single intravenous injec E” ions or infusions of the compound (l-4). Invariably an increase in uterine contractility was caused by single i. v. doses exceeding a threshold level of approximately 50 & (l-2). Such systemic studies cannot be applied to an understanding of either local uterine physiological events or variable uterine sensitivity since the amount of compound eventually reaching the uterus must be small and variable. Approximately 90% of an intravenously injected amount of prostaglandin will be inactivated during a single passage through the lungs (7). It has also
FEBRUARY
1975
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9 NO. 2
PROSTAGLANDINS
in patients receiving an intrabeen shown that blood levels of PGF venous infusion of 75 pg/min for 10 i?ours ranged from 1.2 to 5.7 ng/ml (8). administration is by Embrey as The only report of intrauterine PGF quoted by Pickles aal. (5). Embre$ound that as little as 0.5 /*g PGF stimulated increased uterine contractility in two patients on days 24 ando 26 cf their menstrual cycles. Such a finding is compatible with the present results. The recording by Embrey was made, however, following a dilatation and curettage procedure which might have influenced the results. No further intrauterine studies investigating PGF sensitivity during the remainder of the menstrual cycle to our know i!age have appeared in the literature. Green and Hagenfeldt recently used the gas chromatography-mass spectrometry method to measure PGF and 15-keto-13,14-dihydro-PGF levels in the human endometriu%! during the menstrual cycle (16). %eir careful investigation showed that 15-keto-13,14-dihydro-PGF 2p’. the was present in the endome rmm in major serum metabolite of PGF high concentrations (55-1940 ngy$‘on day 22. At the time of ovulation, however, tissue levels of the compound were significantly lower and in most cases undetectable. The endometrial content of prostaglandin F20 followed a similar pattern -- higher concentrations of the parent compound being measured during the secretory phase (130-8280 rig/g)) than at the time of ovulation (65-5790 ng/g). At least during the late secretory phase such endogenous levels correspond to the exogenous amounts of PGF2e which elicited uterine reactivity when administered to the patients in the present study. These findings are compatible with the earlier work of Pickles et al. who found that (a) the primary prostaglandins are present in the human endometrium during both the proliferative and the secretory phase of the menstrual cycle; (b) endometrial tissue from the secretory phase has a higher content of PGF2o with an increased PGF:PGE ratio; and (c) menstrual fluid contains about 10 times more PGF 2a, than is found in secretory endometrial curettings (6). The present results and the above findings support the hypotheses that PGF plays an important physiological role in the cyclical regulation of uter&% motility during the menstrual cycle and that an overproduction of this compound during menstruation may be an important factor responsible not only for the increased myometrial activity seen but also for the pain of primary dysmenorrhea. Studies under way by Lundstrom et al. have shown that the treatment of some dysmenorrheic patients with prostaglandin biosynthetic inhibitor indomethacin has resulted in impressive symptomatic improvement and a reduction in recorded uterine tonus level (17). Midcycle, periovulatory insensitivity to locally administered PGF20 corresponds to the highest level of estrogen achieved during the menstrual FEBRUARY
1975
VOL.
9 NO. 2
PROSTAGLANDINS
cycle. Such an interrelationship suggests that the myometrial reactivity to PGF may be under hormonal control similar to what has been report Zfr for vasopressin (18). A periovulatory decrease of inherent uterine motility may play a physioLogical role in sperm migration and fertilization. Since semen contains predominantly primary prostaglandin of the E-type as well as some F, investigation of PGE and its effect upon the nonpregnant human uterus during the menstrua?cycle will be of interest in helping to elucidate the role of prostaglandins in reproductive physiology. Such work is under way in our laboratory.
REFERENCES 1.
Roth-Brandel, U. , M. Bygdeman and N. Wiqvist. Effect of intravenous administration of prostaglandin E1 and F2o on the contractility of the nonpregnant human uterus in vlvo. Acta Obstet. Gynec. Stand. 49, Suppl. 5:19-25, 1970.
2.
Wiqvist, N. , U. Roth-Brandel and M. Bygdeman. The side effect on the nonpregnant human uterus -in of prostaglandin E and F Int. J. Gynei. & Ol%et. 8:165, 1970. m.
3.
Karim, S. M. M. , K. Hillier, K. Somers and R. R. Trusell. The effects of prostaglandins E2 and F20 administered by different routes on uterine activity and the cardiovascular system in pregnant and nonpregnant women. J. Obstet. Gynaec. Brit. Commonw. 78: 172-179, 1971.
4.
Coutinho, E. M. and H. S. Maia. The contractile response of the human uterus, fallopian tubes & ovary to prostaglandins in vivo. Fertil. Steril. 22:539-543, 1971.
5.
Pickles, V. R. , W. J. Hall, P. C. Clegg and T. J. Sullivan. Some experiments on the mechanism of action of prostaglandin of the guinea pig and rat myometrium. In: Endogenous Substances Affecting the Myometrium (eds. V. R. Pickles and R. J. Fitzpatrick), Mem. Sot. Endocrinol. 14:80-103, 1966.
6.
Pickles, V. R. , W. J. Hall, F. A. Best and G. N. Smith. Prostaglandins in endometrium and menstrual fluid from normal and dysmenorrheic subjects. J. Obstet. Gynaec. Brit. Commonw. 72: 185-192, 1965.
7.
Samuelsson, B. , E. Granstrijm, K. Green and M. Hamberg. Metabolism of prostaglandins. Ann. N. Y. Acad. Sci. 180:138, 1971. FEBRUARY
1975
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9 NO. 2
PROSTAGLANDINS
8.
Green, K., F. Beguin, M. Bygdeman, M. Toppozada and N. Wiqvist. Analysis of prostaglandin F and metabolites following intravenous, intraamniotic and v$?$nal administration of prostaglandin F20. In: Prostaglandins in Fertility Control. WHO Conference. Stockholm (eds. S. Bergstrom, K. Green and B. Samuelsson): 189-200, 1972.
9.
Csapo, A. I. and C. R. Pinto-Dantas. The cyclic activity of the nonpregnant human uterus. Fertil. Steril. 17:34-38, 1966.
10.
Coutinho, E. Proceedings International International
11.
Hendricks, C. H. Activity patterns in the nonpregnant human uterus. In: Muscle (eds. E. Daniel, W. Paul, E. M. Kay. and G. Monckton). Pergamon Press, New York: 349-362, 1965.
12.
Hendricks, C. H. Inherent motility patterns and response characteristics in the nonpregnant human uterus. Am. J. Obstet. Gynec. 96:824-843, 1966.
13.
Moawad, A. H. and L. P. Bengtsson. In vivo studies of the motility patterns of the nonpregnant human uterus. Am. J. Obstet. Gynec. 98:1057-1064, 1967.
14.
Cibils, L. A. Contractility of the nonpregnant human uterus. Obstet. Gynec. 30:441-461, 1967.
15.
Hein, P.R. , T. K. A. B. Eskes, L.A. M. Stolte, J. T. Braaksma, J. Janssens and J. M. v.d. Hoek. The influence of steroids on uterine motility in the nonpregnant human uterus. In: Uterine Contraction (ed. J. B. Josimovick), John Wiley & Sons, Inc. : 107-128, 1973.
16.
Green, K. and K. Hagenfeldt. Prostaglandins in the human endometrium: Gas chromatographic-mass spectrometric quantitation before and after IUD insertion. Am. J. Obstet. Gynec. In press 1974.
17.
Lundstrijm,
18.
Coutinho, E. M. and A. C. V. Lopes. Response of the nonpregnant human uterus to vasopressin as an index of ovarian function. Am. J. Obstet. Gynec. 102:479-489, 1968.
FEBRUARY
M. Uterine activity in nonpregnant women. In: of the Eighth International Conference of the Parenthood Federation (eds. Hankinson et al.), Parenthood Federation, London: 432-49, 1967.
V.,
1975
K. Green and N. Wiqvist.
VOL. 9 NO. 2
To be published.
253
OF LOCALLY ADMINISTERED
CONTRACTILITY
PGF2o
ON THE
OF THE NONPREGNANT HUMAN UTERUS IN VIVO J. N. Martin x) and M. Bygdeman
Department Karolinska
of Obstetrics and Gynecology Hospital, Stockholm, Sweden
ABSTRACT The effect of locally administered prostaglandin F2a on the sensitivity and reactivity of the nonpregnant human uterus durmg the menstrual cycle was studied. An increase in uterine contractility in response to as little as 1.0 /.+gPGF2o could be observed in all patients during both the early and late portions of the menstrual cycle, but at the time of ovulation a marked decrease in sensitivity was noted. Endcgenous prostaglandin normally occurs in the secretory endometrium in levels compatible with the amount of exogenous prostaglandin which elicited increased uterine activity. These findings support the hypothesis that plays an important physiological role in the cyclical regulation PGF2a! of uterine motility during the human menstrual cycle.
ACKNOWLEDGEMENT This investigation was supported by a grant from the Swedish Medic81 Research Council (grant 2028) and the Prostaglandin Task Force in the WHO Expanded Program. The authors acknowledge their indebtedness to A. Clapsakiz, M. Ewerlijf and I. Wanrud of the Clinical Research Unit nursing staff and to Ms. L. Lundgren for her assistance in the typing of the manuscript. The authors also wish to thank P. Eneroth, director of the Hormone Laboratory, for his assistance in the determination of serum progesterone levels.
x) WHO Clinical and Gynecology,
Research Fellow on leave from the Dept. of Obstetrics North Carolina Memorial Hospital, Chapel Hill, N. C.
Accepted January 14
PROSTAGLANDINS FEBRUARY
1975
VOL. 9 NO. 2
245
PROSTAGLANDINS
INTRODUCTION fn recent years there have been several reports on the motility and reactivity patterns of the nonpregnant human uterus in response to systemic prostaglandin administration (l-4). With the exception of Embrey’s limited work, no investigation has been made of the effect of intrauterine PGF instillation (5). Morever, the correlation between the effect of prostag ?”andin with various phases of the menstrual cycle has been conspicuously lacking. Earlier observations based mainly on estimations by biological methods have indicated that the endogenous endometrial production of PGF is increased progressively during the secretory phase of the men&r& cycle and that the concentration of PGF in menstrual fluid seems to be substantially higher in patients with ismary dysmenorrhea (6). It follows that endogenous prostaglandins may be involved in the regulation of uterine contractility especially during menstruation. The results obtained from the systemic intravenous administration of prostaglandin is difficult to interpret with regard to uterine sensitivity since the amount of compound reaching the uterus is not only small but variable (7,8). The aim of the present study was to investigate the sensitivity and reactivity of the nonpregnant human uterus to the intrauterine administration of PGF 2~ during the various phases of the menstrual cycle.
PATIENTS AND MJZTHODS Six women volunteered for the study. All patients were nulliparous, using no contraceptive agents, had regular menstrual cycles and were found to be healthy with normal gynecological examinations. The timing of ovulation during the cycle under investigation was determined by daily measurements of basal body temperature and analysis of serum progesterone at the time of recording. Reference to the time of recording in this paper is based upon the number of days before (-) or after (+) the estimated date of ovulation. There were 26 recording sessions for the six patients, 21 for study purposes and 5 controls. All patients were recorded at least once during the proliferative and secretory portions of the cycle as well as around the expected time of ovulation. Uterine contractility was recorded by means of a flaccid microballoon (0.1 ml volume capacity) tied to a polyethylene catheter and connected to a Statham pressure transducer and a Grass polygraph. The closed system was carefully calibrated in mm Hg before recording. At the patient’s first visit the direction and length of the cervico-uterine canal was determined by sounding the uterus. The microballoon then was passed gently through the endocervical canal at least one cm beyond the internal OS. The catheter was secured in place by wedging several gauze planchets against the cervix prior to removal of the speculum. Following this the patient was placed in the supine position and maintained there for the duration of the recording. 246
FEBRUARY
1975
VOL. 9 NO. 2
PROSTAGLANDINS
Baseline. uterine activity was recorded prostaglandin administration.
for at least 20 minutes prior to
Increasing amounts of PGF20 (1 4 per 0.2 ml normal saline solution prepared immediately before testing) were administered into the uterine cavity via a thin polyethylene catheter tied to the main recording system. The time interval between injections normally allowed uterine contractility to return to resting levels. Uterine stimulation was considered significant whenever basal tonus was elevated more then five mm Hg or when there occurred an obvious increase in amplitude and/or frequency of contractions. The sixth patient acted as control during 5 recording sessions and received saline instead of PGF 2~ injected into the uterus in amounts up to 1.6 ml.
RESULTS The nonpregnant human uterus responds w;th variable sensitivity to the intrauterine administration of PGFZa during different phases of the menstrual cycle. An increase in uterine contractility could be observed in all patients during both the early and late portions of the menstrual cycle, but at the time of ovulation a marked decrease in sensitivity was noted. It is notable that the response to injections was never one of inhibition. If a dose exceeding threshold level were administered, the uterine response was not always noted to be constantly or proportionately increased. Also, the suggestion of a “refractory period” following an obvious uterine response was observed in several -recordings made late in the secretory phase. Recordings from patient I. S. on the days -9, -3, and 0 are illustrated in figure 1. Spontaneous uterine contractility during the early proliferative phase was characterized by a low amplitude, moderately frequent irregular pattern. On day -3, three days prior to ovulation, the uterine contractility was essentially unchanged. On the day of ovulation, however, the uterine motility pattern was characterized by low amplitude, high frequency contractions. During the early proliferative phase, intrauterine instillation of one ccg of induced uterine stimulation characterized by gradual elevation in PGF 2o uterme tonus which was sustained for 20 minutes. The stimulation was more pronounced with larger doses of the compound. Three days prior to ovulation the injection of 2. 0 &g PGF 2ohstill elicited a significantly increased elevation in uterine tonus, w ile on the day of ovulation doses up to 7.5 &g of PGF2c did not elicit any notable response.
FEBRUARY
1975
VOL. 9 NO. 2
247
PROSTAGLANDINS
mm Hg
50 day-9
0 50
I 1 1
1 pg PGF2a
2 pg PGF2a
3 pg PGFp
5pg
day - 03
50
day
I
PGF,a
7.5 pg PGF2a
I
t
00
10 min.
Figure 1. Uterine recording from patient I. 8.. showing the uterine response to locally administered on day 9 before ovulation (top), day 3 PGF2ck! before ovulation (middle) and on the day of ovulation (bottom).
Spontaneous uterine activity during the secretory phase evolved towards menstruation into Lower frequency, higher amplitude contractions resembling those seen late in the prelabor phase of term pregnancy (figure 2). Well into the secretory phase of the menstrual cycle (day +4 in patient K. B. 4 days after ovulation), the response of the nonpregnant human uterus to returned to its pre-ovulatory level of sensitivity. ;;~;;p~$$~.r;u~~~ emonstrates the development of increased contractional amplitude and uterine tone in patient K. B. following the intrauterine injection of 2.0 and 4.0 M FGF in 0.4 and 0.8 ml of solution respectively. Mild discomfort was rep&&d by the patient following the latter injection. A similarly high level of sensitivity persisted until the onset of menstrual bleeding. On day +9 (day 26 of the menstrual cycle) patient K. B. responded to 4 pg PGF20 (Lower part of figure 2) while patient C. L. and K. L. responded to as little as 2.0 and 3.0 ng. Typically the uterine response was one of increased tone with increased contractional frequency. The threshold values
24%
FEBRUARY
1975
VOL. 9 NO. 2
PROSTAGLANDINS
1pg PGF2a
2 pg PGF*cY
4 pg PGFza
I
10 min. Figure 2. Uterine recordings from patient K. B. showing the uterine response to locally administered PGF on the fourth (top) and ninth (bottom) days after%vutation.
from all 5 patients studied are summarized in figure 3. The intrauterine injection of saline at various phases of the menstrual cycle in amounts corresponding to the volumes of prostaglandin administered did not cause any uterine response. f
%3. 5 7_ Y6 w 5.
A
E z
0
.
t .
21.
.
A
8 b0 -I 3. 0 5
A
. .
. -12 -1’2 -lb
.
.
. -8
-b
-Z
DAYS BE!=ORE AND AFTER
. .
-2
‘0
.
.
.
i2 +L 45 th +io tl2 tfb
DAY OF OVULATION
( DAY 0)
Figure 3. Summary of threshold values for ~;L;e$$u~;;~&~;(q~
;;t;,“,ttz;;t;of
ovutation. The symbol (4) denotes the highest dose of prostaglandin which was administered without effect .
FEBRUARY
1975
VOL.
9 NO. 2
249
PROSTAGLANDINS
DISCUSSION The flaccid microballon technique for the recording of uterine contractility as described by several investigators has been shown to be as efficacious as the open-end method (9,10). The absence of problems involving obstructive uterine secretions which might require continuous flow systems with the open-end catheter and its inert suitability in connection with the study of effects following the concomitant administration of liquid agents such as constitute important merits of the flaccid microballoon technique PGF in th@study. Variations of inherent uterine contractility throughout the menstrual cycles of the six patients was comparable to the characteristic patterns described previously by others (10-X). In the proliferative phase the basic pattern was characterized by frequent moderate contractions of short duration, while around the time of ovulation contractional intensity was somewhat diminished and more regular. Into the secretory phase less frequent, larger and more irregular “pre-labor” contractions became increasingly predominant. Finally, during early menstruation, the contractions were generally regular, “labor-like” and measured up to 225-250 mm Hg in intensity. Notwithstanding that all recordings exhibited features of these general patterns, there was wide variation noted between patients. The present study demonstrates that the nonpregnant human uterus responds differentially to locally administered PGF2,, according to the time of ovulation and phase of the menstrual cycle. A relative insensitivity to natural PGF was noted in all patients both in the immediate pre- and post-ovulato?y period. As much as 7.5-8.0 ).+Iof the compound failed to stimulate the uterus at this time, in contrast to the stimulation observed with as little as 1.0-2.0 &g during other parts of the menstrual cycle. A significant increase in sensitivity during the immediate premenstrual period was not observed. The impossibility of objectively evaluating the into variable amounts of menstrual fluid during early injection of PGF 2oiuded investigations of this portion of the menstrual menstruation prec cycle. The intrauterine administration of saline to control patient I. P. , in volumes equivalent to the prostaglandin-containing solutions given to the other patients in these studies, failed to elicit any difference in uterine contractility at any time during the menstrual cycle. on the nonpregnant human Previous in vivo studies of the effect of PGF uterus have utilized single intravenous injec E” ions or infusions of the compound (l-4). Invariably an increase in uterine contractility was caused by single i. v. doses exceeding a threshold level of approximately 50 & (l-2). Such systemic studies cannot be applied to an understanding of either local uterine physiological events or variable uterine sensitivity since the amount of compound eventually reaching the uterus must be small and variable. Approximately 90% of an intravenously injected amount of prostaglandin will be inactivated during a single passage through the lungs (7). It has also
FEBRUARY
1975
VOL.
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in patients receiving an intrabeen shown that blood levels of PGF venous infusion of 75 pg/min for 10 i?ours ranged from 1.2 to 5.7 ng/ml (8). administration is by Embrey as The only report of intrauterine PGF quoted by Pickles aal. (5). Embre$ound that as little as 0.5 /*g PGF stimulated increased uterine contractility in two patients on days 24 ando 26 cf their menstrual cycles. Such a finding is compatible with the present results. The recording by Embrey was made, however, following a dilatation and curettage procedure which might have influenced the results. No further intrauterine studies investigating PGF sensitivity during the remainder of the menstrual cycle to our know i!age have appeared in the literature. Green and Hagenfeldt recently used the gas chromatography-mass spectrometry method to measure PGF and 15-keto-13,14-dihydro-PGF levels in the human endometriu%! during the menstrual cycle (16). %eir careful investigation showed that 15-keto-13,14-dihydro-PGF 2p’. the was present in the endome rmm in major serum metabolite of PGF high concentrations (55-1940 ngy$‘on day 22. At the time of ovulation, however, tissue levels of the compound were significantly lower and in most cases undetectable. The endometrial content of prostaglandin F20 followed a similar pattern -- higher concentrations of the parent compound being measured during the secretory phase (130-8280 rig/g)) than at the time of ovulation (65-5790 ng/g). At least during the late secretory phase such endogenous levels correspond to the exogenous amounts of PGF2e which elicited uterine reactivity when administered to the patients in the present study. These findings are compatible with the earlier work of Pickles et al. who found that (a) the primary prostaglandins are present in the human endometrium during both the proliferative and the secretory phase of the menstrual cycle; (b) endometrial tissue from the secretory phase has a higher content of PGF2o with an increased PGF:PGE ratio; and (c) menstrual fluid contains about 10 times more PGF 2a, than is found in secretory endometrial curettings (6). The present results and the above findings support the hypotheses that PGF plays an important physiological role in the cyclical regulation of uter&% motility during the menstrual cycle and that an overproduction of this compound during menstruation may be an important factor responsible not only for the increased myometrial activity seen but also for the pain of primary dysmenorrhea. Studies under way by Lundstrom et al. have shown that the treatment of some dysmenorrheic patients with prostaglandin biosynthetic inhibitor indomethacin has resulted in impressive symptomatic improvement and a reduction in recorded uterine tonus level (17). Midcycle, periovulatory insensitivity to locally administered PGF20 corresponds to the highest level of estrogen achieved during the menstrual FEBRUARY
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cycle. Such an interrelationship suggests that the myometrial reactivity to PGF may be under hormonal control similar to what has been report Zfr for vasopressin (18). A periovulatory decrease of inherent uterine motility may play a physioLogical role in sperm migration and fertilization. Since semen contains predominantly primary prostaglandin of the E-type as well as some F, investigation of PGE and its effect upon the nonpregnant human uterus during the menstrua?cycle will be of interest in helping to elucidate the role of prostaglandins in reproductive physiology. Such work is under way in our laboratory.
REFERENCES 1.
Roth-Brandel, U. , M. Bygdeman and N. Wiqvist. Effect of intravenous administration of prostaglandin E1 and F2o on the contractility of the nonpregnant human uterus in vlvo. Acta Obstet. Gynec. Stand. 49, Suppl. 5:19-25, 1970.
2.
Wiqvist, N. , U. Roth-Brandel and M. Bygdeman. The side effect on the nonpregnant human uterus -in of prostaglandin E and F Int. J. Gynei. & Ol%et. 8:165, 1970. m.
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Karim, S. M. M. , K. Hillier, K. Somers and R. R. Trusell. The effects of prostaglandins E2 and F20 administered by different routes on uterine activity and the cardiovascular system in pregnant and nonpregnant women. J. Obstet. Gynaec. Brit. Commonw. 78: 172-179, 1971.
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Coutinho, E. M. and H. S. Maia. The contractile response of the human uterus, fallopian tubes & ovary to prostaglandins in vivo. Fertil. Steril. 22:539-543, 1971.
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Pickles, V. R. , W. J. Hall, P. C. Clegg and T. J. Sullivan. Some experiments on the mechanism of action of prostaglandin of the guinea pig and rat myometrium. In: Endogenous Substances Affecting the Myometrium (eds. V. R. Pickles and R. J. Fitzpatrick), Mem. Sot. Endocrinol. 14:80-103, 1966.
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Pickles, V. R. , W. J. Hall, F. A. Best and G. N. Smith. Prostaglandins in endometrium and menstrual fluid from normal and dysmenorrheic subjects. J. Obstet. Gynaec. Brit. Commonw. 72: 185-192, 1965.
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Samuelsson, B. , E. Granstrijm, K. Green and M. Hamberg. Metabolism of prostaglandins. Ann. N. Y. Acad. Sci. 180:138, 1971. FEBRUARY
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8.
Green, K., F. Beguin, M. Bygdeman, M. Toppozada and N. Wiqvist. Analysis of prostaglandin F and metabolites following intravenous, intraamniotic and v$?$nal administration of prostaglandin F20. In: Prostaglandins in Fertility Control. WHO Conference. Stockholm (eds. S. Bergstrom, K. Green and B. Samuelsson): 189-200, 1972.
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Csapo, A. I. and C. R. Pinto-Dantas. The cyclic activity of the nonpregnant human uterus. Fertil. Steril. 17:34-38, 1966.
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Coutinho, E. Proceedings International International
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Hendricks, C. H. Activity patterns in the nonpregnant human uterus. In: Muscle (eds. E. Daniel, W. Paul, E. M. Kay. and G. Monckton). Pergamon Press, New York: 349-362, 1965.
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Hendricks, C. H. Inherent motility patterns and response characteristics in the nonpregnant human uterus. Am. J. Obstet. Gynec. 96:824-843, 1966.
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Moawad, A. H. and L. P. Bengtsson. In vivo studies of the motility patterns of the nonpregnant human uterus. Am. J. Obstet. Gynec. 98:1057-1064, 1967.
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Cibils, L. A. Contractility of the nonpregnant human uterus. Obstet. Gynec. 30:441-461, 1967.
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Hein, P.R. , T. K. A. B. Eskes, L.A. M. Stolte, J. T. Braaksma, J. Janssens and J. M. v.d. Hoek. The influence of steroids on uterine motility in the nonpregnant human uterus. In: Uterine Contraction (ed. J. B. Josimovick), John Wiley & Sons, Inc. : 107-128, 1973.
16.
Green, K. and K. Hagenfeldt. Prostaglandins in the human endometrium: Gas chromatographic-mass spectrometric quantitation before and after IUD insertion. Am. J. Obstet. Gynec. In press 1974.
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Lundstrijm,
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Coutinho, E. M. and A. C. V. Lopes. Response of the nonpregnant human uterus to vasopressin as an index of ovarian function. Am. J. Obstet. Gynec. 102:479-489, 1968.
FEBRUARY
M. Uterine activity in nonpregnant women. In: of the Eighth International Conference of the Parenthood Federation (eds. Hankinson et al.), Parenthood Federation, London: 432-49, 1967.
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