- Email: [email protected]
360. Studies on Leydig cell function in old rats
886
Abstracts
other hormones. The use of a single suppository terminated the pregnancy in 82.6”,, of the cases during the mean induction-abortion interval of 16.6 k 1.3 hr. The sum of free acid and methyl ester of IS-me-PGF,, showed an Initial increase up IO two hours followed by a sustained levels until twelve hours. Of the successful cases 81.5”,, had a complete abortion. The mean episode of diarrhoea and vomiting per patient was 1.72 and 1.55 respectively. Of the failed cases. 64.7”,, were nulliparous and 67.1 per cent experienced gasteroinlestinal side effects. indicating at least some systemic absorption of the drug. Our earlier studies on 896 women where abortion was induced by prostaglandins given by intra-amniotic. extra-amniotic. intramuscular and in the form of multiple dose suppositories revealed a success rate of 99. 77. 98 and 94”., respecttvely. The use of single suppository. being a simple and non-invasive drug delivery system. appears IO be a fairly acceptable method for the termination of mid-trimester pregnancy. Its mechanism of abortifacient action seems to involve initiation of uterine contractions along with the decline tn the levels of estradiol-17/?. progesterone and HPL.
357. Changes in plasma progesterone concenfrstions during regression of corpora lutea induced by prostaglnndin Fz, and cloprostenol in dairy cows BAISHYA*. N. and POPE. G. S.. National Institute for
14. AGEING 358. Plasma steroids: correlation with age in normal women DRAFTA. D.. SCHISDLER. A. E.* and STROE. E.. Institute of Endocrinology. 34 Bd. Aviatortlor 71279 Bucharest. Romania and lUniversiIiiIsfrauenklinik. Tubingen. Federal Republic of Germany Plasma cortisol. estrone. estradiol. progesterone and 17 hydroxyprogesterone were determined by radioimmunoassay after LH-20-Sephadex column separation in normal ambulatory pre- and postmenopausal women (40 and 39 cases respectively). The most important age-linked changes found in this study were: the decrease of cortisol. estrone. estradiol and progesterone with the decade groups. and the significant increase of E, E2 ratio and l7-hydroxy-progesterone in postmenopausal women as compared with the premenopausal mid-cycle mean-values. The E, E2 ratio was positively correlated with the age (P < 0.001) but dtd not correlate with the LH FSH ratio. In the latter part of the menstrual cycle a significant increase of I7-OH-P and progesterone was noted.
359. Serum steroid profiles from oeonatal to ageing male rats in correlation lo fertilit) SAKESA. S. K.. LAU. I. F.. CHALIVIN. C. M. and CHAN~I. M. C.. Worcester Foundatton for Experimental Biology. Shrewsbury. MA 01545. U.S.A. The concentration of steroids in the same blood serum of male rats from age 12 through IO 450 days were determined by radioimmunoassay. Testosterone (T) was low (270-400 pg;‘ml) until day 42: adult levels (3-4 ng mll were attained within the next 10 days. Testosterone levels declined IO I ng,ml at old age. 5x-Dihydrotesrosterone (DHT) was stable (9&16Opg;mll from prepubertal IO advanced age. Apart from a peak (687 4 67 pg:ml) on day 22 of age. androstenedione (A4At was 40&5OOpg ml between 32-70 days and declined towards old age. Progesterone rose steadily from 0.6 + 0.1 ng,ml on day I2 IO 5.46 f 0.3 ng:‘ml at 52 days of age and gradually declined
Research England
In Dauying.
Shintield.
*Present address: College of Vet). University. Gauhatt 7x1022. lndta
Reading Sctence.
RC2
9AT.
Assam
Agrt.
The change rn pertphcral plasma progesterone concentration of diestrous cows after the tnjectton of prostaglandin F,, or cloprostenol tsynrhettc analogue of PGF,,) marks the course of Induced luteolys~s. The pattern of progesterone concentrattons 1s strikingly stmtlar for PGF2, and cloprostenol trcatmenr. Most cows showed a rtse of progesterone concentrations m the I5 mm after the tnjection but thts was not statistically stgnificant. There was then a very raptd fall In progesterone concentrations between 15 and 45 mtn after the injectton. After this intttal fall. there was a tcndcncy for progesterone concentrattons to rtse unttl about 2 h: levels then remained approxtmately constant before falltng again sharply between 4 and 5 h after the Injection. After this ttme the levels fell more steadily. and continued to decltne unit1 they reached theu lowest concentrattons between 60 and 6X h after the treatment. The rcsuhs suggc%. primnrtiy that the first raped fall in mean progatcronc concentrattons IS due to a hpecitic blockmg of progesterone productton by Ihc luteal cells or of its release from the ovary and the rise following the sharp fall 13 due IO the tnllucnce of Increasing levels of pttun;lry LH measured III rhts time.
AND STEROIDS from 62 through IO 450 days of age. Hugh levels of estronc (267.6 _’ 37.6 pg ml) and estradiol-I 78 (2.76 + 0.2 ng ml1 in I2 day old males. as opposed IO the lower estrogen (2&35pg ml) levels III adult and aged animals were observed. The T DHT ratio before maturity was IOU. mcreased in adults and decreased towards old age. Similar temporal changes in T A”A and lotal androgen lotal eslrogen ratios were recorded. Ageing males who had lower levels of steroids exhibited normal sexual drive and were fertile but the pregnant females had a signtficantly reduced number of fetuses. (Supported by the Ford Foundation.)
360. Studies on Leydig cell function in old rats PIRKE. K. M.. VOC;T. H. J. and GEISS. M.. Max Planck Instnur Psychiatric. Ableiiung Klin. Chemie. Dermalologische Klinik der Technischen Unnersitiit. Munchen. Federal Republic of Germany Leydtg cell functton decreases In old age In many mammalian spectes including man. We have studted young I.3 month. ii = 24) and old (2628 month. n = 20) rats ijr rr~ro and in r’1r.o In order IO gain further informatton on the ngeing of the male gonads. Testtcular weight did not change with age and was 1.66~ (1.33-2.66) in the young and 1.62g (1.~-1.90) In the old rats. The capacity of the LH receptors was significantly reduced in old rats (P < 0.01). 3.69 (1.X8-3.77) ng iodtnated HCG were specifically bound by IOOmg testes of the young rats. In the old rats the binding capacity was I.91 (0.80-3.02) ng. Testosterone (T) was 302 f. 126 ng 100 ml In plasma of young and IO5 4 59 ng 100 ml in rats. LH was old 52.9 k 31.1 ng ml in young and 39.2 t 25.2 ng ml m old rats. 111 rirro incubation studies with isolated Leydig cells revealed no differences in the sensitivity of young and old cells for HCG stimulation. The maximal response however was greater in young (194 + 33fg T cell) than in old rats (I 57 + 35 fg T cell). In conclusion. not only decreased LH secretion but also a decrease in LH receptor capacity. and
Abstracts the diminished ability of the Leydig cells IO produce T under gonadotrophin stimulation. may contribute to the agedependent fall in gonadal hormone secretion
-361 Plasma progesterone. and 17+oestradiol
testosterone, dihydrotestosterone change with age in man
BARLI-TTA. D.. FRAs(.tn. F.. GALI.I. P.. PAUI(.III. M.. D~L Gi.uovcsi:. A. and Luisi. M.. Postgraduate School of Endocrinology and Endocrine Laboratory of C.N.R.. ISI Medical Clinic Pisa University School of Medlclnc. 56100 Plsa. Italy Plasma progesterone (PI. testosterone (T). dihydroteslostcrone (DHT) and 17-/j-ocstradiol (El). were measured in 196 normal. adult men aged between I9 7X years. All steroids have been determined. after cxtractlon and horizontal thinlayer chromatographlc separation. by using a sensitive and rcllable radlolmmunoassay. In three age groups between 19-39. 40-59 and 6&7X. the means k S.D. for plasma P were 0.048 f 0.006. 0.045 & 0.004 and 0.034 f 0.007 t11g lOOmI). respcctlvely. The correspondlnp levels for T wcrc 565 + 2X. 54X + 16 and 461 f 37 (ng lOOmI): while for DHT the mean \~IULJ were 6X f 7. 63 & 5 and 39 + 7 (ng IOOml). respcctibely. Finally. the means + S.D. for plasma E, were 46 f 5. 34 2 5 and 15 & 6 (pg.ml). respectlvely. There was a moderate decline In the P and T levels of the 60 7X years age group compared to 19 39 years. but there were no sigmficant changes for both steroids between other groups. A sigmficant decrease was observed in the DHT plasma lebels of the 6&78 years ape group compared to either the 19.-39 IP < 0.01) and the &%54 (P c 0.05) age groups. Also plasma Ez shows a slenificant decrease of the 40 59 (P c 0.01) and 60-7X . (P < 0.01) years age groups compared to 19 39 years age group. From these results it may be concluded that the decrease ulth age of plasma DHT and Ez represent an Important and early sign of testicular functional deficiency in aged man.
362. Endocrine aspects of ageing in male rats LCPO DI ~RISCO. C and DESSI’-FUL(;HERI. F.. Institute of Human Physiology. University or Siena and Institute of Zoology. Umbersity of Firenze. Italy Endocrine effects of age and ageing were studied in four groups of Sprague Dawley male rats (2. 6. 12. 24 months old). The animals. reared m the laboratory. were sacrificed by decapitation. Blood. brain. gonads and adrenals were collected. Plasma testosterone and cstradlol were determined b) radiolmmunoassay. plasma cortlcosterone by competltne-protein binding. after thin layer chromatography purification. Acetone powder from brain. gonads and adrenals was incubated with testosterone. dehydro-
15. STEROIDS
364. Sparing e6ect of pyridoxine adrenal cortex
on tbe functions
of tbe
KALYANKAR. G. S.. VENKATESH. T. and RAMANI. S. N.. St. Department of Biochemistry and Biophysics. John’s Medical College. Bangalore 34. India The corticosteroids are physiological and metabolic instance. in adrenalectomized (B uv- ,
known to regulate diverse functions in mammals. For rats. there is diuresis. amino
887
cpiandrostcronc and progotcronc, rcspcctlvcly. Pl;lsrn~~ testnstcrone dccrcrrsed with age and agclng. plasma cstr;ldiol decrcascd From 1 IO 6 months. then incrcascd from 6 IO I? months and dccreascd with agemg. Plasma corticosterone did not show significant modilications. Ebtrudlol biosynthnlzed in the braln from tcstostcronc incrcaxcd from 2 to 6 months. then it dccrcascd. Tcscostcronc bloynthesized in the gonad from dehydroeplandrostcronc Increased from 2 IO 6 months then It dccrcascd. Cortlcosterone and 17x-hydroxyprogateronc blosynthal7cd m the adrenal from progestcronc decreased with agcmg.
363. Observations
on l7-oxo-steroids. testosterone and S-alfa-androstaaediol pattern under basal conditions and after acute and prolonged stimulation in preageing and sgeing male subjects.
STROLLO. F.. RIONDINO. G.. PIXNI(.IARO. G. and Endocrinological and PATRONO.’ V.. I.N.R.C.A., Metabolic Diseases Research Institute. Via Cassia 1167. Roma. Italy: and “Endocrineia” Foundation. Via Fogliano 15. Roma. Italy In a group of 60 healthy males. blood concentrations or FSH. LH and testosterone were determined before and alter acute pituitary stimulation by GnRH. Urinary concentrations of gonadotrophins. testosterone. epitnloslerone. 5-alpha-androstanediol and l7-oxo-steroids were also determined in the same subjects before and after prolonged testicular stimulation by HCG. The patients selected lor this study were divided in two age groups. one consisting of 30 subjects 5&60 years old. the other of 30 subjects over 60 years old. The analysis and statistical evaluation of the results of this study suggest that senile modltications of the hypophyseal-testicula axis correspond to those generally recognised so far. We can summarise them as follows: (a) pituitary gonadotrophin secreting activity progressively increases with age and the hypophysis is still responsive IO an adequate hypothal stimulus in old people: (b) Leydig-cell testosterone secreting ability decreases with age: (c) the amount of testosterone undergoing peripheral metabolic transformation is reduced: (d) testicular HCGinduced secretory response decreases m the elderly: (e) urinary excretion rate of androgen metabolites I l7-oxo-steroids and epitestosteronel remains within physiological limits. even in subjects over sixty. in whom. however. it shows a poor response IO HCG: (tl the difference between urinary S-alpha-androstanediol and testosterone excretion rate in ageing subjects is only slightly less than that in younger ones: in the ageing group this parameter shows some decrease after prolonged HCG stimulation. due to a more marked increase in testosterone than in androstanediol urinary excretion rate. thus suggesting a decrease in testosterone metabolism in target tissues.
AND
NUTRITION
aciduria. increased excretion ol ammonia. and disturbance in electrolyte balance. The additional observations are that there are decreased activities of pyridoxal phosphate dependent enzymes. such as aminotransferaseb amino acid decarboxylases and also a reduction in the pyridoxal content of the tissues. When the adrenalectomized rats were fed a diet with added pyridoxine (2.5 mg/‘lOOg body weight). the above metabolic and excretory changes came to normal or near normal.
Abstracts
other hormones. The use of a single suppository terminated the pregnancy in 82.6”,, of the cases during the mean induction-abortion interval of 16.6 k 1.3 hr. The sum of free acid and methyl ester of IS-me-PGF,, showed an Initial increase up IO two hours followed by a sustained levels until twelve hours. Of the successful cases 81.5”,, had a complete abortion. The mean episode of diarrhoea and vomiting per patient was 1.72 and 1.55 respectively. Of the failed cases. 64.7”,, were nulliparous and 67.1 per cent experienced gasteroinlestinal side effects. indicating at least some systemic absorption of the drug. Our earlier studies on 896 women where abortion was induced by prostaglandins given by intra-amniotic. extra-amniotic. intramuscular and in the form of multiple dose suppositories revealed a success rate of 99. 77. 98 and 94”., respecttvely. The use of single suppository. being a simple and non-invasive drug delivery system. appears IO be a fairly acceptable method for the termination of mid-trimester pregnancy. Its mechanism of abortifacient action seems to involve initiation of uterine contractions along with the decline tn the levels of estradiol-17/?. progesterone and HPL.
357. Changes in plasma progesterone concenfrstions during regression of corpora lutea induced by prostaglnndin Fz, and cloprostenol in dairy cows BAISHYA*. N. and POPE. G. S.. National Institute for
14. AGEING 358. Plasma steroids: correlation with age in normal women DRAFTA. D.. SCHISDLER. A. E.* and STROE. E.. Institute of Endocrinology. 34 Bd. Aviatortlor 71279 Bucharest. Romania and lUniversiIiiIsfrauenklinik. Tubingen. Federal Republic of Germany Plasma cortisol. estrone. estradiol. progesterone and 17 hydroxyprogesterone were determined by radioimmunoassay after LH-20-Sephadex column separation in normal ambulatory pre- and postmenopausal women (40 and 39 cases respectively). The most important age-linked changes found in this study were: the decrease of cortisol. estrone. estradiol and progesterone with the decade groups. and the significant increase of E, E2 ratio and l7-hydroxy-progesterone in postmenopausal women as compared with the premenopausal mid-cycle mean-values. The E, E2 ratio was positively correlated with the age (P < 0.001) but dtd not correlate with the LH FSH ratio. In the latter part of the menstrual cycle a significant increase of I7-OH-P and progesterone was noted.
359. Serum steroid profiles from oeonatal to ageing male rats in correlation lo fertilit) SAKESA. S. K.. LAU. I. F.. CHALIVIN. C. M. and CHAN~I. M. C.. Worcester Foundatton for Experimental Biology. Shrewsbury. MA 01545. U.S.A. The concentration of steroids in the same blood serum of male rats from age 12 through IO 450 days were determined by radioimmunoassay. Testosterone (T) was low (270-400 pg;‘ml) until day 42: adult levels (3-4 ng mll were attained within the next 10 days. Testosterone levels declined IO I ng,ml at old age. 5x-Dihydrotesrosterone (DHT) was stable (9&16Opg;mll from prepubertal IO advanced age. Apart from a peak (687 4 67 pg:ml) on day 22 of age. androstenedione (A4At was 40&5OOpg ml between 32-70 days and declined towards old age. Progesterone rose steadily from 0.6 + 0.1 ng,ml on day I2 IO 5.46 f 0.3 ng:‘ml at 52 days of age and gradually declined
Research England
In Dauying.
Shintield.
*Present address: College of Vet). University. Gauhatt 7x1022. lndta
Reading Sctence.
RC2
9AT.
Assam
Agrt.
The change rn pertphcral plasma progesterone concentration of diestrous cows after the tnjectton of prostaglandin F,, or cloprostenol tsynrhettc analogue of PGF,,) marks the course of Induced luteolys~s. The pattern of progesterone concentrattons 1s strikingly stmtlar for PGF2, and cloprostenol trcatmenr. Most cows showed a rtse of progesterone concentrations m the I5 mm after the tnjection but thts was not statistically stgnificant. There was then a very raptd fall In progesterone concentrations between 15 and 45 mtn after the injectton. After this intttal fall. there was a tcndcncy for progesterone concentrattons to rtse unttl about 2 h: levels then remained approxtmately constant before falltng again sharply between 4 and 5 h after the Injection. After this ttme the levels fell more steadily. and continued to decltne unit1 they reached theu lowest concentrattons between 60 and 6X h after the treatment. The rcsuhs suggc%. primnrtiy that the first raped fall in mean progatcronc concentrattons IS due to a hpecitic blockmg of progesterone productton by Ihc luteal cells or of its release from the ovary and the rise following the sharp fall 13 due IO the tnllucnce of Increasing levels of pttun;lry LH measured III rhts time.
AND STEROIDS from 62 through IO 450 days of age. Hugh levels of estronc (267.6 _’ 37.6 pg ml) and estradiol-I 78 (2.76 + 0.2 ng ml1 in I2 day old males. as opposed IO the lower estrogen (2&35pg ml) levels III adult and aged animals were observed. The T DHT ratio before maturity was IOU. mcreased in adults and decreased towards old age. Similar temporal changes in T A”A and lotal androgen lotal eslrogen ratios were recorded. Ageing males who had lower levels of steroids exhibited normal sexual drive and were fertile but the pregnant females had a signtficantly reduced number of fetuses. (Supported by the Ford Foundation.)
360. Studies on Leydig cell function in old rats PIRKE. K. M.. VOC;T. H. J. and GEISS. M.. Max Planck Instnur Psychiatric. Ableiiung Klin. Chemie. Dermalologische Klinik der Technischen Unnersitiit. Munchen. Federal Republic of Germany Leydtg cell functton decreases In old age In many mammalian spectes including man. We have studted young I.3 month. ii = 24) and old (2628 month. n = 20) rats ijr rr~ro and in r’1r.o In order IO gain further informatton on the ngeing of the male gonads. Testtcular weight did not change with age and was 1.66~ (1.33-2.66) in the young and 1.62g (1.~-1.90) In the old rats. The capacity of the LH receptors was significantly reduced in old rats (P < 0.01). 3.69 (1.X8-3.77) ng iodtnated HCG were specifically bound by IOOmg testes of the young rats. In the old rats the binding capacity was I.91 (0.80-3.02) ng. Testosterone (T) was 302 f. 126 ng 100 ml In plasma of young and IO5 4 59 ng 100 ml in rats. LH was old 52.9 k 31.1 ng ml in young and 39.2 t 25.2 ng ml m old rats. 111 rirro incubation studies with isolated Leydig cells revealed no differences in the sensitivity of young and old cells for HCG stimulation. The maximal response however was greater in young (194 + 33fg T cell) than in old rats (I 57 + 35 fg T cell). In conclusion. not only decreased LH secretion but also a decrease in LH receptor capacity. and
Abstracts the diminished ability of the Leydig cells IO produce T under gonadotrophin stimulation. may contribute to the agedependent fall in gonadal hormone secretion
-361 Plasma progesterone. and 17+oestradiol
testosterone, dihydrotestosterone change with age in man
BARLI-TTA. D.. FRAs(.tn. F.. GALI.I. P.. PAUI(.III. M.. D~L Gi.uovcsi:. A. and Luisi. M.. Postgraduate School of Endocrinology and Endocrine Laboratory of C.N.R.. ISI Medical Clinic Pisa University School of Medlclnc. 56100 Plsa. Italy Plasma progesterone (PI. testosterone (T). dihydroteslostcrone (DHT) and 17-/j-ocstradiol (El). were measured in 196 normal. adult men aged between I9 7X years. All steroids have been determined. after cxtractlon and horizontal thinlayer chromatographlc separation. by using a sensitive and rcllable radlolmmunoassay. In three age groups between 19-39. 40-59 and 6&7X. the means k S.D. for plasma P were 0.048 f 0.006. 0.045 & 0.004 and 0.034 f 0.007 t11g lOOmI). respcctlvely. The correspondlnp levels for T wcrc 565 + 2X. 54X + 16 and 461 f 37 (ng lOOmI): while for DHT the mean \~IULJ were 6X f 7. 63 & 5 and 39 + 7 (ng IOOml). respcctibely. Finally. the means + S.D. for plasma E, were 46 f 5. 34 2 5 and 15 & 6 (pg.ml). respectlvely. There was a moderate decline In the P and T levels of the 60 7X years age group compared to 19 39 years. but there were no sigmficant changes for both steroids between other groups. A sigmficant decrease was observed in the DHT plasma lebels of the 6&78 years ape group compared to either the 19.-39 IP < 0.01) and the &%54 (P c 0.05) age groups. Also plasma Ez shows a slenificant decrease of the 40 59 (P c 0.01) and 60-7X . (P < 0.01) years age groups compared to 19 39 years age group. From these results it may be concluded that the decrease ulth age of plasma DHT and Ez represent an Important and early sign of testicular functional deficiency in aged man.
362. Endocrine aspects of ageing in male rats LCPO DI ~RISCO. C and DESSI’-FUL(;HERI. F.. Institute of Human Physiology. University or Siena and Institute of Zoology. Umbersity of Firenze. Italy Endocrine effects of age and ageing were studied in four groups of Sprague Dawley male rats (2. 6. 12. 24 months old). The animals. reared m the laboratory. were sacrificed by decapitation. Blood. brain. gonads and adrenals were collected. Plasma testosterone and cstradlol were determined b) radiolmmunoassay. plasma cortlcosterone by competltne-protein binding. after thin layer chromatography purification. Acetone powder from brain. gonads and adrenals was incubated with testosterone. dehydro-
15. STEROIDS
364. Sparing e6ect of pyridoxine adrenal cortex
on tbe functions
of tbe
KALYANKAR. G. S.. VENKATESH. T. and RAMANI. S. N.. St. Department of Biochemistry and Biophysics. John’s Medical College. Bangalore 34. India The corticosteroids are physiological and metabolic instance. in adrenalectomized (B uv- ,
known to regulate diverse functions in mammals. For rats. there is diuresis. amino
887
cpiandrostcronc and progotcronc, rcspcctlvcly. Pl;lsrn~~ testnstcrone dccrcrrsed with age and agclng. plasma cstr;ldiol decrcascd From 1 IO 6 months. then incrcascd from 6 IO I? months and dccreascd with agemg. Plasma corticosterone did not show significant modilications. Ebtrudlol biosynthnlzed in the braln from tcstostcronc incrcaxcd from 2 to 6 months. then it dccrcascd. Tcscostcronc bloynthesized in the gonad from dehydroeplandrostcronc Increased from 2 IO 6 months then It dccrcascd. Cortlcosterone and 17x-hydroxyprogateronc blosynthal7cd m the adrenal from progestcronc decreased with agcmg.
363. Observations
on l7-oxo-steroids. testosterone and S-alfa-androstaaediol pattern under basal conditions and after acute and prolonged stimulation in preageing and sgeing male subjects.
STROLLO. F.. RIONDINO. G.. PIXNI(.IARO. G. and Endocrinological and PATRONO.’ V.. I.N.R.C.A., Metabolic Diseases Research Institute. Via Cassia 1167. Roma. Italy: and “Endocrineia” Foundation. Via Fogliano 15. Roma. Italy In a group of 60 healthy males. blood concentrations or FSH. LH and testosterone were determined before and alter acute pituitary stimulation by GnRH. Urinary concentrations of gonadotrophins. testosterone. epitnloslerone. 5-alpha-androstanediol and l7-oxo-steroids were also determined in the same subjects before and after prolonged testicular stimulation by HCG. The patients selected lor this study were divided in two age groups. one consisting of 30 subjects 5&60 years old. the other of 30 subjects over 60 years old. The analysis and statistical evaluation of the results of this study suggest that senile modltications of the hypophyseal-testicula axis correspond to those generally recognised so far. We can summarise them as follows: (a) pituitary gonadotrophin secreting activity progressively increases with age and the hypophysis is still responsive IO an adequate hypothal stimulus in old people: (b) Leydig-cell testosterone secreting ability decreases with age: (c) the amount of testosterone undergoing peripheral metabolic transformation is reduced: (d) testicular HCGinduced secretory response decreases m the elderly: (e) urinary excretion rate of androgen metabolites I l7-oxo-steroids and epitestosteronel remains within physiological limits. even in subjects over sixty. in whom. however. it shows a poor response IO HCG: (tl the difference between urinary S-alpha-androstanediol and testosterone excretion rate in ageing subjects is only slightly less than that in younger ones: in the ageing group this parameter shows some decrease after prolonged HCG stimulation. due to a more marked increase in testosterone than in androstanediol urinary excretion rate. thus suggesting a decrease in testosterone metabolism in target tissues.
AND
NUTRITION
aciduria. increased excretion ol ammonia. and disturbance in electrolyte balance. The additional observations are that there are decreased activities of pyridoxal phosphate dependent enzymes. such as aminotransferaseb amino acid decarboxylases and also a reduction in the pyridoxal content of the tissues. When the adrenalectomized rats were fed a diet with added pyridoxine (2.5 mg/‘lOOg body weight). the above metabolic and excretory changes came to normal or near normal.