Progesterone and Estrogen Requirements to Induce and Maintain Decidua

Progesterone and Estrogen Requirements to Induce and Maintain Decidua James T. Bradbury, Sc.D., Robert C. Long, M.D., and W. C. Durham, M.D.

IN

PREVIOus STUDY 1 it was shown that when progesterone and estrogen were administered as aqueous suspensions, it was possible to induce and maintain decidual changes in human endometrium. During that study it was found that certain patients developed such painful areas of inflammation . and induration at the injection sites that treatment had to be discontinued. Similar observations from physicians who had used this aqueous suspension in their practice led to the preparation of an oil solution ( Cyclogesterin 2.5x). When this oil solution was used under our study conditions it was found to be ineffective for maintaining decidual changes in the endometrium. The present study consists: first, of a series of trials with different estrogens to determine their minimal and optimal doses when given with a standard 25 mg. daily dose of progesterone, and second, of different doses of progesterone in oil to determine whether larger doses would produce results similar to those obtained with aqueous suspensions of progesterone. A

PLAN OF STUDY

In the first part of this study, estrogens were administered orally and progesterone was given intramuscularly as an aqueous suspension or as an oil From the Department of Obstetrics and Gynecology, and Institute for Medical Research, University of Louisville, Louisville, Kentucky. This study was supported in part by a grant from the National Research Council Committee for Research in Problems of Sex, to Drs. Laman A. Gray and James T. Bradbury, and in part by a grant-in-aid from The Upjohn Company. Presented at the Eighth Annual Meeting of the American Society for the Study of Sterility, Chicago, Illinois, June 7, 1952. 63

64

BRADBURY ET AL.

[Fertility & Sterility

solution. Several oral estrogens were used;* natural conjugated estrogens ( Amnestrogen), diethylstilbestrol, equilin and sodium estrone sulfate. Another estrogen, estradiol cyclopetylpropionate, was given intramuscularly in oil. Crystalline progesterone was dissolved in this oil solution in concentrations of 50, 35, and 25 mg. per cc. The 50 mg. concentration was super~ saturated at room temperature so it had to be kept warm or heated before it was injected. Most of the study patients had a normal menstrual rhythm and many of them had also been observed in the previous study so it has been possible to compare the response of the same patient to various estrogens and to different doses of progesterone. Endometrial biopsies were obtained each week, except during menstrual periods, and treatment was usually started after the endometrium revealed secretory changes. EXPERIMENTAL RESULTS

Cyclogesterin 2.5x Six women were given daily injections of 1 cc. of Cyclogesterin 2.5x (progesterone 25 mg. and mixed estrogens 2.5 mg. per cc. of oil) starting in the postovulatory phase of a cycle. In no instance was there any signilicant delay in the onset of the expected menstrual period nor were there any decidual changes induced in the endometrium ( Fig. 1 ) . This uniform failure with an oil solution is in marked contrast to our earlier results with this same dose of estrogen and progesterone in an aqueous suspension. The difference in results seemed quite probably due to a difference in rate of absorption of these hormones from an oil solution and the rate at which the crystalline hormones were dissolved into the tissue fluids. It was decided to determine effective doses of oral estrogens so that the relative effectiveness of progesterone as crystals or in oil solution could be more easily evaluated. A. Progesterone as an Aqueous Suspension of Crystals In the following experiments four different oral estrogens were given in varying doses but the progesterone was given uniformly as intramuscular

* The hormone preparations used in this study-Cyclogesterin both aqueous and oily, equilin, sodium estrone sulfate, and microcrystalline progesterone which was dissolved into the oil solution of estradiol cyclopentylpropionate (which they also furnished) -were supplied by The Upiohn Company. The conjugated estrogens (Amnestrogen) were furnished by E. R. Squibb & Sons.

Vol. 4, No. 1, 1953]

INDUCTION OF DECIDUA

65

injections of the aqueous suspension of crystals and the dose was 25 mg. daily. 1. Stilbestrol This estrogen was given orally to three women in daily doses of 5 mg. The endometrium in each instance was converted into decidua and the expected menstrual periods were delayed at least three weeks when treatment was discontinued (see G.M. and G.W., Fig. 2). Three other subjects were given 1.0 mg. of stilbestrol daily and their menses had been de-

E. A.

p

s

p

0

B. G.

I

p

s

s 0

E.R.

I

I

s

I

0

B. G.

I

s

p

0

L.W.

p

~

s

p

PROGESTERONE

s '

2!5 MG.+ ESTROGEN

(CYCLOGESTRIN

2.!5 MG.

IN .OIL

2.!5 X)

Fig. 1. Failure of the oil solution of estrogen and progesterone (Cyclogesterin 2.5x) to delay the onset of an expected menstrual period or to induce development of decidua. Key to Figs. 1-5. The larger letters at the left are the patient's initials and the solid black blocks indicate the intervals of menstrual bleeding before and after the course of treatment. The smaller letters denote endometrial biopsies and the regular spacing at weekly intervals serves as a time scale. P indicates proliferative endometrium, S a secretory endometrium, and the small o under the S indicates an early secretory endometrium in which subnuclear vacuoles were present. D represents a decidual reaction, Mx a mixed type, and I, that the tissue was insufficient for classification. The first secretory biopsy in each cycle is arbitrarily plotted next to the solid vertical line. The two vertical broken lines (10 and 14 days after the solid vertical line) embrace the interval in which menstruation would normally be expected. The dosage and duration of treatment is indicated in the rectangles and the notations on each chart.

[Fertility & Sterility

BRADBURY ET AL.

66

layed at least one week when medication was terminated (see W.B. and A.L., Fig. 2). When the dose of stilbestrol was reduced to 0.5 mg. daily the results were equivocal since 3 out of 5 women so treated exhibited decidual changes and delay in onset of menses whereas the other 2 did not (Fig. 2).

-

G.M

G. w.

p

p

p

p

If s

s :

D

ll

I mLBESTROL s

.

: Q

I STI LIESTROL

w. e._ A.

'---

B. L.

-

A. L.

J.M

HOME

&.0 ... ,

D 5.0 MG.

I

: p

p

p

p

p

p

s

I

STILBESTROL

s

I ! p

p

p

Q

s

s :

Q

I STILBESTROL p

II

: -p

p

~

0.1 MG.

~

s

I STILBESTROL p

~

o_

I D

I

STILBESTROL · 1.0 MI.

s

f

1.0 MG.

0.5 MG.

:

s :......;.

-

o_

I D

I

PROIESTERONE IS MG. I.M. (AQUEOUS SUSPENSION I WITH EACH OAILY DOSE OF STILl EITROL I DRAL I

lo.no.l

L.W

-

•

p

s

s..;.

lo.&Ms.l'

Fig. 2. Results obtained when different doses of orally administered stilbestrol were given together with intramuscular injections of 25 mg. of progesterone in aqueous suspension. Stilbestrol in daily doses of 0.5 mg. were occasionally sufficient whereas 1.0 mg. was consistently sufficient to augment the action of the progesterone in the production of decidual changes.

On the basis of these findings it would seem that 0.5 mg. of stilbestrol is about the minimal effective dose and that 1.0 mg. daily would be consistently adequate to augment the action of 25 mg. of progesterone given daily as an aqueous suspension. 2. Con;ugated Estrogens Amnestrogen was first tried in 5.0 mg. daily doses in three women and was found effective since decidual changes were maintained for four weeks ( L.D. and W.B., Fig. 3.). When the dose of conjugated estrogens was reduced to 2.5 mg. daily, in only 2 of the 5 trials was

Vol. 4, No. 1, 1953]

INDUCTION OF DECIDUA

67

there any significant delay in the expected menses. A decidual cast was found in the vagina at the onset of bleeding in B.C. (Fig. 3) so the desquamation was complete while she was still on treatment. Doses of 1.25 mg. daily were too small to have any demonstrable effect in three instances. L.D

W.B

--

-

B.G

.....

B.W

H

-

H

5.0 MG.

p

p

.

s

s

11.0 MG.

-

p

p

p

s

-

L.W

w. 8.

-

sl

'

'

I

I

s

' I

I

I

i

D-

J

.

D

I

1

I

p

s

$

'

I

I

I

I

p

~

I

I

s

I I

I

Ill

s

I

I

I

I

I I

I

s

I.M.

OF

ESTROGEN.

-

-

~ l'-2~ MG. ~ST I

s

I

p

25 MG

WITH EACH DAILY DOSE

I

I

1.25 MG. ESTROGEN

p

PROGESTERONE

• ..._I

I

-

D

'?.12.5 MG. E~TROGE! I

I

p

D

I

ORAL ESTROGEN I I I I I D .,I I ORAL ESTROGEN

2.5 MG. ESTROGEN

W.B

I I

s

I I

I 0.5· MG.

I I I "I

EQUILIN

D

D

I

-

Fig. 3. Results obtained with different doses of conjugated estrogenic substances (Amnestrogen) given simultaneously with intramuscular progesterone (aqueous) 25 mg. daily. Doses of 5.0 mg. daily were consistently adequate whereas lower doses seem inadequate to augment the action of progesterone in the induction of the decidual reaction. A test with 0.5 mg. of equilin (one of the components of the mixture of conjugated estrogens) is appended for contrast. The responses of patient, W.B., in three different tests are included in this chart. L.D. had experienced several anovulatory cycles previously and her endometrium exhibited some hyperplasia at the time this treatment was started. It required two weeks of the combined treatment to develop the histologic pattern of normal premenstrual endometrium and subsequently the decidual changes evident in three successive biopsies.

These observations indicate that a daily dose of 2.5 to 5.0 mg. of the conjugated estrogens is necessary to augment the action of 25 mg. of progesterone. 3. Equilin Since the mixture of conjugated estrogens consists of sodium estrone sulfate and sodium equilin sulfate as well as other steroid conjugates,

68

[Fertility & Stedlity

BRADBURY ET AL.

it was of interest to try some of the individual components. Equilin was available in an unconjugated form for oral use and when given in 0.5 mg. daily doses there were three instances in eight trials where decidua was maintained for at least three weeks (see W.B., at bottom of Fig. 3). This indicates that 0.5 mg. of equilin is about as effective as 2.5 mg. of the mixture of conjugated estrogens. B.L.

I

J.M.

E.R.

p

-

p

p

p

p

p

p

~

s

s

I

s ~ I EQUILIN I

: ci I E.QUILI~ : ~ 1.~

s EQUILIN

R

D 2.0 MG.

+

I2SMG.

D

D 2.0 MG.

+

I25MG.

Mx MG.

+ lao MG.

: B. L.

E. A.

B. G.

J:M.

p

~-

~

-

s

-

-

p

s

I p

p

p

p

~

s

~

s :

s

D _Mx

EQUILIN

.

1.0 MG.

+

30 MG.

I I

:....:..

IEQU. ;,0 } ~0 MG. s : .....:.-

I 1gu.

1.0

I~

IOMG.

PROGESTERONE IN OIL OR 25 MG./CC. 30 MG. IN ICC. OF OIL

p.

p

p

.s

s :

IEQUILIN

......;.

;.o I +'ao Mt.

Fig. 4. Results obtained when equilin was administered as the oral estrogen and progesterone was administered intramuscularly in oil solution. The decidual reaction regressed after the same time interval at both doses of equilin in B.L. and regressed after 2 weeks in J.M. while on the 2 mg. dose of equilin. Since there was no instance of decidual maintenance beyond 2 weeks it seems evident that this dose of progesterone in oil is not adequate.

4. Sodium Estrone Sulfate Three women were given 5.0 mg. daily doses of pure sodium estrone sulfate but none of them experienced any significant delay in onset of bleeding or any decidual changes. We have not had the opportunity to try larger doses of sodium estrone sulfate but it seems evident that it is not the most effective estrogenic substance in the mixture of conjugated estrogens since 5.0 mg. of the pure substance was less potent than 5.0 mg. of the mixture.

Vol. 4, No. 1, 1953]

INDUCTION OF DECIDUA

69

B. Progesterone in Oil Solutions 1. Equilin Having found that orally administered equilin was effective in augmenting the action of progesterone in aqueous suspension it was decided to try it with oil solutions of progesterone. In this series of observations progesterone was given in 3 cc. of oil ( 10 mg. per cc.) or in 1 cc. of oil ( 25 mg. per cc. ) . Only 4 out of 7 women given 1 or 2 mg. of equilin daily exhibited consecutive decidual biopsies when the dose of progesterone was 25 or 30 S.F.. -

p

p

~

~

I

I

D

I ..iaoaEB!EAONE H. H...._

8..\..,..p

p

p

p

p

s

~

i, I P~OIISTEAONE : :

s

t

~

.I

D

J. L.

'-

p

p

s

D

A.L.

p

Q

D

q '

Q

s ,·

p

p

p

s PROlE ST.

E. A.

-

p

p

s

I+

..

M

-

ECP 1.0 MG.

-

ECP I.OM G.

~.l..... 25 MG.

s

+

935M&.

I+ ECP

1.0 MG.

_Mx

25 MG.

I P~OIES~. I

.!i

D

-

IC, 1.0

:

s

s s I PROGESTE~ONE ~

I+

35 MG

I P~OGES!ERONE p

D 50 MG.

I P~OGES~ERONE B. G.

I+

50 MG.

I+

!l~

+ ECP

·: E~P

ECP 1.0 MG.

0.5 MG.

1.0118.

PAOIEITERON E IN OIL WITH EC~ (ESTRADIOL CYC LDPENTYLPRO PIONATE)

:---

c!o ~

ECP 0.5 MG,

Fig. 5. Results obtained when estradiol cyclopentylpropionate was given intramuscularly together with progesterone in the same oil solution. Doses of 35 to 50 mg. of progesterone daily are necessary for maintaining decidua when it is given in an oil solution.

mg. daily (Fig. 4). The difference in dose of equilin ( 1 or 2 mg. ) was apparently not significant since B.L. responded equally well at either dose. The only impression that can be obtained from these observations is that 25 to 30 mg. of progesterone in oil is not as consistently effective in maintaining decidua as a similar dose of progesterone as a crystalline suspension, even though the same estrogen was given orally.

70

BRADBURY ET AL.

[Fertility & Sterility

2. Estradiol-cyclopentylpropionate The lower potency of progesterone in oil solution is further substantiated in the following experiment in which progesterone and the estrogen were combined in the same oil solution for intramuscular injection. Daily doses of 50 mg. or of 35 mg. of progesterone were adequate to induce and maintain decidua whereas doses of 25 mg. were usually inadequate (Fig. 5). These results indicate that doses of 35 to 50 mg. of progesterone in oil are necessary to match the effectiveness of 25 mg. of progesterone as microcrystals.

SUMMARY This experimental study is concerned with the determination of the amounts of progesterone and estrogen which are required to induce and maintain decidua. Women with normal menstrual records were used as study subjects and the hormonal treatment was started during the postovulatory (luteal) phase of their cycles and was continued until they started to bleed, or until their expected menstrual period had been delayed at least two weeks and decidual changes had been evident in at least two successive endometrial biopsies. Three sets of observations were completed. Six women were given daily intramuscular injections of 1 cc. of oil containing 25 mg. of progesterone and 2.5 mg. of progesterone and 2.5 mg. of mixed estrogens. This type of medication produced no significant alteration in the menstrual rhythm or endometrial histology. In our previous study this same dose of progesterone and estrogen, given as a suspension of crystalline hormones, had been uniformly effective in delaying the expected menstrual period for several weeks and maintaining decidual changes during that interval of time. In the second part of the study, four different oral estrogens were given in varying doses but the progesterone dosage was constant throughout; namely, 25 mg. daily as the aqueous suspension of crystals given intramuscularly. The results of this study show that the minimal effective dose of stilbestrol or equilin is 0.5 to 1.0 mg. daily for augmenting the action of 25 mg. of progesterone. The daily dose of conjugated estrogens was found to be 2.5 to 5.0 mg. whereas the fourth estrogen, sodium estrone sulfate, was not effective in doses of 5.0 mg. daily. Since equilin is four to five times as potent as sodium estrone sulfate and the mixtures of conjugated estrogens are labeled as standardized in terms .of their major component (sodium estrone sulfate), further study is warranted

l

i ~

~.

Vol. 4, No. 1, J 953]

INDUCTION OF DECIDUA

71

to determine what components of the mixture have made it so effective in clinical usage. In the third part of the study an oral estrogen, equilin, and an injectable estrogen, estradiol-cyclopentylpropionate, were administered together with varying doses of progesterone in oil. The results of these observations indicate that in an oil solution doses of 35 to 50 mg. of progesterone are necessary to match the effects of 25 mg. of progesterone as microcrystals. This difference in effectiveness is probably due to the rates at which it is taken into the circulation. It may be so rapidly absorbed from the oil that effective blood levels are not maintained by single daily injections of 25 mg. whereas the crystals dissolve slowly and give more stable blood levels. The recent work of Zander ( 1952) confirms this probability, in that after a single 150 mg. dose of progesterone crystals the maximum pregnanediol excretion was not attained until the third day. Furthermore when 500 mg. of progesterone was administered every fifth day in an oil solution, there was a maximum excretion on the first day and then a rapid decline and disappearance in the next 2 or 3 days after each injection. When the 500 mg. of progesterone was injected as an aqueous suspension every fifth day, the pregnanediol excretion was not only maintained but continued to increase until after the fourth injection. CONCLUSIONS 1. Further observations have been made on the daily dosages of the two hormones progesterone and estrogen which are necessary for the induction and maintenance of decidual endometrium. 2. Larger intramuscular doses of progesterone are required when it is administered in oil solution ( 35 to 50 mg. daily) than when it is given as microcrystals ( 25 mg. ) suspended in an aqueous media. 3. For augmenting the action of progesterone, stilbestrol and equilin were found to be about five times as potent as the conjugated estrogens and over ten times as potent as pure sodium estrone sulfate. REFERENCES LoNG, R. C., and BRADBURY, J. T. Induction and maintenance of decidual changes with progesterone and estrogen. ]. Clin. Erulocrinol. 11:134-145, 1951. 2. ZANDER, J. t!ber die Ausscheidung der c21-Glucuronide (Pregnandiolkomplex) nach Kontinuierlicher zufuhr Roher Progesterondosen. Klin. Wchnschr. 30:312315, 1952.

1.

72

BRADBURY ET AL.

[Fertility & Sterility

DISCUSSION DR. HENRYS. GUTERMAN, Chicago, Ill.: In the short time we have for discussion, I shall touch on several points. First, I should like to disagree with Dr. Bradbury. I do not believe that his presentation today is of only academic interest. This group is practical. It will apply and use the compounds which have been discussed today. The results that can be obtained are its primary interest. Therefore, it is of utmost importance to understand the characteristics of the products which were discussed. Dr. Bradbury has emphasized the significance of the selection of the proper hormone preparation for a particular purpose. On this point I agree with Dr. Bradbury. The rate of absorption of the hormone was one of the factors mentioned which may. modify the ability of progesterone to maintain decidual change. I should like to say that we (and others) have evidence that the absorption rates of progesterone given by different routes and in different preparations vary greatly. Last year Dr. Sommerville, who w~s working in Dr. Leo Samuels' laboratory, indicated that the intravenous administration of progesterone led to its disappearance from human blood in a very short time. Almost simultaneously, pregnandiol appeared in the circulating blood. Studies of our own have indicated that progesterone swallowed in pill form is excreted as pregnandiol within a matter of 24 to 48 hours. Progesterone in oil, administered by intramuscular injection, results in a slower rate of absorption, and the excretion of pregnandiol is complete at the end of approximately 72 hours. Aqueous suspensions may vary in their rates of absorption. Using a suspension similar to that described by Dr. Bradbury, we found that the excretion of pregnandiol began approximately 24 to 72 hours after administration and that the excretion was complete after 96 to 120 hours. However, with a different type of aqueous suspension the excretion of pregnandiol does not begin until3 to 4 days after administration of the hormone. We can see from this type of study that the rate of absorption is very variable and may modify the end result. Another factor which has to be considered is the concomitant administration of various estrogens with progesterone. Courrier's review in Vitamins and Hormones indicates that the action of estrogen and progesterone in combination depends to a large degree on the ratios of the two compounds. The relative amounts of estrogen and progesterone, within limits, determine whether a particular physiologic action of each hormone will be manifest. Further, the ratios vary for each action studied. The problem of administration of these hormones to produce the desired effect does not depend entirely on the hormones themselves. The recent studies of Hisaw and his collaborators indicate a complex process. Dr. Hisaw has shown that in rodents metabolic derivatives of progesterone, such as pregnandiol, may inhibit the development of deciduomata usually induced by progesterone. Therefore, the administration of hormones may lead to metabolic derivatives which, in turn, may inhibit the desired hormonal action. Our own studies indicate marked metabolic variations in the conversion of progesterone to pregnandiol in various phases of the menstrual cycle and in pregnancy. Furthermore, these metabolic

Vol. 4, No. 1, 1953]

INDUCTION OF DECIDUA

73

variations may have an intimate bearing on the functional activity of progesterone itself. In conclusion, I would like to state that the detailed studies discussed by Dr. Bradbury have practical significance but indicate that we are far from understanding completely the action of hormones which we must employ in the alleviation of various endocrine disturbances. DR. CHARLES L. BuXToN, New York City: I shall ask Dr. Guterman a question. When you say oral progesterone, do you mean anhydro-hydroxyprogesterone? DR. GUTERMAN: In answer to Dr. Buxton's question, when we speak of oral progesterone we refer to crystals of the hormone compressed in tablet form. DR. RICHARD FRANK, Chicago, Ill.: I congratulate Dr. Bradbury on a very excellent paper. It takes unusual patient material to enable the physician to take repeated, weekly endometrial biopsies. His ability to carry that out makes his work so much more important. I would like to take up one point: The essayist dealt with women with normal ovulatory cycles. His results are clear, very important, and well-corroborated by excretion values of pregnandiol, as pointed out by Dr. Guterman. We have recently been interested in a group of amenorrheic patients who presented no other demonstrable pathology. The problem was not to produce a decidual change, but to produce a secretory endometrium. We have limited the time of the experiment. We did not try to run these patients on 10, 15, or 21 days of progesterone therapy because of the difficulty of having the patients report at frequent enough intervals. With doses comparable to those used by Dr. Bradbury, we were able to produce a progestational response in some patients, but failed in others. The response was commensurate with the amount of progesterone used. We were unable to demonstrate any decidual reaction in our series up to this point. These patients, and I think it is quite important to stress this point, differ from those whom Dr. Bradbury used in his investigations. That faot is also corroborated by the pregnandiol excretion values which we obtained in our patients. They showed the following: Progesterone conversion into pregnandiol in these patients was low, and the ratio corresponded to the conversion rate that we see in the preovulatory phase in normal ovulating women. There is, in our opinion, a difference in endometrial response to progesterone in the amenorrheic compared to the normal patient. DR. JoHN WEED, New Orleans, La.: I do not wish to discuss the paper, but I would like to add a little information on the long-continued use of progesterone. Some years ago we were interested in the effect of long-continued progesterone on fibroid tumors of the uterus. In the course of study, we used progesterone in oil as well as tablets of progesterone implanted in the subendothelial region. These tablets were kept in place for as long as 3 months and were weighed at the completion of the experiment. The interesting thing is that though estrogens were not given concomitantly, the effect of estrogens in these patients allowed the menses to continue, though the bleeding was reduced. A study of the endometrium during

74

BRADBURY ET AL.

[Fertility & Sterility

the period the tablets were in place showed a gradual decrease in the thickening of the endometrium, so that at the conclusion of the experiment at 3 months a very thin, atrophic endometrium was present. Biopsies of the endometrium throughout the course of the experiment continued to show some evidence of progesterone effect on the nuclear vacuole. At no time, however, was decidual reaction obtainable. Possibly these patients failed to secrete enough estrogen to cause a decidual reaction. DR. ERNEST PAGE, Berkeley, Calif.: From a practical therapeutic standpoint this presentation naturally calls to mind that small group of women who appear to ovulate but who have a deficiency of corpus luteum function. From the standpoint of stimulation, I presume that chorionic gonadotropin would be the most potent luteotropic substance. I have converted some seemingly hopeless sterility cases into chronic, habitual aborters by using this hormone. I would like to ask Dr. Bradbury if he would comment on the time he has been able to maintain decidua with progesterone as compared to chorionic gonadotropin. DR. JAMES T. BRADBURY, closing: I appreciate the discussion which this presentation has stimulated. To answer the first question: "Are the severe local reactions following the injection of crystalline progesterone due to the hormone or to the repository?" I do not know. There is some evidence that the size of the crystals in the suspension may be the important factor. Several years ago we tried one lot of very large crystals of progesterone that proved most unsatisfactory and painful. Not being a physician, I should refrain from comments on this situation, but these inflammatory areas do develop several days after the injection when the suspending medium has most probably been completely absorbed. Dr. Guterman's comment on the ratio of estrogen to progesterone is valid in experimental animals, where a little estrogen does override the progesterone. If you recall our lantern slide, the dosage of stilbestrol was varied from 5 mg. down to 0.5 mg., changing the ratios from 1:5 to 1:50. Furthermore, there are many instances in which stilbestrol has been given in doses of 100 mg. or more to pregnant women without evidence of the estrogen overriding the progesterone. This would make it seem probable that the level of estrogen is more important than the ratio of estrogen to progesterone. Dr. Rakoff's comments on vaginal smear studies of women treated with equilin are interesting. We have also made similar studies and found that, given orally, equilin is about twice as potent as estrone, and that estrone is about twice as effective as sodium estrone sulfate. There has been an erroneous clinical impression that estrone is not effective when given orally, unless it is in a conjugated form. Dr. Frank's comment about amenorrheic women being less responsive may be a very important factor. In our clinic we have seen a number of women who required very large doses of estrogen to induce bleeding. Undoubtedly there are some conditions in which the utilization and the metabolism of the hormones are very abnormal. Dr. Goldzieher reported several cases of psychogenic amenorrhea

Vol. 4, No. 1, 1953]

INDUCTION OF DECIDUA

75

which were totally resistant to estrogen therapy. It is possible that some tissues, such as a hyperplastic adrenal cortex, may convert an estrogen to a nonestrogen very quickly. The women included in this study were in a State Hospital for the Insane and, for the most part, were selected on the basis of having regular cycles, as revealed by weekly biopsies and menstrual history. Obviously, this group of patients differs from those which Dr. Frank has found less responsive to estrogen-progesterone therapy. The question concerning our preference for progesterone or chorionic gonadotropin is interesting. Several years ago Dr. Brown and I felt that there might be some cases in which the corpus luteum is hypoactive. In such cases ovulation might occur normally, but the lack of progesterone and estrogen would fail to prepare the endometrium sufficiently for implantation even though fertilization did occur. In such cases chorionic gonadotropin should stimulate the corpus luteum to full activity, and then the developing placenta would produce enough gonadotropin to maintain the corpus luteum during the early part of pregnancy. If progesterone were administered, rather than gonadotropin in such cases, the corpus luteum would probably involute and the combined estrogen and progesterone therapy would have to be continued for 3 or 4 months until their production by the placenta was adequate to maintain the pregnancy.