Comparative Effects of Estrogen, Testosterone, and Progesterone on Benign Mammary Tumors of the Rat* Jacob Heiman, M.D

(From the Department o[ Cancer Research, College o/ Physicians and Surgeons, Columbia University, New York, N. Y.) (Received for publication July Io, 1942 )

The effects of estrogens and androgens on the growth Autotransplants were put into 4 and homotrans- of benign fibroadenoma have already been reported plants into 6o Wistar animals, divided into the fol- (6, 8). The present record deals with the effects on lowing series: similar tumors of progesterone, and compares the (a) Four females with spontaneous tumors. effects of estrogen, androgen, and progesterone in- (b) Thirty-eight normal females (2 pregnancies). jected singly or in combination. 1 An attempt has been (c) Six castrated females and 6 normal males. made to duplicate on tumors the effect of progesterone (d) Twelve castrated males. acting synergistically with estrogen on either the duct Group/.--Four white female Wistar rats each with or alveolar system, or both, of the mammary gland one spontaneous mammary fibroadenoma. These ani- in early pregnancy. mals had littered from 3 to 5 times, and in two (R 2479 and R 2489) the tumors appeared during the last EXPERIMENTAL pregnancy. In one of these (R 2479) autotransplants were introduced into both axillae and the right groin, Intact and castrated male and female rats with the primary tumor being left in situ in the left groin. spontaneous benign tumors or auto- or homotrans- Two mgm. of dimenformon (a-estradiol) were in- plants were injected with progesterone. Some were jected in divided doses during 3 weeks. The primary treated with estrogen previously, some simultaneously, fibroadenoma and the autotransplants grew rapidly and some received only progesterone. Two pregnant in the next 2 weeks, becoming adenomas, and the rats with benign tumors were also given progesterone. nipples became prominent. At the end of this time, The total dosage varied between 9 and i8 mgm. of pro- i8 mgm. of progesterone were injected subcutane- gesterone and i to 2. 5 mgm. of estrogen. Sixty rats ously in divided doses during the next 9 weeks. Inter- were used, including 4 with spontaneous tumors and val biopsies showed a gradual recession of the tumors 2 pregnant ones. and a shrinkage of their ducts and glands, with in- Before injections of estrogen or progesterone were creasing fibrosis in the stroma. An additional I mgm. begun 4 Wistar rats of our laboratory strain and bear- of estradiol restored their growth rate and they now ing spontaneous tumors were inoculated with auto- showed microscopically a decided duct hyperplasia. transplants. This gave an opportunity to study 3 to 4 At this stage 15 mgm. of testosterone propionate, in- growing or receding tumors of similar morphology jected subcutaneously in divided doses during 8 weeks, in one rat. In these 4 rats there were available r2 again caused recession with the microscopic appear- autotransplants of the first generation, 6 of the sec- ance of epithelial necrosis. The ovaries and thyroid ond generation, and 2 of the third. In this way the were involuted, the adrenals and pituitary decidedly aging of the tumor was slowed, and observation could enlarged. A hydrosalpinx of the right tube was present. be carried out on small tumors instead of on bulky In the second rat (R 2489) with a spontaneous ones (9). tumor and autotransplants 13 mgm. of progesterone were injected in 3 weeks. The primary tumor gradu- Presented at the Endocrine-Cancer Conference, Atlantic City, ally diminished in size, grew harder, and showed in- June 5, i942. volution of the glands and ducts (Figs. I and 2). The * Dimenformon benzoate was generously supplied by Roche- autotransplants did not grow. Injection of i mgm. of Organon, Inc., Nutley, N. J.; progesterone and testosterone by a-estradiol, after a second autotransplantation, stimu- Ciba Pharmaceutical Products, Inc., Summit, N. J., Roche- Organon, Inc., Nutley, N. J., and Schering Corporation, Bloom- lated the growth of the primary tumor and autotrans- field, N. J. plants after 6 weeks (Fig. 3). When the growth was 65

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Downloaded from cancerres.aacrjournals.org on September 26, 2021. © 1943 American Association for Cancer Research. Heiman--Effects of Progesterone on Benign Mammary Tumors 67 established, the injection of Io mgm. of testosterone Group HI.--In 6 castrated females and 6 normal propionate again caused a recession of the tumors. males the injection of progesterone was ineffective. Alternating the injections of progesterone and testos- The few growing tumors were fibromatous, and the terone with estradiol produced further inhibition or takes were reduced to 16 per cent. It had been pre- stinmlation of the primary tumor and the auto- viously reported that the administration of estrogen transplants. to female castrates restored the tumor takes to 54 per In 2 rats, each with a spontaneous and autotrans- cent, and that the transplanted tumors remained fibro- planted fibroadenoma, receiving only progesterone, adenomas (7)" the tumor remained stationary but involution of the Group 1g.--In 6 castrated males the transplanted glandular fraction was apparent. Autotransplants did tumors likewise became fibromas after the injection not grow. of 13 mgm. of progesterone. The fibroadenomas

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(;~oup ll.--(a) Eightcc,~ females with homotrans- usually became more glan(tular in untreated castrated planted fibroadcnoma were iniectcd with 2.S mgm. males (6, 7) and frequently tormcd adcnomas when of cstradiol followed by 18 mgm. of progesterone. the male castrate was given estrogen. In this group thc effect of the estrogen on the benign In groups llb, III, and IV the tumors werc much tumors was evidcnt, but therc appeared to be no smaller and hardcr, and the latent period was pro- enhancing effcct from the progesterone. The per- longed beyond 6 weeks. The action of progesterone centage of takcs approximated the normal (66 per on these growths resembled that of testosterone pro- cent). pionate on similar ones, and appeared to be indif- (b) Twenty females with homotransplanted fibro- ferent or antagonistic to the action of estrogens. It adenoma received 13 mgm. of progesterone each. In required considerably larger doses of progesterone, this group, the growth rate of the tumors was reduced as it did ot~ testosterone, to overcome the action of (22 per cent) and most of them became cellular estrogen. fibromas except in the 2 pregnant females, where the Involution of the tumors, with regression and ne- implanted fibroadenomas remained unchanged. crosis of the glands and ducts and an increased ten-

Downloaded from cancerres.aacrjournals.org on September 26, 2021. © 1943 American Association for Cancer Research. 68 Cancer Research dency toward fibrosis, resulted when from IO to 15 glandular component of these tumors. This action mgm. of testosterone propionate were administered in resembles one noted after the administration of testoste- addition to progesterone. The number of takes in rone to rats with similar tumors. normal females was then reduced to 8. 3 per cent. In 12 Wistar females inoculated with spontaneous fibroade- CONCLUSIONS noma from a Wistar rat that had received progesterone, I. Progesterone inhibited the growth of the ade- no growths resulted nomatous portion of spontaneous rat mammary fibroadenoma. Shrinkage was followed by fibrosis, DISCUSSION 2. Progesterone reduced the percentage of takes of The observations recorded here conform to some auto- and homotransplants (66 to 22 per cent). reports in the literature and are at variance with others. 3- Eighteen mgm. of progesterone did not interfere Thus Corner (2) reported that progestin, injected with the stimulating effect of 2. 5 mgm. of estrogen. into spayed rabbits, does not induce proliferation of Eighteen mgm. of progesterone inhibited the stimu- the mammary gland. Turner and Frank (2o) con- lating effect of i mgm. of estrogen. firmed these findings in castrated male rabbits after 4" Progesterone alone did not affect fibromas grow- estrogen followed by progestin. Turner and Schultze ing in castrated females or normal males. (22) found that stimulation of the mammary lobules 5. Progesterone alone inhibited growth of the glan- did not occur in immature male and female castrated dular portion of adenofibromas in castrated males. rats after luteal extracts were administered. Selye, 6. Progesterone and testosterone in combination Brown, and Collip (18) noted no effect in castrated were effective in reducing the percentage of takes females. Turner and Gomez (2i) found progestin from 66.6 to 8. 3 per cent, and in inhibiting the growth ineffective in stimulating growth. Nelson (14) modi- of the glandular fraction of the tumor. fied his conclusion, at first (17) reporting stimulation 7- Large doses of progesterone or testosterone were and later (i5) obtaining negative results from purified necessary to neutralize the stimulating effect of estro- progestin. Lipschiitz and Vargas (Ii, i2) described gen on growing fibroadenoma. the prevention of experimentally produced uterine 8. Rat fibroma, myxoma, and sarcoma were not and extrauterine fibroids by the injection of testoster- inhibited by progesterone. one and progesterone in guinea pigs. Nelson and 9. Progesterone did not hinder the growth of fibro- Pfiffner (I6) elicited notable hypertrophy of the mam- adenomas in pregnant rats, no doubt because of the mary glands of immature castrated guinea pigs and high estrogen content of the organism. male rabbits by injection of corpus luteum extract. io. The action of progesterone on benign mammary Hartman and Speert (5) produced development of fibroadenomas was unlike the progestational effect on the mammary gland in castrated female monkeys the uterus and normal mammary gland. after large doses (I5O to 500 mgm.) of progesterone. Gardner and Hill (3) found that progestin stimu- REFERENCES lated duct growth in male and female mice. Astwood i. AsTwooo, E. B., and GESCHICKTER, C. F. Changes in the and Geschickter (i, 4) noted on effect on the mam- Mammary Gland of the Rat, Produced by Various mary glands of rats after the administration of pro- Glandular Preparations. Arch. Surg., 36:672-697. 1938. gesterone. 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9. HE1MAN, J., and KRrHBIEL, O. F. The Influence of Hor- I7. NELSON, W. 0., and PFIFFNER, J. J. Studies on the mones on Breast Hyperplasia and Tumor Growths in Physiology of Lactation. I. The Relation of Lactation to White Rats. Am. J. Cancer, 27:45o-473. 1936. the Ovarian and Hypophyseal Hormones. Anat. Rec., lO. KORENCHEVSKY, V., and HALL, K. The Effect of Proges- 5I:5I. 1931. terone on the Metaplasia of the Uterine Epithelium of i8. SrLVE, H., BROWNE, J. S. L., and COLLIE, J. B. Effect of Rats Injected with Oestrogens. J. Obst. & Gynaec. Combined Administration of Oestrone and Progesterone Brit. Emp., 45:22-29. I938. in Adult Ovariectomized Rats. Proc. Soc. Exper. Biol. I i. Lmsu/2rz, A., MURmLO, R., and VAkGAS, L., JR. Anti- & Med., 34:198-2oo. 1936. tumorigenic Action of Progesterone. Lancet, 2:42o-42i. 1939. 19. SMITH, ]. T., and WERrIqESSEN, N. T. Chorioepithelioma I2. Lmscu0Tz, A., and VAROAS, L., Jr<. Prevention of Experi- Associated with Tubal Pregnancy and Pulmonary Metas- mental Uterine and Extrauterine Fibroids by Testosterone tases. High Gonadotropin and Low Pregnanediol Values. and Progesterone. Endocrinology, 28:669-675. 1941. Am. J. Obst. 8: Gynec., 4I:I53-I56. 194I. 13. LYoNs, W. R., and McGINTr, D. A. Effects of Estrone and 2o. TURXER, C. W., and FRANK, A. H. The Relation between Progesterone on Male Rabbit Mammary Glands. I. the Estrus-Producing Hormone and a Corpus Luteum Varying Doses of Progesterone. Proc. Soc. Exper. Biol. Extract on the Growth of the Mammary Gland. Science, & Med., 48:83-86. i94 I. 78:295-296. I931. I4. NELSON, W. O. Endocrine Control of the Mammary Gland. 2I. TURNER, C. W., and GOMEZ, E. T. The Experimental De- Physiol. Rev., 16:488-526. 1936. 15. NELSON, W. O. Studies on the Physiology of Lactation. velopment of the Mammary Gland. I. The Male and the VI. The Endocrine Influences Concerned in the Develop- Female Albino Mouse. II. The Male and the Female ment and Function of the Mammary Gland in the Guinea Pig. Missouri Agr. Exper. Sta. Research Bull., Guinea Pig. Am. J. Anat., 6o:341-359. 1937. No. 2o6. I934. 16. NELSON, W. O., and PEIEI;NrR, J. J. An Experimental 22. TURNER, C. W., and SCHULTZE, A. B. A Study of the Study of the Factors Concerned in Mammary Growth Causes of the Normal Development of the Mammary in Milk Secretion. Proc. Soc. Exper. Biol. & Med., Glands of the Albino Rat. Missouri Agr. Exper. Sta. :28:1-2. 193o. Research Bull., No. I57. I93 I.

Downloaded from cancerres.aacrjournals.org on September 26, 2021. © 1943 American Association for Cancer Research. Comparative Effects of Estrogen, Testosterone, and Progesterone on Benign Mammary Tumors of the Rat

Jacob Heiman

Cancer Res 1943;3:65-69.

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