The Effect of A-Estradiol-3-Benzoate on the Response of CHI Mice to 20-Methylcholanthrene Albert Segaloff, M.S

The Effect of a-Estradiol-3-Benzoate on the Response of CHI Mice to 20-Methylcholanthrene Albert Segaloff, M.S.

(From the Department o/ Anatomy, Wayne University, College of Medicine, Detroit, Mich.) (Received for publication March 23, I942)

The role of estrogenic substances in the production of neo- obtained from Dr. L. C. Strong's colony at Yale Uni- plasms of the male and female genital tracts and of the mam- versity. At Dr. Strong's suggestion they were fed mary glands of both sexes has been discussed at length by many authors. It appears that the conclusions reached depend largely nurishmix pellets supplemented semiweekly with let- upon a number of variables; among these are the criteria of tuce. They were housed in wooden boxes and fed malignancy chosen, the specific estrogen, the route of administra- from hoppers. The mice used for transplantation were tion, and the animals themselves. offspring of additional animals obtained from Dr. However, it would appear from the excellent review of Strong at the same time as the mice which were treated Gardner (I) that the estrogcns really have some effect on the production of mammary, uterine, vaginal, and testicular neo- with estrogen and carcinogen. plasms. Factors which modify this relation betwecn estrogcn The estrogen employed was estradiol benzoate 1 in anti the induction of ncoplasms include the heredity of the sesame oil. The solution contained I mgm. per cc. expcrimental animal, the type of estrogenic substance used, and and the animals were given subcutaneous injections the duration of treatment. In this connection it is interesting to note that some car- of o.o 5 cc. once weekly. cinogenic hydrocarbons are believed to have cstrogenic prop- The carcinogen was 2o-methylcholanthrene." Under erties (4). ether anesthesia 1. 5 to 3.o mgm. pellets were inserted Although these considerations might indicate thc existence subcutaneously in the dorsal region through a small of some rclationship bctween the scx glands and reactions to incision, and the wound was closed with a single silk carcinogcnic hydrocarbons, such has not been thc case. Indeed, Stewart (8) has pointed out that castration secms to have no stitch. significant effect on the carcinogenic action of 1,2,5,6-dibenzan- The mice were observed daily, but tumors were thracene in C3H mice. measured and the dates of their appearance recorded Pierson (5) treated 2 rabbits for I3 months with folliculin at weekly intervals. and tar and noted that one developed a carcinoma and the other an adenoma of the uterus. Gihnour (2) used mixed stock Transplants were made into young adult mice by mice and painted 3,4-benzpyrcnc and estrone on the skin. The injecting a saline suspension of tumor tissue subcu- compounds were dissolved in chloroform. She concluded that taneously with a trocar. estrone increased the susccptibility of the skin to the carcinogen and that it also hastened the appearance of the tumors. Pcrry RESULTS and Ginzton (3) also employed stock mice. They dissolved estrone and ~,2,5,6-dibenzanthracene in benzene and painted As can be seen from Table I there was no essential this mixture, and 1,2,5,6-dibenzanthracenc alone, on the skin. difference in the latent period or in the incidence of There was a higher incidence of tumors in the group receiving tumors whether 2o-methylcholanthrene was given estrone and the carcinogen than in the group recciving the carcinogen alone. alone or in combination with estradiol benzoate. All Recently Smith, Wells, and D'Amour (7) have injected rats tumors arose subcutaneously in the region of the pellet. with 2o-methylcholanthrene in paraffin and with estradiol ben- The first occurred from i2 to 17 weeks after im- zoate in sesame oil. They found that neither castration nor the plantation of the pellets, when the mice were approxi- estradiol benzoate affected the tumor incidence or the latent period of induction. mately 7 months old. The last tumor to appear was first palpable in the :z4th week after pellet implanta- The present work was undertaken because it seemed tion, when the mice were about 9 months of age. desirable to study the possible cocarcinogenic effect of The average latent period for the entire group was estrogens in a pure strain of mice. Furthermore it 18 weeks. was believed that the results of Gilmour (2) and of Histologically :~ all the growths except 2 mammary Perry and Ginzton (3) might result in some measure gland tumors in the untreated group were classed as from the toxic solvent they had used as a vehicle for the estrogen. Accordingly, the following experiment a-Estradiol benzoate was generously supplied as progynon-B was undertaken. by Dr. Erwin Schwenk of the Schering Corporation. e The 2o-methylcholanthrene was prepared by Dr. W. E. MATERIAL AND METHODS Bachmann and supplied through the courtesy of Dr. J. T. Brad- bury of the University of Michigan, Ann Arbor. All the mice used in this study were young adults a I would like to thank Dr. Edgar H. Norris for his interest of the CHI strain, approximately 3 months of age, and for reviewing the microscopic classification of all the tumors. 794

Downloaded from cancerres.aacrjournals.org on October 3, 2021. © 1942 American Association for Cancer Research. Segaloff--~-Estradiol-3-Benzoate and 2o-Methylcholanthrene 795 sarcomas of grade II or III. 4 Four from animals treated present experiment the co- or anticarcinogenic effect with estrogen and carcinogen and 4 from animals of estradiol would be shown only if it were very great, treated with carcinogen only were transplanted through since large amounts of carcinogen were employed. 4 transplant generations. In the first group IIO ani- However, it should be noted that where a cocarcino- mals were used for hosts and ioo in the second. genic effect of estrogen on the skin of the mouse has These sarcomas all grew at about the same rate, took been reported large concentrations of carcinogen have in the same proportion of animals (78 and 82 per cent), been employed also. Our studies, like those os Smith, and retained their histological identity. Those trans- Wells, and D'Amour (7), show no cocarcinogenic planted were used when they had reached 1. 5 cm. in effect of estrogens on the connective tissue, subject, their greatest diameter. In all other cases animals with of course, to the conditions of the experiment.

TABLE I: OCCURRENCE OF SARCOMAS IN CHI MICE TREATED WITH ESTROGEN AND CARCINOGEN Average Number Latent period, latent Total alive at Number of 1st tumor, period, Incidence * Treatment Sex number ist tumor tumors weeks weeks per cent EB, MC M 25 I7 I4 15 17 82 F i2 8 6 16 19 75 Both 37 25 20 15 "~ ~8 8o EB M 25 -- o -- -- F 12 -- o -- -- Both 37 o MC M 25 20 15 i 2 15 75 F 12 9 5 17 2o 55 Both 37 29 20 14 T I8 69

None M 25 -- 0 F 12 O Both 37 -- EB ~ 5o'y a-estradiol-3-benzoate in o.o5 ee. sesame oil once weekly. klC ~ Pellet of 2o-methylcholanthrene (~.5 to 3.0 mgm.) subcutaneously. Percentage of animals, alive at time of appearance of ist tumor, which developed tumors before death. Average of males and females. tumors were allowed to live until they were dead or SUMMARY moribund. None of the growths metastasized, but a-Estradiol-3-benzoate had no effect on the inci- practically all infiltrated through the body wall. dence, degree of malignancy, or latent period of tumor Two males, one treated with estradiol benzoate and induction by pellets of 2o-methylcholanthrene in CHI a pellet of 2o-methylcholanthrene and the other with mice. only a pellet of 2o-methylcholanthrene, developed The animals displayed the usual effects of hyper- what appeared in the gross to be neoplasms around the pellets, but on section they were classified as estrinism. inflammatory reactions. No malignant lesions of the cervix or upper vagina Characteristic estrogenic effects were seen in all ani- were observed in any of the animals. mals which received estradiol benzoate. These in- I wish to thank Dr. Warren O. Nelson, Chairman of the cluded resorption of the pubic symphyses in the Department of Anatomy, for encouragement and advice through- females, retention of urine and hydronephrosis, sup- out this study and also for allowing me the use of his laboratory. pression of spermatogenesis, and pronounced stimula- tion of the female genital tract. REFERENCES The cervices of all females were sectioned serially I. GARDNER, W. U. Estrogens in Carcinogenesis. Arch. Path., and studied. In no instance did they show changes 27:138-17 ~ . I939. which could be considered malignant. 2. GILMOUR, M. D. An Investigation into the Influence of Oestrone on the Growth and on the Genesis of Malignant DISCUSSION Cells. J. Path. & Bact., 48:179-188. 1937. From the results reported by Shear and his associates 3. PERRY, I. H., and GINZTON, I.. L. The Development of (6) it is possible that under the conditions of the Tumors in Female Mice Treated with 1:2:5:6-Dibcnzan- thracene and Theelin. Am. J. Cancer, 29:68o-7o 4. 1937. 4 Tumors were graded histologically into four groups on the 4- PERRY, I. H. Estrogenic Activity of 3-4 Benzpyrene. Proc. basis of differentiation and anaplasia. Soc. Expcr. Biol. & Med., 39:346-347. 1938.

5" PIERSON,H. Experimentelle Erzeugung yon Uterusgeschwfils- 7. SMITH, D. L., WELLS, J. A., and D'AMouR, F. E. The Rela- ten bei Kaninchen durch Ovarialhormone. Ztschr. f: tionship of the Endocrine System to Carcinogenesis. Krebsforsch., 41:1o3-138. x935. Cited by Perry and Cancer Research, 2:4o-44. I942. Ginzton (3)- 6. SALL, R. D., and SI-IZAR, M. J. Studies in Carcinogenesis. 8. STEWART, H. L. Influence of Castration on the Induction of XII. Effect of the Basic Fraction of Creosote Oil on the Subcutaneous Tumors in Mice of the C3H Strain by Production of Tumors in Mice by Chemical Carcinogens. I:2:5:6-Dibenzanthracene. Pub. Health Rep., 54:1o26- J. Nat. Cancer Inst., 1:45-55- I94O. lO31. 1939-

Downloaded from cancerres.aacrjournals.org on October 3, 2021. © 1942 American Association for Cancer Research. The Effect of α-Estradiol-3-Benzoate on the Response of CHI Mice to 20-Methylcholanthrene

Albert Segaloff

Cancer Res 1942;2:794-796.

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