Abstract
The growth of the mammary glands of males bearing ovarian grafts or receiving extracts of estrogenic hormones has been observed by many investigators. Several pure estrogenic chemicals, theelin, theelol, 1 dihydroestrin and equilin, 2 , 3 induced the growth of the mammary glands of male mice and of males of other species. The male hormone, testosterone, also induced a limited mammary gland proliferation in rats. 4
Progestin had no effect upon the mammary glands of rabbits when injected as a rather crude extract, 5 , 6 but when progestin and theelin were administered simultaneously a complete development of the mammary glands occurred. 7 The mammary ducts developed in rabbits receiving estrin, while simultaneous injections of progestin and estrin induced the development of the lobules of alveolar tissue as observed during pregnancy or pseudo-pregnancy. In some strains of mice scattered lobules of alveoli developed in males receiving large amounts of estrogenic hormone 8 while a complete development of the lobules occurred in injected males from other strains. 9
The mice used in this investigation were supplied by Dr. L. C. Strong. Two highly purified extracts of progestin obtained from corpora lutea† ‡ and one crystalline preparation of progesterone (Proluton)§ were used. All of the preparations were dissolved in oil and were injected subcutaneously.
Seven castrated male mice were given from 0.35 to 1.6 units of progestin† over periods of from 14 to 16 days. Two of these mice were given in addition 5 rat units of theelin daily. The mammary rudiments of all of these mice had developed into extensive systems of branching ducts, similar to those of mice receiving theelin for approximately 30 days. One castrated male receiving 5 r.u. of theelin daily showed but a slight growth of the mammary glands. One of two non-castrate male mice receiving 0.1 unit of progestin daily for 14 days showed extensive development of the mammary ducts.
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