The Influence of Testosterone Propionate on Pigmentation of the Mammary Nipples in Female Mice

Abstract

In recent experiments on the influence of testosterone propionate on tumours induced by carcinogens, a striking pigmentation of the mammary nipples in female mice of several strains was observed. The nipples were easily visible against the brighter background of the abdominal coat, while they were hardly noticeable in the untreated mice of the same strains. In previous experiments [Flaks & Ber, 1938, 1939a, in which albino mice were treated with very large doses of testosterone propionate, these changes were not noticed, although the mice were maintained for a period of nearly 12 months.It is known from earlier work that injections of oestrogens in guinea-pigs and humans induced hyperpigmentation of the nipples [Lipschutz ]. Local application of oestrone and stilboestrol was also shown to cause hyperpigmentation of the nipples in male guinea-pigs [Fierz, 1939].The influence of androgens on pigmentation was reported by Hamilton & Hubert [1938]: the skin in castrated men, which is generally pale, became darker after treat¬ ment with androgenic hormones. Edwards, Hamilton, Duntley & Hubert [1941] found that the melanin content of the skin in eunuchs is subnormal. Treatment with androgens resulted in an increase of the pigment. Forbes [1942] described hair cha ages and pigmentation of the mammary nipples in rats with implanted pellets of sex hormones. In these experiments a number of oestrogens and androgens were employed. All the oestrogens, but only androsterone among the androgens, caused a partial pigmentation of the fur of albino rats and alopecia in dark grey-brown rats.Testosterone propionate and dipropionate, and androsterone, did not induce pigmenta¬ tion of the nipples. In addition, a few rats of the albino and dark grey-brown strains with diethylstilboestrolmethyl-ether pellets showed either black pigmentation of the capsule around the pellet or similar changes in the male mammary gland. Kirshbaum & Pfeiffer [1941] showed that local application of testosterone propionate induced deposition of melanin in the bill of the sparrow. MATERIAL AND METHODSOne hundred and eighty mice of four strains were employed in the experiments: CBA-black agouti, C3H-dark grey-brown, Strong -albino and mixed stock (black, brown and albino). All mice were virgins, about 3 months old, except two breeding C3H mice which were approximately 12 and 17 months old. Seventy mice were injected, under the skin of the abdomen, with a 2-5% solution of testosterone propionate in arachis oil. Each mouse received weekly injections of 6-25 mg. of * Bertram Parkinson Research Fellow.

The Influence of Hormones on Melanogenesis

“…The action of androgens on melanogenesis is both complex and illnnderstood. According to a number of experimental variables androgens may stimulate (Hamilton and Hubert, 1938;l'](lwards ct at., 1941;Ivui)permaun, 1944;Flaks, 1948), inliibit (Bischitz and Snell,19r)9) oi-fail to influence the melanin content of the skin (Snell, 1967). It appears that in general androgeus increase pigmentation in the human ,skin although the extent to Avhich this response is the result of a direct influence ou the melanocytes or tlie result of au action upon the vascular supply to the skin, remains unkuoAvn (Hamilton, 1939).…”