DIRECT ACTION OF TESTOSTERONE PROPIONATE ON THE RAT MAMMARY GLAND

Abstract

ABSTRACT Testosterone propionate in arachis oil was applied locally to the skin over the third left thoracic mammary gland (= experimental gland) of castrated male and female rats. Arachis oil was applied to the third right thoracic mammary gland (= control gland). After 21–23 days of local applications the development of the experimental and control glands was studied on whole mount preparations. It was found that small doses of testosterone (0.15 mg daily) stimulated slight but definite lobule-alveolar development in the experimental glands, while the control glands did not show any alveoli. Applications of higher doses of testosterone propionate (0.30 and 0.75 mg daily) stimulated extensive lobule-alveolar development in the experimental glands, while only few alveoli were produced in the control glands. It may therefore be concluded that the effect of testosterone on the rat mammary gland is not mediated through other endocrine glands, but is a direct, local effect on the mammary gland structures. The result is discussed in relation to our present knowledge of the hormonal control of different growth processes within the mammary glands.