THE EFFECTS OF THE SYNTHETIC AND NATURAL HORMONE OF THE ADRENAL CORTEX ON MELANIN DEPOSITION IN ADRENALECTOMIZED BLACK RATS FED DIETS ADEQUATE AND DEFICIENT IN THE FILTRATE FACTORS OF VITAMIN B1

Abstract

In a previous study the stimulating effect of adrenalectomy on hair growth and melanin deposition in black rats fed filtrate factor deficient diets or diets supplemented with a rice bran extract, was reported. In the present study, the role of the adrenal cortex was further investigated by administering either the natural or the synthetic hormone of the adrenal cortex to rats following adrenalectomy. The rats were placed for 30 days on filtrate factor deficient diets and were then adrenalectomized. Following adrenalectomy some of the animals were continued on the deficient diet and of these 24 rats received cortin daily (0.4 ml) and the others (43) were given 0.5 mgs of DOCA daily. Both forms of the hormone were given by injn. Of the other groups, 13 rats received the filtrate factors as a rice bran extract and injns. of cortin after adrenalectomy: 13 the rice bran extract and injns. of DOCA daily: and 25 received Ca pantothenate and injns. of DOCA daily. 69 non-operated rats serving as controls were treated as to diet and hormone therapy in a manner identical to the adrenalectomized rats. The results observed were that grossly the diffuse bluing of the skin that is seen following adrenalectomy in black rats was inhibited by the adm. of the synthetic hormone of the adrenal cortex, de-soxycorticosterone acetate (DOCA). The effects of the naturally occurring adrenal cortical hormone were less striking. However, on microscopic examination of skin sections, the inhibiting effects of cortin on hyperplasia of the hair apparatus and on melanin deposition were seen; the inhibiting effects of DOCA were more striking and microscopically there was almost no melanin deposition in the hair follicles or bulbs of these rats and in fact there was a very striking retardation of the usual proliferation of hair buds that usually follows adrenalectomy. In the unoperated control rats, DOCA retarded the deposition of melanin that usually follows the adm. of Ca pantothenate to rats on filtrate factor deficient diets. There was also a retardation of the regrowth of the hair bulbs and follicles. No effect of hormone therapy was seen in normal rats continued on deficient diets, which is logical as such diets cause atrophy of the hair apparatus and a decrease in melanin. The results furnish additional experimental proof of the effect of the adrenal cortex and its hormones on melanin metabolism, confirming the earlier report (Ralli and Graef 1943) of the stimulating effect of adrenalectomy on melanin deposition and hyperplasia of the hair apparatus and showing in addition that this effect can be significantly depressed by the daily adm. of the synthetic hormone of the adrenal cortex, desoxycortico-sterone acetate, and, although to a somewhat lesser extent, also by the naturally occurring cortical hormone.