Adrenal Imbalance in Mouse Skin Carcinogenesis

Summary The influence of adrenal hormonal imbalance on separate stages of skin carcinogenesis was investigated in SWR mice, with a single feeding of 7,12-dimethylbenz[ a ]-anthracene given as initiating stimulus and twice-weekly paintings of 5 per cent croton oil to the skin, for 20 weeks, as promoting stimulus. An excess of hormonal action was achieved by the addition of hydrocortisone to the standard diet, and a deficiency by bilateral adrenalectomy (with reimplantation of isologous adrenal tissue at the end of the required period). The initiating phase of skin carcinogenesis remained unchanged by hydrocortisone feeding or by adrenalectomy, the resulting tumor incidence being 77 per cent in the control animals, 76 per cent in the hydrocortisone-fed animals, and 69 per cent in the adrenalectomized animals (the tumor yields per animal being 2.0 ± 0.2, 1.3 ± 0.2, and 1.2 ± 0.3, respectively). The promoting phase of skin carcinogenesis, on the other hand, was strikingly inhibited by hydrocortisone feeding and strongly enhanced by adrenalectomy, the tumor incidence being reduced to 11 per cent (0.14 ± 0.07 per animal) in the former, and raised to 100 per cent (3.5 ± 0.8 per animal) in the latter. The implication of these results, in the light of the two-stage mechanism of carcinogenesis and in relation to the known effects of glucocorticoid hormones on skin physiology, is discussed.