The Effect of Growth Hormone, Insulin and Alloxan-Induced Diabetes on Carcinogenesis in the Genital Tract of Intact and Castrate Female Rats

Castrate female rats given weekly applications of DMBA to the genital tract and treated additionally with growth hormone, insulin or alloxan (to induce diabetes) are heavier and have more sarcomatous and epithelial cervico-vaginal neoplasms than intact animals under the same experimental conditions. Promotion of carcinogenesis and gain in body weight are independent phenomena caused by castration in the medicated rats. Growth hormone is most effective in enhancing body weight in all animals, but least as regards tumour formation. It reduces the incidence of sarcomas in intacts, but raises that of epithelial neoplasms, and promotes both types of neoplasms in castrates. The highest incidence of cervico-vaginal epithelial and sarcomatous tumours occurs in spayed diabetics. Squamous celled epitheliomas of the vulva are not affected by castration or additional medication, while basal celled neoplasms tend to be more frequent in intacts than in castrates and particularly numerous in intact failed diabetics. Vulval sarcomas are usually rare but are increased in numbers in diabetic and in insulin treated intacts. Granular myoblastomas of the cervico-vaginal tract occur in intacts only and particularly in diabetics and those medicated with growth hormone or insulin.