The effects on hepatic steroid metabolism of an ectopic pituitary graft: A time study

The time course of feminization of hepatic steroid metabolism in the rat was followed after transplantation of a normal male or female pituitary gland under the kidney capsule of the host animal. Feminization of enzymes active on 4-androstene-3,17-dione and 5α-androstane-3α, 17β-diol occurred between 4 and 8 days after transplantation. Prior to this, masculinization of liver enzyme activities was seen in the transplanted animals. The data on concentrations of lutropin (LH), follitropin (FSH) and prolactin in host serum indicated that, of these hormones, only prolactin was produced by the ectopic pituitary gland. A lag period of 2–4 days was observed before prolactin appeared in host serum. The serum concentrations of prolactin, lutropin and follitropin were poorly correlated with the degree of feminization of hepatic steroid metabolism in the host animal. It thus appears that the ectopic pituitary gland within 4–8 days after implantation begins to secrete (a) factor(s) which is (are) not identical to prolactin, lutropin or follitropin, and which feminize(s) the steroid metabolism in the liver.