Effect of hypophysectomy and pituitary implants at puberty on the sexual differentiation of testosterone metabolism in rat liver.

The role of the pituitary in the sexual differentiation of the Δ4-3-keto reduction of testosterone in th e rat liver was investigated. Testosterone-1,2-H3 was incubated in liver slices under nitrogen and the sexually dimorphic pattern of the metabolites 3α,17β-dihydroxy-5β-androstane (A), 3β, 17β-dihydroxy-5α-androstane (B), 3α, 17β-dihydroxy-5α-androstane (C) and 5α-dihydrotestos-terone (D) was studied. Male rats, gonadectomized at 25 days of age, formed as adults higher amounts of A and B and lower amounts of C and D than gonadectomized female rats. Hypophysectomy at 25 days of age abolished the development of these sex differences. Compared to gonadectomized females, hypophysectomized rats produced high levels of A and B and low amounts of C and D, which is a shift to a male-type of metabolism. Implantation of a male or female pituitary under the kidney capsule in gonadectomized-hypophysectomized rats did not restore sexual differentiation of metabolism but resulted in a decrease of A and B and a large...