Effects of hyperprolactinemia on activities of 17-hydroxylase, 17β-ol-dehydrogenase and 5α-reductase in neonatally grafted and host testes in mice

Abstract

Male and female (WB × C57BL/6)F 1 hybrid mice were used. Two pituitaries from 60–80-day-old female mice were grafted under the capsule of the left kidney of 60–80-day-old male mice. One week after grafting, 2 testes from neonatal mice were grafted under the capsule of the right kidney of the grafted mice and 70–90-day-old intact male mice. The grafted and host testes, in groups of 10–26, were removed 15, 30, 40, 60 and 120 days after transplantation of the neonatal testes. Testicular homogenates were incubated with [ 3H]progesterone or [ 14C]4-androstene-3,17-dione, and enzyme activities per g tissue were estimated. Significantly elevated prolactin levels, slightly lower LH levels and normal testosterone levels were found in the mice with pituitary grafts, compared with those in the mice without pituitary grafts. Activities of 17-hydroxylase and 17gb-ol-dehydrogenase increased clearly with age in the grafted testes in the mice without pituitary grafts, though the increases were inhibited significantly by the pituitary grafts. However, the pituitary grafts had no significant effect on activities of 17-hydroxylase and 17β-ol-dehydrogenase in the host testes under similar gonadotrophic stimulation. 5α-Reductase activities in the grafted and host testes were unaffected by the pituitary grafts. These results show that hyperprolactinemia may directly inhibit increases in activities of 17-hydroxylase and 17β-ol-dehydrogenase with testicular age in neonatally grafted testes in mice.