Failure of short-term hyperprolactinaemia to increase the number of gonadotrophin receptors in the ram testis.

Hyperprolactinaemia was induced during March in 2-year-old rams which had regressed testes. Five animals were intravenously infused with prolactin for 3 days at a rate that raised concentrations of prolactin in plasma to levels equivalent to those generally found in summer. Five untreated animals acted as controls. The treatment did not change plasma levels of LH and FSH and had no effect on testicular content of LH and FSH receptors. These results indicate that prolactin is not directly involved in the acute regulation of gonadotrophin receptors in the ram testis.