Timing and Localization of the Stimulatory Effect of Follicle-Stimulating Hormone on Uridine Incorporation in the Mouse Testis in Vivo

Abstract

Human pituitary FSH increased the incorporation of [5-(3)H]uridine into RNA in vivo in the testes of intact 9-day-old mice and of hypophysectomized adults. In both groups the effect was greatest 8 h after administration of 5--7.5 i.u. FSH. Autoradiographs were prepared from the testes of hypophysectomized adult mice given subcutaneous injections of FSH or of 0.9% saline 6 h, and [5-(3)H]uridine 1.5 h, before death. Treatment with FSH caused statistically significant increases in the density of silver grains over the nuclei of Sertoli cells, type A and intermediate spermatogonia, and preleptotene and mid-pachytene primary spermatocytes. It was concluded that FSH has a generalized stimulatory action on RNA synthesis in the nuclei of Sertoli cells and those types of germinal cell which synthesize RNA most actively.

Nucleoside Transport at the Blood-Testis Barrier Studied with Primary-Cultured Sertoli Cells

“…Rat testis has a high activity of hypoxanthine-guanine phosphoribosyltransferase and uridine kinase, rate-limiting enzymes of the purine and pyrimidine salvage pathways, respectively (Adams and Harkness, 1976;Haugen et al, 1988). Nucleoside incorporation into DNA or RNA in testis was observed by autoradiographic study (Monesi, 1962;Davies and Lawrence, 1981). Labeling with 5-bromodeoxyuridine, a pyrimidine analog, was found exclusively in the nuclei of rat Sertoli and spermatogenic cells after intraperitoneal injection of 5-bromodeoxyuridine (Shirataki et al, 1994).…”