Prostaglandins inhibit testosterone secretion by mouse testes in vitro.

Production of testosterone (T) by decapsulated mouse tests in vitro was significantly inhibited by adding prostaglandin (PG) A1, PGA2 or PGE1 to the incubation medium. Prostaglandin A1 at a concentration of 10(-6)M inhibited T production in this system both in the presence of moderate amounts of hCG (12.5 or 25.0 mIU/ml), and in the absence of gonadotropins. However, in the presence of very high levels of hCG (125.0 mIU/ml), all PGs tested appeared to have had a slight potentiating effect on T production when added in concentrations ranging from 10(-7) to 10(-5)M, and the inhibition of T accumulation in the medium was consistently observed only when the concentration of PGs was increased to 10(-3)M. These results suggest that a direct effect of PGs on testicular steroidogenesis may account for, or contributes to, the decrease in peripheral T levels observed after administration of PGs in vivo.