3H-PGE1 binding and production of cAMP and testosterone by Leydig cells during adolescence in rats

3H-PGE1 binding capacity of Leydig cells isolated form the testes of rats aged 25 to 120 days was studied together with in vitro responsiveness of cAMP and testosterone synthesis to PGE1. It was demonstrated that the specific binding of 3H-PGE1 by rat Leydig cells increased with age up to the 50th day and then gradually decreased. The changes in binding capacity of 3H-PGE1 did not correlate with the responsiveness of Leydig cells to PGE1 in cAMP and testosterone production during postnatal development, though this stimulatory effect of PGE1 was significant during the whole period studied. Finally, in vivo administration of PGE1 increased the production of testosterone by testes and also the level of this hormone in blood.