Stimulation of14C-Cyclic AMP Accumulation by FSH and LH in Testis from Mature and Immature Rats1

Abstract

The stimulatory effects of FSH and LH upon ¹⁴C-cyclic AMP (cAMP) accumulation in “total” testis tissue and isolated seminiferous tubules from weanling, weaned and sexually mature rats were studied. Adenylate cyclase activity was evaluated by measuring ¹⁴C-cAMP formed from endogenous ATP pools prelabeled with 14Cadenine, in the presence of a phosphodiesterase inhibitor. The effects of aminophylline, papaverine or 1-methyl, 3-isobutylxanthine (MIX) on basal and hormone-stimulated ¹⁴C-cAMP accumulation were compared. MIX was found to be more effective than aminophylline or papaverine in enhancing FSH- and LH-evoked accumulation of ¹⁴C-cAMP. In weanling rats a significant FSH effect was found with all of the phosphodiesterase inhibitors employed. In older rats a conclusive and reproducible FSH effect was detected only with MIX. The FSH-responsive adenylate cyclase appears to be located in the cellfs) of the seminiferous tubules while the LH-responsive adenylate cyclase is in the interstitium. These adenylate cyclase systems exhibit selectivity either to FSH or LH.(Endocrinology94: 1028, 1974)