Sex difference in LH response to LHRH and DBcAMP and effect of 17beta-estradiol.

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Abstract
The effects of luteinizing hormone-releasing hormone (LHRH) and N6,O2''-dibutyryl cyclic AMP (DBcAMP) on luteinizing hormone (LH) release into medium and on cellular LH content were examined in 4 h incubations with pituitary cultures prepared from male or female rats and maintained in medium supplemented with the pooled serum of donor rats. LH release in response to 10 nM LHRH was significantly greater in female rat pituitary cultures (female-RPC) than in male rat pituitary cultures (male-RPC) 8-fold vs. 2-fold of control, respectively. Addition of 10 mM DBcAMP significantly stimulated LH release in female-RPC (2-fold of control) but not in male-RPC. LHRH and DBcAMP significantly increased total LH accumulation (LH contents in medium and cells) in female-RPC but not in male-RPC. In female-RPC maintained in medium supplemented with serum adsorbed with dextran-coated charcoal, 17.beta.-estradiol (E2) pretreatment of augmented LHRH or DBcAMP stimulation of LH release and LH accumulation E2 alone significantly increased cellular LH content, cAMP binding and protein kinase actvities in female-RPC. E2 may contribute to the sex difference in putuitary LH response to LHRH and DBcAMP by increasing both cellular LH content and the activity of the cAMP-effector system in female-RPC.