Differential effect of cyclic adenosine monophosphate on the secretion of human placental lactogen and human chorionic gonadotropin.

In human placental explants cultured in vitro, 1 mM dibutyryl cyclic AMP and 1 mM theophylline alone or in combination markedly stimulated the secretion of human chorionic gonadotropin (hCG) into the medium but had no effect on the secretion of human placental lactogen (hPL). These results indicate that 1) cyclic AMP can modulate the secretion of hCG, and 2) the intracellular control mechanisms regulating the secretion of hCG and hPL from the syncytiotrophoblast may be different.