Adenylate cyclase in human ovarian cancers: sensitivity to gonadotropins and nonhormonal activators

Adenylate cyclase activity in particulate preparations of ovarian tumors from 47 women was determined by measuring the conversion of phosphorus 32-labeled adenosine triphosphate to phosphorus 32-labeled cyclic adenosine monophosphate. Ovarian cancers typically exhibited an active adenylate cyclase which was stimulated by 50 mumol/L 5'-guanylylimidodiphosphate and 10 mmol/L of sodium fluoride. This activity was comparable to that in particulates of normal postmenopausal ovaries and was independent of the class of tumor. There was no significant increase in adenylate cyclase activity in any epithelial or germinal tumor in the presence of either 250 nmol/L of human chorionic gonadotropin or 333 nmol/L human follicle-stimulating hormone. However, cyclic adenosine monophosphate production by two sex cord stromal tumors was stimulated by follicle-stimulating hormone, but not by human chorionic gonadotropin. Follicle-stimulating hormone stimulated a threefold increase in activity in the granulosa-theca cell tumor, with an activation constant (57 nmol/L) similar to that in follicle-stimulating hormone-responsive rat ovaries. Prostaglandin E1 (50 mumol/L) increased cyclic adenosine monophosphate production by epithelial tumors more than twofold. These data suggest that sex cord stromal tumors, unlike the more common epithelial tumors, can be modulated directly by gonadotropin.