The inhibition of progesterone secretion and the regulation of cyclic nucleotides by atrial natriuretic factor in gonadotropin responsive murine Leydig tumor cells

Abstract

We have found that atrial natriuretic factor (ANF) has a profound effect on testicular cells in altering intracellular cyclic nucleotide levels as well as progesterone secretion. Using clonal cultured Leydig tumor cells we found that 1 X 10(-8)M ANF caused a two thousand-fold elevation in the accumulation of cellular cGMP and inhibited cAMP in treated cells by more than 90% as compared to the controls. ANF (1 X 10(-8)M) also significantly inhibited gonadotropin-stimulated accumulation of cAMP in response to bovine luteinizing hormone (bLH) or human chorionic gonadotropin (hCG). Gonadotropin-stimulated progesterone secretion was inhibited by ANF (1 X 10(-10) - 1 X 10(-9)M) in these cultured Leydig tumor cells. Approximately 50% inhibition of progesterone secretion was observed at the peptide concentration of 1 X 10(-9) M.