In vitro effects of prolactin and dexamethasone on rat Leydig cell aromatase activity.
In Percoll purified adult rat Leydig cells, the estradiol secretion, in presence of exogenous testosterone (200 ng/ml) is stimulated 2-fold by either LH (100 ng/ml) or dbcAMP (1 mM). The addition of prolactin (1 microgram/ml) or dexamethasone (10(-7) M) to the Leydig cell incubation medium induces a 20% increase of the basal estradiol production, whereas, under LH or dbcAMP stimulations, 46 and 41% decreases are noted; moreover, a synergistic effect between prolactin and dexamethasone was observed in presence of dbcAMP leading to a 53% diminution of the estradiol synthesis. There results suggest that either hyperprolactinemia or high doses of glucocorticoids might inhibit the Leydig cell aromatase activity in presence of LH.
D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology*; D004958:Estradiol / Q000096:biosynthesis; D007985:Leydig Cells / Q000201:enzymology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D011388:Prolactin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D004958:Estradiol; D003994:Bucladesine; D003907:Dexamethasone; D011388:Prolactin; D007986:Luteinizing Hormone; D001141:Aromatase