Stimulation of catecholamine synthesis through unique estrogen receptors in the bovine adrenomedullary plasma membrane by 17β-estradiol

Incubation of cultured bovine adrenal medullary cells with 17β-estradiol (E2) (0.3–100 nM) or membrane-impermeable E2-bovine serum albumin (100 nM) acutely increased 14C-catecholamine synthesis from [14C]tyrosine. The stimulatory effect of E2 was not inhibited by ICI182,780, a nuclear estrogen receptor inhibitor. E2 also increased tyrosine hydroxylase activity and p44/42MAPK phosphorylation, the former of which was attenuated by U0126, an inhibitor of p44/42MAPK kinase. The plasma membrane isolated from the gland showed two classes of specific binding sites of [3H]E2 with apparent Kds of 3.2 and 106 nM, and Bmaxs of 0.44 and 8.5 pmol/mg protein, respectively. The high-affinity binding of [3H]E2 was most strongly inhibited by E2 and phytoestrogens, and to lesser extents by other steroid hormones, while it was enhanced by ICI182,780 and environmental estrogenic pollutants. These findings suggest that E2 acutely stimulates catecholamine synthesis via activation of p44/42MAPK through unique estrogen receptors in the plasma membrane of bovine adrenal medulla.