A novel role for an endothelial adrenergic receptor system in mediating catecholestradiol-induced proliferation of uterine artery endothelial cells.

Sequential conversion of estradiol-17β to its biologically active catecholestradiols, 2-hydroxyestradiol (OHE(2)) and 4-OHE(2), contributes importantly to its angiogenic effects on uterine artery endothelial cells (UAECs) derived from pregnant, but not nonpregnant ewes via an estrogen receptor-independent mechanism. Because catecholestradiols and catecholamines exhibit structural similarities and have high affinity for α- and β-adrenergic receptors (ARs), we investigated whether the endothelial α- or β-ARs mediate catecholestradiol-induced proliferation of P-UAECs and whether catecholamines alter these responses. Western analyses revealed expression of specific AR subtypes in nonpregnant UAECs and P-UAECs, including α(2)-, β(2)-, and β(3)-ARs but not α(1)- and β(1)-ARs.