Estrogen upregulates renal angiotensin II AT 1 and AT 2 receptors in the rat

Abstract

We studied renal AT 1 and AT 2 receptors in male, female, ovariectomized and ovariectomized-estrogen-treated Wistar–Hanover and Wistar–Kyoto rats. AT 1 receptors and AT 1A receptor mRNA predominated, with no significant differences between males and females. AT 2 receptor expression was restricted in female rats to the capsule, the transition zone between outer and inner medulla, the endothelium lining the papilla, and arcuate arteries and veins. There were no AT 2 receptors in male rats, while male mice express substantial numbers of estrogen-dependent AT 2 receptors. Arcuate arteries and veins expressed AT 1B mRNA in males and females, and AT 2 mRNA in females only. AT 1 receptor and AT 2 receptor expression were estrogen-dependent, with increases in AT 1 and AT 2 receptor expression after estrogen treatment in ovariectomized rats. Estrogen treatment increased prostaglandin E 2 (PGE 2) and cGMP concentrations in the renal medulla, and eNOS expression in cortical arteries. In rodents, expression of renal Angiotensin II receptor types is estrogen-dependent, with significant species, strain and area differences. Our results support an important role for AT 2 receptors in the regulation of renal function and in the protective effects of estrogen in the kidney.