The effect of estradiol on urodilatin production in postmenopausal women

Urodilatin, which is structurally homologous to atrial natriuretic peptide, is most probably synthesized in the kidney. It inhibits water and sodium reabsorption and causes renal vasodilatation. However, little is known about the regulation of its synthesis, especially with regard to the influence of hormones. Transdermal administration of estradiol with low dosage producing physiologic conditions, and oral administration of estradiol with high pharmacologic dosage were investigated for their effect on urodilatin production in postmenopausal women measuring urinary excretion. Both routes of administration of estradiol increased urodilatin excretion after 28 days of treatment, the increment being statistically significant only for the transdermal route. The increased urodilatin production registered after transdermal estradiol replacement therapy may suggest that estradiol has a vasodilatory effect on the kidney.