INTERACTION OF ANGIOTENSIN-II AND BRAIN NATRIURETIC PEPTIDE IN THE PLACENTAS OF NORMAL AND DIABETIC WOMEN

Objective: To evaluate the effects of angiotensin II and brain natriur etic peptide on the placental vasculature of diabetic women. Methods: Term placentas from five diabetic women and five nondiabetic controls were collected. Isolated placental cotyledons were perfused dually wit h fetal perfusion pressure as an index of vascular response. The effec t of angiotensin II (10(-10)-10(-5) mol/L bolus injection) was establi shed in the fetal-placental vasculature of all placentas in the absenc e or presence of brain natriuretic peptide (10(-8) mol/L final concent ration). Data were analyzed using repeated measures analysis of varian ce and paired t test where appropriate. Results: A significant vasocon strictor response to angiotensin II was achieved in placentas of both diabetic and nondiabetic women (P < .001); however, the angiotensin II -induced increase in perfusion pressure was significantly greater in t he diabetic group (P < .01). Significant attenuation of vasoconstricto r response to angiotensin occurred in the presence of brain natriureti c peptide in placentas of both nondiabetic (P < .0025) and diabetic (P < .025) women, but the effect was more prominent in the diabetic grou p. Conclusion: The in vitro placental vasculature of diabetic women is more sensitive to angiotensin II than is the in vitro placental vascu lature of nondiabetic women. The attenuation exerted by brain natriure tic peptide on angiotensin II-induced vasoconstriction is more promine nt in placentas from diabetic women compared to those from nondiabetic women.