Effect of pregnancy and diabetes on vascular receptors for angiotensin II.

Both gestation and diabetes mellitus (DM) are conditions associated with an increased participation of renin-angiotensin system (RAS) as well as with changes in the vascular response to angiotensin II (Ang II). We sought to establish the impact of gestational diabetes mellitus (GDM) on Ang II- induced vasoconstriction and its correlation with the expression of angiotensin II receptors (AT(1)R, AT(2) R). Female Wistar rats, virgin, or on day 3 after mating, received randomly streptozotocin (STZ) 60 mg/kgor saline ip.Streptozotocin-treated animals developed hyperglycemia (25.6 ± 1.42 mM). Ang II-induced vasoconstriction was evaluated on isolated aortas with (e+) and without (e-) endothelium and the protein expression of AT(1)R and AT(2)R was measured by western blot. Gestational diabetes mellitus significantly increased vasoconstriction with respect to all the other groups. Changes were observed only on e+ vessels. Interestingly, GDM moved AT(1)R: AT(2)R balance towards AT(1) R, while both pregnancy and diabetes towards AT(2)R expression. In conclusion, GDM increases the possibility of an hypertensive complication by an increased AT(1)R expression.