Temporal alterations in vascular angiotensin receptors and vasomotor responses in offspring of protein-restricted rat dams

OBJECTIVE: Examine temporal alterations in vascular angiotensin II receptors (AT₁R and AT₂R) and determine vascular response to angiotensin II in growth-restricted offspring. STUDY DESIGN: Offspring of pregnant rats fed low-protein (6%) and control (20%) diet were compared. RESULTS: Prenatal protein restriction reprogrammed AT_1aR messenger RNA expression in male rats' mesenteric arteries to cause 1.7- and 2.3-fold increases at 3 and 6 months of age associated with arterial pressure increases of 10 and 33 mm Hg, respectively; however, in female rats, increased AT _1aR expression (2-fold) and arterial pressure (15 mm Hg) occurred only at 6 months. Prenatal protein restriction did not affect AT₂R expression. Losartan abolished hypertension, suggesting that AT_1aR plays a primary role in arterial pressure elevation. Vasoconstriction to angiotensin II was exaggerated in all protein-restricted offspring, with greater potency and efficacy in male rats. CONCLUSION: Prenatal protein restriction increased vascular AT₁R expression and vasoconstriction to angiotensin II, possibly contributing to programmed hypertension.