Abstract P638: Muscadine Grape Seed Extract Improves Glucose Handling in Female but not Male Hypertensive (mRen2)27 Rats

Abstract

Muscadine grapes ( Vitis rotundifolia ) are enriched in polyphenols and other flavan-3-ols that may potentially convey cardiovascular benefit through the antioxidant properties of these compounds. In the current study, we established the effects of a muscadine grape extract (MGE, Piedmont Research and Development Corp.) on blood pressure and metabolic function in 20 week-old female and male hemizygous (mRen2)27 transgenic rats, an Ang II-AT 1 R-dependent model of hypertension. Littermates were treated with MGE (0.2 mg/mL) in the drinking water for 6 weeks (n = 7; male and n=5; female); controls were given water only (n = 7; male and n = 6; female). Intraperitoneal glucose tolerance test (IPGTT) assessed glucose metabolism and serum levels of glucose and insulin were also determined. There were no significant differences between the control and MGE-treated groups for either sex in systolic blood pressure (males: 168 ± 5 vs. 179 ± 4 mmHg; females: 183 ± 5 vs. 162 ± 11 mmHg) or body weight (males: 513 ± 12 vs. 508 ± 22 g; females: 297 ± 4 vs. 294 ± 89 g). The glucose response (area under the curve - AUC) in the female MGE-treated group was markedly lower compared to the untreated controls; however, MGE elicited no effect on the glucose AUC in males (see figure). Although MGE did not influence serum insulin AUC in males or females, the MGE-treated females exhibited a trend for a lower glucose-insulin index. We conclude that MGE intake improves glucose utilization in adult female hypertensive rats independent of changes in blood pressure or body weight. The mechanism(s) underlying the differential response to MGE between the female and male (mRen2)27 transgenic remain to be established