Research Project
2519399
Hyperinsulinemia and insulin resistance are strongly linked with essential hypertension (EH) and non-insulin dependent diabetes mellitus (NIDDM), both of which afflict African American women with greater incidence, morbidity, and mortality compared to Caucasians. The insulin resistance syndrome is often characterized by upper body obesity. In women, this body morphology is related to higher levels of androgens. In young adult African Americans we have detected significant gender differences in both hyperinsulinemia and insulin resistance, with African American women exhibiting higher plasma insulin and greater insulin resistance compared to men. In this proposal we will distinguish whether the observed gender differences in plasma insulin and insulin resistance reflect biologic differences, or whether the gender differences in insulinemia are determined by greater adiposity in women. We will also determine if the hyperinsulinemia per se contributes to excess risk for cardiovascular disease in African American women. Since higher androgenicity is linked with cardiovascular risk in women we will determine if the risk factors associated with hyperinsulinemia are modulated by sex hormones. The study is designed to test the overall hypothesis: Cosegregation of hyperinsulinemia and androgenicity will correlate with greater cardiovascular risk in African American women. Women who have hyperinsulinemia and higher androgen levels will have high blood pressure, impaired glucose tolerance, and altered serum lipids, compared to women who do not have both phenotypes. The study will be conducted on a population of young adult African American men and women that we have investigated longitudinally. We will also study the mothers of the young women. We will 1) obtain anthropometric and blood pressure measures, 2) quantitate glucose tolerance by glucose tolerance test, and insulin sensitivity by insulin clamp, 3) measure serum lipids, and 3) assess androgen levels using assays of plasma sex-hormone binding globulin and free testosterone. Results of these studies will determine if insulin and androgens define risk for cardiovascular disease in African American women. These data can lead to new insights to the excess prevalence of EH and NIDDM in African American women, and to the development of strategies for prevention.
