Increased Gluconeogenesis Is Not an Early Feature of Whole-Body Insulin Resistance in Black Women—The Federal Women Study

In contrast to white women, fasting hyperglycemia is not an early diabetes risk marker in black women. The etiology of this racial difference in risk is unknown but could be related to differences in rates of gluconeogenesis and hepatic fat in black women. Using stable isotope tracers [2H2O], [6,62H2]glucose, and ([2H5]glycerol), we partitioned basal glucose production into its two components (gluconeogenesis and glycogenolysis) and measured basal whole body lipolysis. Whole body (SI), hepatic (HIS) and adipose tissue insulin sensitivity were calculated in two groups of federally employed pre-menopausal women, without diabetes: 24 black and 19 white; age 37±6 (mean±SD), range 25-50y; BMI 33±6, range 24.9-45.2 kg/m2. Hepatic and visceral fat were measured by proton MRS. The prevalence of prediabetes (17% vs. 26%), age and BMI were similar in blacks and whites, all P>0.4). Black women had less fasting hyperglycemia (4% vs. 22%, P=0.1), lower visceral and hepatic fat (P0.5). Basal glucose, insulin and FFA concentrations were similar in both groups (P>0.05). Blacks had lower glucose production (2.52±0.34 vs. 2.75±0.28 mg·kglbm-1·min-1, P