Fasting serum free glycerol concentration is a potential surrogate marker of visceral obesity and insulin sensitivity in middle-aged Japanese men

Abstract Background Triglyceride (TG) is a tri-ester composed of a glycerol and three fatty acids. Degradation of TG in adipose tissue is increased in the fasting state, but inhibited in the postprandial state. Although insulin suppresses adipose TG degradation, patients with insulin resistance have high concentrations of insulin and free glycerol (FG) in the fasting state. Objective We examined whether the fasting FG concentration reflects visceral obesity and insulin sensitivity in middle-aged Japanese men. Methods We measured the fasting serum FG concentration in 72 males aged 30–50 years using a simple enzymatic method. The subjects were divided into tertiles according to their homeostasis model assessment of insulin resistance (HOMA-IR). Besides routine glucose- and lipid-related parameters, we determined insulin sensitivity as the rate of glucose disappearance in a two-step hyperinsulinemic euglycemic clamp, and the abdominal visceral fat area (VFA) by magnetic resonance imaging. Results The highest HOMA-IR tertile group had a higher fasting FG concentration than the lowest- and middle-tertile groups (0.077 ± 0.024 vs. 0.063 ± 0.017 and 0.061 ± 0.016 mmol/L, P Conclusion The fasting FG concentration reflects VFA and insulin sensitivity in middle-aged Japanese men. The fasting FG concentration may be a potential surrogate marker of visceral obesity and insulin resistance in outpatients.