Fat compartments and apolipoprotein B-100 kinetics in overweight-obese men

Objective: To examine the association between the kinetics of very‐low‐density‐lipoprotein (VLDL)‐apolipoprotein B‐100 (apoB) and intraperitoneal, retroperitoneal, subcutaneous abdominal, and total adipose tissue masses (IPATM, RPATM, SAATM, and TATM, respectively) in overweight/obese men. Research Methods and Procedures: Hepatic secretion of VLDL was measured using an intravenous infusion of 1‐[13C]‐leucine in 51 men with a wide range of body mass index (25.1 to 42.2 kg/m2). Isotopic enrichment of VLDL‐apoB was measured using gas chromatography‐mass spectrometry and a multicompartmental model used to estimate VLDL‐apoB metabolic parameters. IPATM, RPATM, and SAATM (kilograms) were quantified between T11 and S1 using magnetic resonance imaging; TATM (kilograms) was determined using bioelectrical impedance. Insulin resistance was estimated by homeostasis model assessment (HOMA) score. Results: In stepwise regression, IPATM was the best predictor of hepatic secretion of VLDL‐apoB (r = 0.390, p < 0.005) and TATM was the best predictor of VLDL‐apoB fractional catabolic rate (r = 0.282, p < 0.05). IPATM remained significantly associated with VLDL‐apoB secretion after adjusting for TATM or HOMA score (r = 0.360, p < 0.01 and r = 0.310, p < 0.05, respectively). This association was also independent of age, dietary intake, and body mass index. None of the fat compartments were significantly associated with the fractional catabolic rate of VLDL‐apoB after adjusting for HOMA score. Discussion: In overweight/obese men, the quantity of both IPATM and TATM determine the kinetics of VLDL‐apoB. The effect of IPATM on VLDL‐apoB secretion is independent of both total fat mass and the degree of insulin resistance.