Variability in postheparin hepatic lipase activity is associated with plasma adiponectin levels in African Americans

Background: African Americans commonly have normal high-density lipoprotein cholesterol (HDL-C) and low triglyceride levels despite having insulin resistance and obesity. The higher than expected HDL-C levels are usually attributed to low levels of hepatic triglyceride lipase (HTGL) activity. Factors that regulate HTGL in African Americans are not well delineated. Methods: In the current study, HTGL activity was examined in relation to indices of body fat (body mass index [BMI] and waist circumference [WC]), insulin resistance (fasting plasma insulin and homeostasis model assessment of insulin resistance [HOMA-IR] index), and adipokines (adiponectin and leptin). Sixty-three African Americans (33 men, 30 women; median age 31 years, range 20-50 years; median BMI 28.6 kg/m², range 19.7-54.7 kg/m²) had anthropometry and measurement of postheparin lipase activities (HTGL), plasma HDL-C, triglycerides, and plasma adiponectin. Results: HTGL correlated strongly with HDL-C (r = -.52, p < .0001) and adiponectin (r = -.49, p < .001). HTGL increased with BMI and WC (r = .297, p = .018 and r = .301, p = .016, respectively). Adiponectin correlated strongly with HDL-C (r = .50, p < .0001) and triglycerides (r = -.493, p < .001). From multiple regression models, 28% of HTGL variability among African Americans can be explained by adiponectin levels in combination with gender and 35% of HTGL is explained with HDL-C included in the model. Conclusion: The data suggest that adiponectin is a significant metabolic concomitant of HTGL activity in African Americans.