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.
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