Fat distribution and adipose tissue metabolism in non-obese male black African and Caucasian subjects.

Twenty-four male black African (25.5 +/- 3.0, mean +/- s.d., years of age) and 24 male Caucasian (21.5 +/- 3.6) subjects, ascertained as sedentary individuals, participated in this study designed to determine whether there were racial differences in fat distribution and adipose tissue metabolism while controlling the differences in body fat. An adipose tissue biopsy was obtained from the suprailiac region for the determination of basal (BL), epinephrine submaximal 10(-4) M (ESML) and maximal 10(-3) M (EML) stimulated lipolysis, basal (BLG) and maximal insulin 9 microU/ml (ILG) stimulated lipogenesis and heparin releasable lipoprotein lipase (LPL) activity. Body density was determined through underwater weighing procedures and body fat derived with the Siri equation. The following skinfolds were also measured: triceps, biceps, subscapular, abdomen, suprailiac, front thigh and medial calf. Caucasians were matched with the black Africans for age, body weight and body density. Results indicated that when Caucasians and black Africans of similar percentage body fat were compared, no significant differences were observed in the total amount of subcutaneous fat, fat distribution and suprailiac mean fat cell size. Moreover, no significant differences were observed between the two groups for BL, BLG, and ILG of adipose tissue. However, black Africans had higher (P less than 0.01) epinephrine stimulated lipolytic values (ESML and EML) and LPL activity (P less than 0.01) than the Caucasian subjects. These results suggest that for a comparable level of fatness and similar fat morphology and distribution, there are racial differences in adipose tissue metabolism.