The aim of the present study was to investigate whether there are race differences in the regulation of lipolysis in abdominal and gluteal adipocytes of postmenopausal African-American (AA) and Caucasian (C) women. Higher rates of insulin-suppressed lipolysis, as measured by glycerol or fatty acid release in abdominal subcutaneous adipocytes, in overweight postmenopausal AA compared to C women were observed even after adjustment for percent fat and intra-abdominal (visceral) fat area. The higher rates of lipolysis in adipocytes of AA were also strongly associated with their hyperinsulinemia. Basal [submaximal phenylisopropyl adenosine (PIA)-suppressed] lipolysis was also found to be ~30% higher on a per cell basis in the larger adipocytes of the AA women. Thus, these data suggest that the decreased responsiveness of abdominal adipocytes to antilipolytic effectors may contribute to higher fatty acid availability and consequently to racial differences in insulin resistance.
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