Increase in plasma pollutant levels in response to weight loss in humans is related to in vitro subcutaneous adipocyte basal lipolysis

OBJECTIVE: To examine whether weight loss-induced changes in in vitro basal lipolysis of subcutaneous abdominal and femoral fat cells were related to those in plasma organochlorine levels. DESIGN: A 15 week weight loss program induced by a moderate caloric restriction. SUBJECTS: Seventeen men and 20 women (age 36 - 50 y, body fat 25 - 50%). MEASUREMENTS: In vitro basal lipolysis of subcutaneous abdominal and femoral adipocytes and plasma levels of five polychlorinated biphenyl congeners (Aroclor 1260, PCBs 118, 138, 153 and 180) and three chlorinated pesticides (dichlorodiphenyl dichloroethene (p,p'-DDE), beta-hexachlorocyclohexane (beta -HCH) and hexachlorobenzene (HCB)) were measured before and after the weight reducing program. RESULTS: Both genders showed a similar reduction in body weight (similar to 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean +/- s.d., 9.4 +/- 4.1 vs 5.9 +/- 5 kg, respectively, P < 0.05). Mean basal fat cell lipolysis did not vary before and after weight reduction, regardless of depots and genders. In response to weight loss, significant increases of all organochlorines investigated were observed in men, whereas only p,p'-DDE, Aroclor 1260, PCBs 153 and 180 significantly rose in women. In men, higher the increase in basal lipolysis of subcutaneous abdominal or femoral adipocytes, greater the rise in plasma levels of most pollutants (HCB, Aroclor 1260, PCBs 118, 138 and 153) was in response to weight loss (0.51 < r < 0.70, P < 0.05). Similar positive correlations were also observed in women but only a few reached statistical significance (p,p'-DDE, PCBs 118 and 180). CONCLUSION: The weight loss-induced increase in plasma pollutant levels is related to the rise in subcutaneous abdominal and femoral adipocyte basal lipolysis, especially in men.