In this study, we examined whether
weight loss-induced changes in plasma
organochlorine compounds (OC) were associated with those in skeletal muscle markers of glycolytic and oxidative metabolism. Vastus lateralis skeletal muscle
enzyme activities and plasma OC (
Aroclor 1260,
polychlorinated biphenyl 153,
p,p'-DDE,
beta-hexachlorocyclohexane, and
hexachlorobenzene) were measured before and after a weight loss program in 17 men and 20 women. Both sexes showed a similar reduction in
body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (P < 0.05). Enzymatic markers of glycolysis,
phosphofructokinase (PFK) activity, and oxidative metabolism, beta-hydroxyacyl-
CoA dehydrogenase (HADH),
citrate synthase (CS), and
cytochrome c oxidase (COX) activities, remained unchanged after
weight loss. A significant increase in plasma OC levels was observed in response to
weight loss, an effect that was more pronounced in men. No relationship was observed between changes in OC and those in PFK activity in either sex [-0.31 < r < 0.12, not significant (NS)]. However, the greater the increase in plasma OC levels, the greater the reduction in oxidative
enzyme (HADH, CS, COX) activities was in response to
weight loss in men (-0.75 < r < -0.50, P < 0.05) but not in women (-0.33 < r < 0.33, NS). These results suggest that the
weight loss-induced increase in plasma
pollutant levels is likely to be associated with reduced skeletal muscle oxidative metabolism in men but not in women.