ALTERATIONS OF LIPOLYSIS AND LIPOPROTEIN-LIPASE IN CHRONICALLY NICOTINE-TREATED RATS

These studies examined the cellular mechanisms for lower adiposity see n with nicotine ingestion. Rats were infused with nicotine or saline f or 1 wk and adipocytes isolated from epididymal fat pads. Nicotine-inf used rats gained 37% less weight and had 21% smaller fat pads. Basal l ipolysis was 78% higher whereas the maximal lipolytic response to isop roterenol was blunted in adipocytes from nicotine-infused rats. The an tilipolytic actions of adenosine and the levels of serum catecholamine s were unaffected by nicotine. The nicotine-induced alteration in lipo lysis was not associated with any changes in hormone-sensitive lipase. Nicotine caused a 30% decrease in lipoprotein lipase (LPL) activity, without any changes in LPL mass or mRNA levels, in epididymal fat in t he fed state. In contrast, LPL activity, mass, and mRNA levels in hear t were increased by nicotine whether animals were fed or fasted. These studies provide evidence for multiple mechanistic events underlying n icotine-induced alterations in weight and suggest that nicotine divert s fat storage away from adipose tissue and toward utilization by muscl e.