Changes in adipose tissue hormone-sensitive lipase activity and cAMP during ethanol withdrawal

The time course of the effects of ethanol withdrawal on brown and white adipose tissue hormone-sensitive lipase, cAMP production, and phosphodiesterase have been investigated after chronic drinking or liquid diet schedules. Chronic drinking significantly reduced brown adipose tissue hormone-sensitive lipase activity and cAMP levels from control. During withdrawal, there was a rebound increase to 200% control, peaking 9 h into withdrawal. White adipose tissue hormone-sensitive lipase activity and cAMP accumulation were significantly raised by both treatment schedules. Ethanol liquid diet produced a significant fall in adipose tissue hormone-sensitive lipase activity and cAMP accumulation. In brown fat, there was a rebound increase in hormone-sensitive lipase activity and cAMP; in white fat, no rebound was observed. In brown fat, the reductions in hormone-sensitive lipase activity and cAMP accumulation after chronic drinking coincided with an increase in phosphodiesterase activity. In white fat, the rise in cAMP and hormone-sensitive lipase activation coincided with a decrease in phosphodiesterase activity. We conclude that the effects of chronic ethanol on hormone-sensitive lipase activity are cAMP-dependent and mediated via alterations in phosphodiesterase activity.