Adipocyte lipolysis, hormonal and metabolic changes in ethanol-drinking rats

The effect of ethanol drinking on some hormonal and metabolic changes in the rat and on lipolysis in isolated adipocytes was tested. Male growing Wistar rats divided into two groups were used in the experiment. Ten percent ethanol solution as the only drinking fluid for 2 weeks depressed body weight gain. The diminution of blood insulin with simultaneous increase in leptin concentration found in these rats suggest that the physiological regulation of leptin secretion is disturbed by ethanol. Liver triglycerides content was substantially augmented due to ethanol ingestion. Adipocytes were isolated from both groups of rats by collagenase digestion and the lipolytic activity of these cells was compared. Isolated cells (10(6)/ml) were incubated for 90 min in Krebs-Ringer buffer (pH 7.4, 37 degrees C) containing 3 mm glucose and different lipolytic modulators: adrenaline (1 microm), insulin (1 nm), dibutyryl-cAMP (1 mm) and DPCPX (a selective antagonist of adenosine A1 receptor, 1 microM). To determine basal lipolysis cells were incubated without lipolytic agents. Lipolysis was determined by the amount of glycerol released from cells to the incubation medium. Basal and adrenaline-induced lipolysis was depressed in adipocytes of ethanol-drinking rats. The antilipolytic activity of insulin was the same in both groups of isolated cells. Lipolysis induced by dibutyryl-cAMP was only slightly reduced due to ethanol consumption, whereas triglycerides breakdown evoked by adenosine A1 receptor antagonism was unchanged. Results obtained in vitro indicate that subchronic ethanol drinking attenuates basal and stimulated lipolysis in adipocytes, however, the antilipolytic effect of insulin and the adenosine pathway are unchanged.