Hypothalamic catecholamines and tolerance for severe cold in ethanol-treated guinea-pigs.

1 The effect of ethanol (2g/kg) on hypothalamic catecholamines in guinea-pigs kept at room temperature (20 degrees C) and in severe cold (-20 degrees C) for 1.5 h was determined. Serum glucose, triacyl-glycerols and free fatty acids (FFAs), glycogen in liver and skeletal muscle and total lipid and triacyglycerols in the interscapular adipose tissue were also determined. 2 Ethanol increase the noradrenaline and adrenaline content of the hypothalamus at 20 degrees C and reduced ther rectal temperature by about 2 degrees C. The hypothalamic noradrenaline content of the ethanol-treated guinea-pigs exposed to cold, in which the fall in rectal temperature was about 8 degrees C, was higher than in the controls, whose rectal temperature decreased only by about 2 degrees C. 3 Cold exposure increased FFA concentration in serum and reduced skeletal muscle glycogen and serum glucose concentrations in both groups, but no significant differences were found in the carbohydrate and lipid values between the groups at -20 degrees C. 4 It is possible that the diminished cold tolerance in the ethanol-treated guinea-pigs might be due, at least in part, to the effect of ethanol on the catecholamines in the hypothalamus.