HYPOTHERMIA MARKERS - SERUM, URINE AND ADRENAL-GLAND CATECHOLAMINES IN HYPOTHERMIC RATS GIVEN ETHANOL

The effect of ethanol (2 g/kg) on body temperature and catecholamine ( CA) secretion in the cold (-20 degrees C) was investigated in adult ma le and female rats. The temperature dropped more rapidly in the female s, being similar to 10 degrees C after 3 h as compared with 18 degrees C in the males. Controls received the same dose of ethanol but were k ept at +20 degrees C. Increased concentrations of adrenaline (A) and n oradrenaline (NA) were already observed in the serum and urine of the females after 0.5 h of exposure, but at 1 h in the males. Serum values were low in the females after 2 and 3 h and urine values high in conn ection with the deep hypothermic state. The urine values of the males were also high at the end of exposure, when they, too, were hypothermi c. Depletion of amines was observed in the adrenals during the hypothe rmia phase, while CA concentrations tended to rise in the serum of the rats kept in the warm. The CA index (A:NA) was generally > 1 in both the serum and urine of the cold-exposed rats. The results show that fe male rats are less resistant to hypothermia than males, as indicated b y their more rapid drop in body temperature and exhaustion of CA secre tion. It is also apparent that urine CAs are worth measuring in cases of accidental hypothermia and possibly also other types of stress. An elevated CA index (> 1) seems to be an additional marker of hypothermi a, showing a proportionally greater increase in the secretion of A tha n NA during cold stress.