CHANGES IN ELECTROLYTES AND 17-OXOSTEROIDS IN THE RAT SUBJECTED TO COLD ENVIRONMENT

Abstract

SUMMARY: 1. Transiently high plasma sodium and low potassium levels have been recorded in rats exposed to severe cold (0° C) for periods of up to 48 hr. At the same time the whole blood haematocrit value was reduced. No such changes occurred in similarly exposed adrenalectomized rats. 2. The Na/K ratio of urine produced by rats during the first 12 hr of exposure was found to be abnormally low, i.e. suggestive of sodium retention with potassium loss. 3. A rapid increase in urinary 17-oxosteroid (17-KS) output was shown to occur in rats exposed to cold, but the level falls to subnormal levels within 36–48 hr and remains subnormal even though the cold stress continues to act. 4. These observations have been tentatively interpreted as evidence of early adrenal hyperactivity with release of hormones of the 'mineralocorticoid-type' during the acute stress caused by cold.