THE EFFECT OF ACUTE AND CHRONIC COLD EXPOSURE ON TISSUE LIPIDS IN THE RAT

Abstract

The liver and gastrocnemius muscles from rats undergoing acute and chronic cold exposure to 5 °C were totally excised after an in situ perfusion with isotonic saline. Total lipid was extracted from the tissue and the lipid classes separated by countercurrent distribution.There was no difference between the groups in the amount of phospholipid present in either liver or muscle. However, the neutral lipids of both tissues were decreased in the acclimated group. Though acute exposure caused a decrease in the neutral lipid levels of muscle, the liver levels remained unchanged. Only the free fatty acid levels in liver were affected by acute exposure, and these increased.The decrease in neutral lipid of muscle in the acutely exposed group suggests that there is an immediately available source of lipid in muscle in response to the stress of cold exposure.