No abstract

When the hamster is exposed to cold (6 ± 1 C), there is a profound block in hepatic lipogenesis from C14-acetate within 48 hr. By 8 weeks of cold exposure this block has been repaired to 74% of the control value. During hibernation, which generally occurs after the 8th week, a block in lipogenesis is again present. By 6 hr of arousal, the degree of lipogenesis has been either slightly repaired or has returned almost to the 8-week level. Accompanying this block in lipogenesis is an increase in the production of C14O2 from C14-acetate in animals exposed to cold. In vitro addition of .02 m glucose did not stimulate lipogenesis in hepatic tissue of cold-exposed hamsters, except for a few of those animals aroused from hibernation for 6 hr. Addition of .02 m succinate in vitro did not increase lipogenesis or C14O2 production from C14-acetate. Fructose repaired the hepatic lipogenesis in all groups of cold-exposed hamsters. It was concluded that the cold-exposed and hibernating hamster has biochemical lesions involving the glucokinase reaction and some other step in the glycolytic pathways of the liver.

Incorporation of C14 from acetate-1-C14 into lipid and CO2 by epididymal fat from golden hamsters kept at room temperature, acclimated to 5 ± 1 C, in hibernation and arousing from hibernation, was measured in vitro at 37 C. Summer and winter series were compared. The C14O2 production by tissue from control and acclimated animals was similar but the C14O2 production of tissue from hibernating and arousing hamsters was significantly greater than that from acclimated animals. There was a large increase in the lipid-C14 of tissue from cold-acclimated animals and this increase persisted into hibernation but was slightly depressed in tissue from arousing animals. Many acclimated and all hibernating hamsters had involuted testes and a greater incorporation of C14 into lipid than those with noninvoluted testes. A greater percentage of hamsters hibernated in the cold room during the winter and at this time the incorporation of C14 into lipid by the fat pad was greater than in the summer.

No abstract

No abstract