[Biologic aging. 24. Circadian rhythm of lipid metabolism parameters in relation to age]

The age dependence of hepatic fatty acid synthesis and of the activities of lipogenic enzymes of the liver and of adipose tissue of Wistar-rats was investigated over the 24 hours period. The data were analyzed according to the so-called "cosinor procedure" for detecting circadian rhythms and for objectively describing their parameters. In the age groups 3 and 18 months hepatic fatty acid synthesis and the lipogenic liver enzymes glucose-6-phosphate dehydrogenase, 6-phospho-gluconate dehydrogenase and malic enzyme show circadian rhythms with maximum values in the early dark period. In adipose tissue of old rats the enzyme activities are lowered and no significant circadian rhythms for glucose-6-phosphate dehydrogenase and malic enzyme are detectable.