Lipid peroxidation and lipolysis during fasting.

The present work was aimed at investigation of lipid peroxidation during fasting and its effects upon metabolism of adipose tissue, especially lipolytic activity. An increase in the lipid peroxidation was demonstrated in an animal model (male rats) through accumulation of lipofuscin-like pigments (LFP), the end product of lipid peroxidation. The increased LFP levels correlated with a decrease in the activity of hormone-sensitive lipase. LFP content increased in the plasma, liver and adipose tissue. The time-course of the changes depended on the initial body mass of the animals. Correlations were found between lipolytic activity and LFP content in adipose tissue and in plasma. In the course of the repeated cycles of fasting--feeding, the changes of LFP and lipolysis were antiparallel to each other. During four cycles, there was a net increase in LFP and a net decrease in lipolysis. The lipolytic activity depended on many factors, among which we identified the initial body mass of animals, their age, and the way of feeding. The results obtained in this animal model enable application of the methods used in the investigation of fasting in obese patients.