Fatty Acids of the Liver and the Blood Plasma During the Hibernation of the Yakutian Ground Squirrel Spermophilus undulatus

Abstract

Abstract—We investigated the effect of hibernation on the levels of fatty acids and monoglycerides in the liver tissue and in the blood plasma of the Yakut ground squirrel Spermophilus undulatus. In the liver tissue of dormant animals (the hibernation bout) the level of fatty acids (μg of fatty acids/mg of protein) increases by 5 times compared to the summer period. In ground squirrels that are active in the winter (a hibernation interbout), the level of fatty acids was halved compared to dormant ones. The level of monoglycerides in the liver of hibernating animals was halved compared to summer animals. The protein level (mg/g of tissue) in the liver did not change during hibernation. The level of fatty acids decreased by half in the blood plasma of animals during the hibernation and returned to summer level in active winter animals. The level of monoglycerides in the blood plasma did not change. The protein concentration in the blood plasma during hibernation is increased by 20% compared with the summer period. Changes in the level of fatty acids in the liver and blood plasma indicate the adaptive role of fatty acids in the hibernation of the ground squirrel S. undulatus. A high fat level is maintained in the liver of hibernating animals with a reduced level of fatty acid in the blood plasma during torpor. Fatty acids of the liver play a role in the return of the fatty acid plasma level to the summer level during the hibernation interbout. The analysis of our results demonstrated that the liver plays a role in the regulation of plasma lipids, acting as a depot for fatty acids with an adaptive decrease in their concentration in the blood plasma during the hibernation season. A high level of liver fatty acids can cause adaptive changes in the lipid composition of the intracellular organelles of the liver tissue during the hibernation of the ground squirrel S. undulatus.