ABSTRACT
In summer/autumn, lipid is stored in adipocytes and during hibernation in winter it is mobilized from adipocytes for oxidative energy since the marmots do not eat. The amount of lipid stored in adipocytes can be affected by the rates of triacylglycerol (TG) synthesis and breakdown. Several hibernators, including the marmot, are unique in that they do not eat during the winter hibernation period. The rate of TG breakdown can be changed both by the hormonal milieu of the adipocyte in vivo and intrinsic changes in the ability of the adipocyte to respond to hormones. In rats, basal lipolysis increases in spring/summer and decreases in fall/winter although the effects may be confounded by seasonal changes in voluntary food intake. It is well known that mammalian hibernators increase mass during the summer and autumn months in preparation for winter hibernation.
