ABSTRACT
During the summer feeding period, mammalian hibernators may increase their body mass by 100%, primarily by storing huge amounts of triacylglycerol (TG) in white adipose tissue. These TG stores are depleted during hibernation. A deficiency of essential fatty acids (FA) adversely affects the marmots' ability to survive through winter. The preference of monoacylglycerol acyltransferase (MGAT) activity for specific 2-monoacylglycerol could lead to greater retention of selected essential FA in different tissues. MGAT activity is consistently expressed at high activity in animals undergoing high rates of lipolysis. Lipid metabolism plays a major role in hibernators, but few studies have examined the critical enzymes of FA and TG synthesis in hibernators and none have measured these enzymes seasonally in the major organs of lipid homeostasis. Like hibernators, many animals undergo physiological periods that are characterized by high rates of TG hydrolysis and ß-oxidation.
