Mitochondrial membrane fatty acids of liver and heart of the euthermic and hibernating ground squirrel ( Citellus tridecemlineatus)

The fatty acid composition of liver and heart mitochondria of young and adult euthermic and hibernating ground squirrels Citellus tridecemlineatus were determined by gas chromatography. The liver mitochondria of young (first time in hibernation) have more palmitate and less stearic and linoleic than their euthermic controls. Arachidonic acid was absent in the control and hibernator and eicosapentaenoic and docosahexenoic acids were also absent only in the hibernators. The adult squirrels differed from young squirrels by the presence of arachadonic acid in the adult euthermic animals and its decline in the adult hibernator. A second major difference was the absence of eicosapentaenoic and docosahexenoic acids in the adult control and hibernator. The heart mitochondrial fatty acids, palmitic, stearic and oleic increased and linoleic acid decreased in the young hibernator. The unsaturation and polyunsaturation indexes fell and the monounsaturated index increased compared to the euthermic controls. The adult hibernator showed no significant changes in heart mitochondrial fatty acids when compared to the euthermic controls.