Cardiac glycogen in hypophysectomized rats subjected to fatty acid feeding

¹ Department of Biology, Bucknell University, Lewisburg, Pennsylvania

Three groups of rats were deprived of regular food for an 18-hour period. Twice during the 18 hours, stomach tube feeding was employed to administer oleic acid to one of the groups and glucose to another. The third group served as a nonfed control. A fourth group was fed. Earlier reports were verified that fasting of the hypophysectomized rat results in cardiac glycogen depletion. However, the animals fed oleic acid showed an elevation in heart glycogen which was above that of both the fed controls and glucose-fed animals. These results suggest that the mechanism of action by which growth hormone exerts its cardiac glycopexic effect in the intact animal may be one of increasing the quantity of fatty acids available, with a resultant sparing of glycogen in the heart. Unlike the heart, the rectus femoris did not accumulate glycogen in the animals fed fatty acid, but rather showed values correlated with those of the liver glycogen and blood glucose.