Effects of glucose on palmitate esterification by isolated rat diaphragms

¹ Department of Physiology, University of Michigan, Ann Arbor, Michigan

The uptake of palmitate -1-C¹⁴ and its conversion to various products by hemidiaphragm preparations incubated for 2 hours was measured in the presence and absence of added glucose or insulin. Following glucose and insulin addition, oxidation of palmitate to CO₂ by muscle obtained from either fed or starved rats was decreased, and incorporation of palmitate into neutral lipids freed of unesterified fatty acids was enhanced. The data indicate that the glucose sparing action on fatty acid oxidation by isolated muscle is related to stimulation of glyceride synthesis. Insulin alone was without effect on palmitate metabolism, but insulin addition in the presence of glucose accentuated the glucose sparing action. The data are discussed in relation to the overall effects of glucose on lipid metabolism in vivo, and possible sites of action of glucose on the stimulation of net glyceride synthesis are considered.