Effects of glucose on fatty acid oxidation by diaphragms from normal and alloxan-diabetic fed and starved rats

Abstract

Palmitic acid-1-C¹⁴ oxidation by hemidiaphragms was measured in tissues from fed and starved normal and alloxanized rats. Muscle from normal rats starved for 3 days or longer showed an enhanced conversion of added palmitate to C¹⁴O₂, while fasting for 1 or 2 days had little effect on fatty acid degradation by diaphragms from normal rats. Tissues from fed or starved alloxan diabetic animals had an augmented oxidation of labeled palmitate. The addition of glucose to the medium spared fatty acid oxidation by diaphragms from starved or diabetic rats but did not influence palmitate degradation by tissues from normal fed rats. The presence of insulin increased the glucose sparing action on long-chain fatty acid oxidation but was without effect on palmitate oxidation in the absence of added glucose. The conversion of C¹⁴-octanoic acid to C¹⁴O₂ by muscle was not influenced by previous starvation nor by addition of glucose to the medium. Glucose-U-C¹⁴ and glucose-1-C¹⁴ conversion to C¹⁴O₂ and glycogen were essentially the same in diaphragms from fed and starved animals.