α-Oxoglutarate Carboxylation in Liver Mitochondria from Normal,Alloxan Diabetic and Streptozotocin Diabetic Rats

Abstract

Summary

Rat liver mitochondria, incubated in media containing 4 mM ATP, 10 mM MgCl₂, 6.7 mM P_i 13.3 mM TEA, 6.7 mM α-oxoglutarate, and 20 mM HCO₃ ^-, oxidized α-oxoglutarate through the tricarboxylic acid cycle and utilized a portion of the reducing equivalents produced by this oxidation to drive α-oxoglutarate to citrate via reductive carboxylation. Streptozotocin and alloxan diabetes increased the rates of oxidation and citrate accumulation. L-Octanoylcarnitine inhibited both α-oxoglutarate oxidation and carboxylation. Insulin, glucagon, and dibutyryl cyclic AMP, added in vitro, did not affect α-oxoglutarate oxidation or carboxylation.