STEADY STATE OXIDATION OF GLUCOSE IN THE HYPOTHYROID DIABETIC RAT: A ROLE FOR THE ADRENAL CORTEX IN GLUCOSE OXIDATION

Abstract

A steady state between the specific activities of blood glucose and expired CO2in the hypothyroid diabetic rat was maintained for extended periods of time following a single intraperitoneal injection of glucose-1-C14or glucose-6-C14. Rates of oxidation of the labelled sugars were measured during the steady state.Glucose oxidation by way of glycolysis and the tricarboxylic acid cycle in the hypothyroid diabetic rat paralleled the decrease in expired CO2but glucose oxidation by way of the hexose monophosphate pathway was completely suppressed.It is suggested that the observed inhibitory effect on the hexose monophosphate pathway is due to the maintenance of diphosphopyridine nucleotide in the reduced form as the result of goitrogen inhibition of steroid-catalyzed transhydrogenation.The results suggest that steroid concentration may be a critical factor in regulation of glucose oxidation by way of the hexose monophosphate pathway.