Alternative pathways of carbohydrate metabolism in foetal and adult tissues

Abstract

Tissue slices were incubated with [1-C14]-glucose and [6-C14]glucose to evaluate the relative rates of glycolysis and the hexose monophosphate oxidative pathway in a variety of fetal and adult tissues. The effects of anerobiosis and of the addition of unlabelled pyruvate, D-2-deoxyglucose, ascorbate, and di- and tri-phosphopyridine nucleotide were tested. There was no significant change in the relative rates of metabolism via these 2 alternative pathways of carbohydrate metabolism in any of the tissues over the period of fetal development from 8 to 25 weeks'' gestational age. The activity of the hexose monophosphate pathway in different tissues ranged from the fetal cerebral cortex; in which it is essentially zero, to the adrenal cortex, in which it accounts for most of the glucose metabolized. Comparative studies, however, revealed wide differences in the relative activities of the 2 pathways in comparable tissues of different species.