Effect of 5-Methylpyrazole-3-Carboxylic Acid (MPCA) on Fat Mobilization, Ketogenesis and Glucose Metabolism during Exercise in Man

Abstract

Prolonged leg exercise is accompanied by increased transport of free fatty acids (FFA) and glucose into the working muscles (I). When fat mobilization is prevented during exercise by prior injection of nicotinic acid, the ventilatory R.Q. rises and hypoglycemia was observed on one occasion (2). Ability to exercise at moderate work loads is not impaired, however, indicating that other substrates, presumably carbohydrate, can substitute for FFA as fuel under these conditions. In contrast, a subject with absent myophosphoryläse (McArdle’s syndrome), was unable to perform muscular work and to develop the characteristic ¹second wind’ when availability of FFA had been decreased by prior injection of nicotinic acid (3). This suggested that utilization of muscle glycogen might increase in healthy subjects who exercise after injection of nicotinic acid.

This work was supported by Public Health Service Grant HE-O6285.

Public Health Service International Fellow.