Effect of the fatty acid oxidation inhibitor 2-tetradecylglycidic acid on pyruvate dehydrogenase complex activity in starved and alloxan-diabetic rats.

Intravenous administration of the fatty acid oxidation inhibitor 2-tetradecylglycidic acid had no effect on the proportion of pyruvate dehydrogenase complex in the active form in heart, diaphragm or gastrocnemius muscles or in liver, kidney or adipose tissue of fed normal rats. The compound reversed the effect of 48h starvation (which decreased the proportion of active complex) in heart muscle, partially reversed the effect of starvation in kidney, but had no effect in the other tissues listed. The compound failed to reverse the effect of alloxan-diabetes (which decreased the proportion of active complex) in any of these tissues. In perfused hearts of fed normal rats, 2-tetradecylglycidate reversed effects of palmitate (which decreased the proportion of active complex), but it had no effect in the absence of palmitate. In perfused hearts of 48h-starved rats the compound increased the proportion of active complex to that found in fed normal rats in the presence or absence of insulin. In perfused hearts of diabetic rats the compound normalized the proportion of active complex in the presence of insulin, but not in its absence. Palmitate reversed the effects of 2-tetradecylglycidate in perfused hearts of starved or diabetic rats. Evidence is given that 2-tetradecylglycidate only reverses effects of starvation and alloxan-diabetes on the proportion of active complex in heart muscle under conditions in which it inhibits fatty acid oxidation. It is concluded that effects of starvation and alloxan-diabetes on the proportion of active complex in heart muscle are dependent on fatty acid oxidation. Insulin had no effect on the proportion of active complex in hearts or diaphragms of fed or starved rats in vitro. In perfused hearts of alloxan-diabetic rats, insulin induced a modest increase in the proportion of active complex in the presence of albumin, but not in its absence.