Inhibition of mitochondrial carnitine acylcarnitine translocase-mediated uptake of carnitine by 2-(3-methyl-cinnamyl-hydrazono)-propionate. Hydrazonopropionic acids, a new class of hypoglycaemic substances, VI

The rate of mitochondrial carnitine-carnitine exchange mediated by carnitine acylcarnitine translocase was measured by following the uptake of L-[methyl-14C]carnitine. It was demonstrated that the hypoglycaemic compound 2-(3-methyl-cinnamyl-hydrazono)-propionate causes a concentration-dependent decrease in the rate of the translocase-mediated transport of carnitine in guinea pig liver mitochondria. Apparent initial influx rates were decreased by 20% at 0.3 mmol/1 2-(3-methyl-cinnamyl-hydrazono)-propionate, 38% at 0.5 mmol/l, and 75% at 2.0 mmol/l of this compound. This finding may explain the previously observed inhibitory effects of this substance on long-chain fatty acid oxidation, ketone body production and gluconeogenesis.