The rate of mitoehondrial carnitine-carnitine exchange mediated by carnitine acylcarnitine translocase was measured by föllowing the uptake of L-[methyl-14 C]carnitine. It was demonstrated that the hypoglycaemic compound 2-(3^methyKcinnamyl-hydrazono)-propionate causes a concentration-dependent decrease in the rate of the translocase-mediated transport of carnitine in guinea pig liver mitochondria. Apparent initial infhix rates were decreased by 20% at 0.3 mmol/1 2-(3-methyl-cinnamyl-hydrazono)-propionate, 38% at 0.5 mmol/1, and 75% at 2.0 mmol/1 of this compound. This finding may explain the previously observed inhibitory effects öf this substance on long^chain fatty acid oxidation, ketone body production and gluconeogenesis.
™ "Among these hydrazpnes, 2-(3^methyl-cinnamyl-hyHydrazpnes of pyruvate exert a powerful hyppgly-drazpnp)-propionate is a powerful hypoglycaemic agcaemic effect in varioüs labprätpry aiiimals (1-6). ent, the metabolic effects of which have already been In addition to theif potential usefulness for the treat-studied in considerable detail. Studies on the mode ment of diabetes, such substances facilitate studies of action revealed that 2-(3-methyl-cinnamyl-hydraon the interrelationship betwen metabolic pathways, zpno)-prppionate inhibits gluconeogenesis in guinea provided that their mode of action is known. pig liver (7,8). Furthermore in the rat and in the guinea pig an increase in the concentration of free .fatty acids in the plasma and a decrease in blood 0 Preliminary results of this study were presented at the third ketone body concentration was observed, which meetingoftbeGermanAsspciation for the Studyof the Liver pointed to an Inhibition of long-chain fatty acid oxm Hannover 1987 (abstract: Z. Gastroenterologie (1987) 25. idation (5)e It has been suggested that this Inhibition 2 ) For previous publications see I.e. (3-5), (8), (25). by 2-(3-methyl-cinnamyl-hydrazono)-propionate oc-