CHARACTERISTICS OF THE MYOCARDIAL PM-FABP - EFFECT OF DIABETES-MELLITUS

Properties of the myocardial PM-FABP were studied in normal and STZ-di abetic rats. The fluorescent fatty acids trans-parinaric and cis-parin aric acids were used as analogs of straight-chain (saturated) and kink ed-chain (unsaturated) fatty acids respectively. Parinaric acid bindin g was sensitive to trypsin. Trans-parinaric acid binding was more sens itive to this protease than the binding of cis-parinaric acid. Based o n the difference in sensitivity of parinaric acid binding we believe t hat there are two separate binding sites associated with myocardial PM -FABP; one for unsaturated fats and the other for saturated fats. Diab etes enhanced both cis- and trans-parinaric acid binding capacity in c ardiomyocytes; cis-parinaric acid by 2 fold and trans-parinaric acid b y 2.6 fold. In addition, there was a concomitant accumulation of free fatty acids and triglycerides in the hearts of the diabetic animals. T here was a 2.2 fold increase for fatty acids and a 1.6 fold increase f or triglycerides. This association between myocardial fatty acid build -up and enhanced myocardial PM-FABP during diabetes suggest that this carrier protein might have contributed to lipid accumulation in the he arts of the diabetic rats.