Stimulation of myocardial lactate extraction by oxfenicine (L-hydroxyphenylglycine)

In animal experiments oxfenicine (L-hydroxyphenylglycine) (LHPG)has been shown to increase myocardial carbohydrate utilizationand decrease fat consumption. Seven patients, six of whom provedto have coronary artery disease, were studied during diagnosticcardiac catheterization. Myocardial substrate extraction, coronarysinus flow, cardiac output and left ventricular pressure weremeasured at basal heart rale and three pacing rates before andafter 800 mg oxfenicine (LHPG). A small decrease in systolicpressure at low heart rates and reduction of end-diastolic pressureat the highest pacing rate were the only haemodynamic changesobserved after the drug. Coronary sinus flow and myocardialoxygen uptake did not change, although there was a small fallin arterio-venous oxygen difference at basal heart rate. Afterthe drug lactale extraction ratio increased in all patientsat each heart rate. Pyruvate extraction ratio increased afteroxfenicine (LHPG) significantly at basal heart rate and thelowest pacing rate. Arterial free fatty acid concentration roseand extraction ratio fell. It is concluded that oxfenicine (LHPG)has a potent effect upon lactate metabolism and is without majorhaemodynamic effects.