The effect of Tris (hydroxymethyl) aminomethane on glucose utilization of skeletal muscle

Abstract

The effect of Tris (hydroxymethyl) aminomethane (THAM) on the glucose metabolism of the isolated rat diaphragm was studied in vitro. The addition of THAM (pH 7.45) to the incubation medium significantly stimulated the uptake of glucose, lactic acid production and the oxidation of glucose to CO 2, but significantly decreased the glycogen content of the tissues. The stimulatory effect of THAM on glycolysis was independent of the bicarbonate or CO 2 concentration in the medium. THAM-chloride (0.05 M) increased glycolysis significantly when added to the balanced salt solution or when substituted for equimolar concentrations of NaCl in the medium; however, the former effect was significantly greater. The effect of insulin and THAM on glucose uptake and lactic acid production was additive, while the effect of the 2 agents on glycogen synthesis was opposite. Insulin stimulated the membrane transport of d-xylose into the intact rat diaphragm preparation, while THAM had no effect. THAM did not affect the incorporation of C 14 from leucine into proteins. It is suggested that THAM stimulates the utilization of glucose by skeletal muscle directly, by a mechanism which is different from that of insulin, but insulin has a permissive role. These findings could explain the hypoglycemia observed in human subjects and animals following the infusion of THAM.