Inhibition of endogenous lactate turnover with lactate infusion in humans

The extent to which lactate infusion may inhibit endogenous lactate production, though previously considered, has never been critically assessed. To examine this proposition, single injection tracer methodology (U-14C Lactate) has been used for the estimation of lactate kinetics in 12 human subjects under basal conditions and with the infusion of sodium lactate. The basal rate of lactate turnover was measured on a day before the study with lactate infusion, and averaged 63.7 + 5.5 mg/kg/h. Six of these individuals received a stable lactate infusion at an approximate rate of 160 mg/kg/h, while the remaining six individuals were infused at the approximate rate of 100 mg/kg/h. It has been found that stable lactate infused at rates approximating 160 mg/kg/h consistently produced a complete inhibition of endogenous lactate production. Infusion of lactate at 100 mg/kg/h caused a lesser and more variable inhibition of endogenous lactate production (12% to 64%). In conclusion, lactate infusion significantly inhibits endogenous lactate production.