Dose-dependent half-life of glycine

The serum concentration of glycine was measured at hourly intervals after administration of between 10 and 91 g glycine to 17 patients undergoing transurethral resection of the prostate and of between 15 and 22 g glycine to 18 volunteers by intravenous infusion. The apparent half-life of glycine varied 10-fold (range 26-245 min) and increased in direct proportion to the amount of glycine given. This result can be explained by assuming a marked intracellular accumulation of a surplus of glycine. The dose-dependent half-life means that patients who absorb large amounts of irrigating fluid are exposed to excessive blood levels of glycine for a prolonged period of time.