Amino acid concentrations in serum and urine after intravenous infusion of 1.5% glycine in prostatectomy patients.

Glycine 1.5% was given by intravenous infusion at a rate of 50 mg/min over 20 min to 10 patients (aged 57-79 years) scheduled for transurethral prostatectomy. The concentrations of amino acids in serum and urine were measured at 0, 10, 20, 50, 80, and 140 min in the experiments in order to study how elderly men handle a glycine load. The results show an increase in the serum concentrations of alanine, proline, glutamine, glycine, serine, and threonine. The apparent distribution volume for the excess glycine was 33 +/- 9 L, the half-life was 41 +/- 7 min, and the total body clearance was 0.56 +/- 0.08 L/min, while the renal clearance for glycine was 36 +/- 14 ml/min (mean +/- SD). There was an increase in the excretion of all amino acids that could be detected in the urine. The renal clearances of urea and creatinine was reduced in some of the patients. The absence of toxic symptoms is consistent with unchanged serum concentrations of ammonia and glutamate.