Infusion of glycine does not attenuate in vivo ischemic acute renal failure in the rat

Abstract

Recent in vitro studies have demonstrated that the amino acid glycine affords profound protection against hypoxic injury in isolated rat proximal tubules and the isolated perfused rat kidney. In the present study we have examined the in vivo effect of glycine in a rat model of ischemic acute renal failure. Acute renal failure was induced in rats by right uninephrectomy and clamping of the left renal artery for 45 or 60 minutes. Glycine infusion was initiated 60 minutes before renal artery clamping at a rate to increase serum glycine levels above 2.0 mmol/L. Control rats received a 5% dextrose infusion. In the control rats, both 45 minutes and 60 minutes of clamping resulted in reversible acute renal failure and a serum creatinine level after 24 hours averaging 2.1 +/- 0.3 mg/dl (mean +/- SEM) and 3.3 +/- 0.4 mg/dl, respectively. Glycine treatment did not attenuate the decrease of renal function in the 45-minute and 60-minute models, with serum creatinine averaging 2.1 +/- 0.4 mg/dl and 3.4 +/- 0.5 mg/dl, respectively. Histologic examination also did not reveal any differences between control and glycine-treated rats. Therefore, we conclude that infusion of glycine does not afford in vivo protection against acute ischemic renal injury in the rat. The in vitro protective effects of glycine therefore cannot be extrapolated to the in vivo situation.