Renal excretory responses of taurine-depleted rats to hypotonic and hypertonic saline infusion

Male Wistar-Kyoto rats were given either tap water (control) or 3% β-alanine (taurine-depleted) for three weeks. To prepare for the kidney function studies, the animals were then implanted with femoral vessels and bladder catheters. Two days after surgery, each rat was given an intravenous infusion of saline at the rate of 50 μl/min and urine samples were collected at specific time intervals. An isotonic saline solution (0.9% NaCl) was infused for determination of baseline parameters and was followed by the infusion of a hypotonic saline solution (0.45% NaCl). Two days later, the infusion protocol was repeated in the same animals; however, a hypertonic saline solution (1.8% NaCl) was substituted for the hypotonic saline solution. Renal excretion of fluid and sodium increased in the control, but not taurine-depleted, rats during the hypotonic saline infusion. Interestingly, diuretic and natriuretic responses were similar between the groups during hypertonic saline infusion. The results suggest that taurine-depletion in rats affects renal excretory responses to a hypotonic, but not a hypertonic, saline solution.