Stop-flow study of renal function in conscious water snakes (natrix sipedon)

1. 1. Stop-flow evaluation of renal function was carried out in conscious water snakes, Natrix sipedon. 2. 2. Distal inulin urine-to-plasma (U/P) ratio increased while relative sodium U/P ratio (U/P_Na/U/P_In) decreased, suggesting distal reabsorption of sodium and water. 3. 3. Increases in relative sodium and potassium U/P ratios occurred in the proximal regions. 4. 4. Decrease in inulin U/P ratio occurred in proximal region, suggesting a net addition of water to the tubular lumen. 5. 5. Relative urate U/P ratio tended to increase in same region as sodium and potassium peaks. Although this increase was not statistically significant, it suggested a possible interaction of sodium, potassium and water movements with urate movement in this region. This possibility in discussed.