Renal Excretion of Stevioside in Rats

The renal excretion of stevioside, a glycoside extracted from the leaves of Stevia rebaudiana, and its effect on renal excretion of several substances, was studied through clearance techniques in Wistar rats. After a control period, stevioside was infused iv at four concentrations (4, 8, 12, and 16 mg/kg). During all the experiments no significant changes in inulin clearance (CIn) were observed. The stevioside infusion induced a significant increase in the p-aminohippuric acid clearance (CPAH), fractional sodium excretion (FeNa+), urinary flow as percent of glomerular filtration rate (V/GFR), and glucose clearance (CG) when compared to controls, but these effects were absent with the dose of 4 mg/kg. The stevioside clearance (CS) was higher than the CIn and lower than the CPAH at all the doses employed in this study. These results indicate that the stevioside is secreted by renal tubular epithelium and induces diuresis and natriuresis and a fall in renal tubular reabsorption of glucose.