The nature of renal hemodynamic response to a large carbohydrate-rich meal and the associated renal excretory functions were examined. Seven normal subjects were studied after ingestion of 300 g of rice meal. Five healthy men served as a time control. After eating the test meal, the mean creatinine clearance began to rise and became significantly higher in the 2nd hour compared with the control (118 +/- 7 vs. 91 +/- 3 ml/min/1.73 m2; p less than 0.01). Urinary excretion rates of sodium and chloride after the meal were significantly higher compared with those in the premeal period. Blood glucose concentrations rose significantly following the meal. The postprandial plasma levels of amino acids did not vary significantly compared with the premeal values. These results demonstrate that rice meal ingestion increased glomerular filtration rate via a mechanism(s) different from the protein-induced glomerular hyperfiltration.