THE RENAL HEMODYNAMIC-RESPONSE TO AN ORAL PROTEIN LOAD IS NORMAL IN IGA NEPHROPATHY

The study was devised to explore the effects of an acute oral protein load on renal hemodynamic response in patients with IgA nephropathy (I gAN). The study was performed in 10 proteinuric IgAN patients (800 +/- 300 mg/day) and in 20 healthy controls (matched by sex, age, BMI, BSA , plasma creatinine, plasma urea, urinary urea and protein intake). Bl ood pressure and creatinine clearance were nearly identical in the two groups. GFR and RPF, measured as the clearance of inulin and of p-ami nohippurate (PAH) were studied before and after a meat meal which prov ided 2 g of protein/kg BW. Following the protein load, renal reserve, percent renal reserve and postmeal cumulative changes of GFR were not significantly different in IgAN and controls. Filtration fraction (FF) at baseline was significantly higher (p < 0.01) in IgAN than in contr ols (25.5 +/- 1.41 vs. 19 +/- 2%). Postmeal hyperemia and hyperfiltrat ion did not affect FF in either group. Filtration capacity in IgAN was lower (p < 0.02) than in controls (117 +/- 5.6 vs. 137.9 +/- 7.0 ml/m in x 1.73 m(2)), whereas the percent of filtration capacity utilized a t rest was identical in controls and in IgAN. Creatinine clearance ove restimated GFR in IgAN. The data indicate that renal hemodynamic respo nse to proteins in IgAN is normal.