RENAL HEMODYNAMIC-RESPONSE TO ERYTHROPOIETIN-INDUCED POLYCYTHEMIA IN 5 6-NEPHRECTOMIZED RATS IS DIFFERENT FROM NORMAL RATS/

The effects of recombinant human erythropoietin (rHuEPO)-induced polyc ythemia on renal function and glomerular hemodynamics were evaluated i n Munich-Wistar rats (MW+EPO) before and after infusion of indomethaci n; the rHuEPO effects on total renal function were also evaluated in 5 /6 nephrectomized (CRF) MW and spontaneously hypertensive rats (MW-CRF +EPO and SHR-CRF+EPO, respectively). In normal MW rats, rHuEPO (300 IU /kg BW, 3 x /week, during 2 weeks) induced elevation in MAP, with main tenance of GFR, paralleled by superficial vasodilatation and elevation in SNGFR, suggesting cortical blood redistribution. These hemodynamic alterations induced by rHuEPO were blunted by indomethacin, suggestin g a participation of the vasodilator prostaglandins in the renal compe nsatory mechanism of polycythemia. Elevation in MAP and reduction in G FR occurred in the MW+CRF+EPO group compared with the group receiving vehicle. In contrast, the SHR-CRF+EPO presented a reduction in MAP and maintenance of GFR, suggesting different rHuEPO effects depending on previous renal function and/or hypertensive state.