Effects of systemic hypertension, antidiuretic hormone, and prostaglandins on remnant nephrons.

Renal function was evaluated in normal and after 30 days of 5/6 renal mass reduction (CRF) in Munich-Wistar (MW) rats, spontaneously hypertensive rats with superficial glomeruli (EPM), and in Brattleboro rats with congenital diabetes insipidus (DI). Mean arterial pressure was higher in EPM-Control and EPM-CRF rats as compared with MW and DI rats. MW and EPM rats with CRF showed increases of 120% and 196%, respectively, in single nephron glomerular filtration rate as compared with their controls. However, DI rats with CRF did not show any increase in single nephron glomerular filtration rate as compared with the control group. Therefore, the data suggest that the presence of hypertension enhances the adaptive mechanisms on remnant kidney's function. Conversely, in the absence of antidiuretic hormone, adaptive mechanisms of remnant nephrons did not occur. In addition, it was observed that rats with CRF submitted to prostaglandin blockade with indomethacin showed for MW rats a 55% and 20% reduction in ultrafiltration coefficient and in single nephron glomerular filtration rate, respectively. Decreases of 60% and 30% in ultrafiltration coefficient and single nephron glomerular filtration rate, respectively, were observed for EPM rats. In contrast, DI rats did not show any alteration on renal function after indomethacin. It seems, therefore, that prostaglandins play a role in remnant nephron function of MW and EPM rats, but in the absence of antidiuretic hormone, prostaglandins do not affect remnant glomerular hemodynamics.