Effect of familial hypertension on glomerular hemodynamics and tubulo-glomerular feedback after uninephrectomy

Familial hypertension, glomerular hemodynamic alterations, and dysregulatio n of tubulo-glomerular feedback (TGFB) have all been associated with the de velopment of chronic renal failure. In the present study we evaluated renal and glomerular hemodynamics and TGFB responses in healthy kidney donors ei ther with or without familial hypertension, before and after nephrectomy. Para-amino-hippurate plasma clearance (CPAH) and inulin plasma clearance (C Inu) were measured in 15 kidney donors before and 1 year after nephrectomy. All subjects were normotensive and were kept in a sodium-replete state. Bo th clearances were measured after 40 min of constant infusion of PAH and In u. as well as 20, 30, 50, and 60 min after the intravenous administration o f acetazolamide (5 mg/kg). Glomerular hemodynamics were calculated by means of the Gomez formulae. Nephrectomy caused the expected decreases in CPAH and CInu and increase in the filtration fraction tall P <.0001). The decrease in renal resistances o f the remaining kidney was greater at the afferent (- 24%, P =.0075) than a t the efferent arteriolar level (-17%, P <.0001). The TGFB activation was n ot altered by nephrectomy or by familial hypertension. Effective renal plas ma flow (ERPF) decrease after TGFB activation appeared earlier than glomeru lar filtration rate (GFR) decrease before (P =.01), but not after, nephrect omy (P =.48). The presence of familial hypertension was associated with inc reased glomerular pressure (P =.0004). This study suggests that uninephrectomy in healthy human subjects causes a greater decrease in afferent arteriolar resistances, but that TGFB response s are not quantitatively altered. Familial hypertension is associated with a tendency toward higher glomerular pressures. Am J Hypertens 2001;14: 121- 128 (C) 2001 American Journal of Hypertension, Ltd.