APStracts 2:0066F, 1995.

Autoregulation of zonal glomerular filtration rate and renal blood flow in shr. Wang, Xuemei, Knut Aukland, Jarle Ofstad, and Bjarne M Iversen. Renal Research Group, Medical Department A, Haukeland Hospital and Department of Physiology, University of Bergen, Bergen, Norway

APStracts 2:0066F, 1995.

Autoregulation of total and zonal GFR in outer, middle and inner cortex was estimated in hypertensive rats (SHR) from the tubular uptake of 125Iodine labeled aprotinin (125IAp) injected at control renal arterial pressure (RAP), and 131IAp injected at reduced RAP in left kidney. Normotensive rats (WKY) were used as controls. RBF autoregulation was reset to higher pressure levels in SHR. When RAP was lowered close to the lower pressure limit of RBF autoregulation, total GFR was reduced to 89.5+/-3.1% and 88.1+/-3.3% of control in WKY 10 wk and 40 wk, and to 87.7+/-2.3% and 88.0+/-2.2% in SHR 10 and 40 wk. In WKY the fall of GFR in the three cortical layers was not different during RAP reduction. In 10 and 40 week old SHR, however, the GFR fell significantly less in inner than in middle and outer cortex (p<0.05). We conclude that autoregulation of GFR is most efficient in the inner cortex of SHR. In all animals GFR was less well autoregulated than RBF.

Received 11 October 1994; accepted in final form 10 April 1995.
APS Manuscript Number F360-4.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on  2 May 1995.