Single nephron adaptations to partial renal ablation in cats.
Brown, Scott A., and Cathy A. Brown.
Department of Physiology and Pharmacology and Diagnostic
Laboratory, College of Veterinary Medicine, University of Georgia,
Athens, GA 30602
APStracts 2:0164R, 1995.
To evaluate remnant nephron hyperfiltration, cats underwent sham
surgery (group 1, N=6) or three-fourths nephrectomy (group 2, N=6).
Four to six weeks later, micropuncture studies demonstrated increases
(P<0.01) of single-nephron glomerular filtration rate (SNGFR) in
group 2 (28.1+/-2.8 nl/min verses 56.0+/-5.9 nl/min. In group 2 the
mean estimated glomerular capillary pressure of 74.0+/-1.7 mmHg
exceeded (P<0.01) the value for group 1 (62.6+/-1.4 mmHg). The
mean effective filtration pressure (EFPm) for group 2 (28.7+/-3.1
mmHg) was greater (P<0.05) than that in group 1 (20.8+/-1.9
mmHg). Similarly, the mean ultrafiltration coefficient Kf in group 2
of 2.03+/-0.24 nl/min/mmHg exceeded (P<0.05) the corresponding
value for group 1 of 1.35+/-0.06 nl/min/mmHg. Morphologic studies
demonstrated glomerular enlargement and mesangial matrix expansion in
group 2 (P<0.05). Proteinuria, as assessed by the urine protein
-to-creatinine ratio, was increased (P<0.05) following partial
renal ablation. These results demonstrate that increases in SNGFR in
feline remnant nephrons occur in association with glomerular
hypertension, glomerular hypertrophy, expansion of mesangial matrix,
and proteinuria and further, that the observed increases in SNGFR are
attributable to an augmentation of EFPm and Kf.
Received 17 October 1994; accepted in final form 12 May 1995.
APS Manuscript Number R603-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.