AJP - Renal Physiology, Vol 249, Issue 1 54-F61, Copyright © 1985 by American Physiological Society
Dietary protein intake conditions the degree of renal vasoconstriction in acute renal failure caused by ureteral obstruction
I. Ichikawa, M. L. Purkerson, J. Yates and S. Klahr
Whole kidney inulin (CIn) and PAH (CPAH) clearances were measured after
unilateral release of bilateral ureteral obstruction (BUO) of 24-h duration
in rats fed for 4 wk isocaloric diets containing either 40% casein (high
protein diet) or 6% casein (low protein diet). Values for CIn and CPAH were
markedly depressed in both groups but to a greater extent in high
protein-fed rats, averaging less than 60% of values measured in low
protein-fed animals. Captopril, an inhibitor of the angiotensin I
converting enzyme, increased CIn and CPAH markedly but comparably in high
or low protein fed rats. Micropuncture studies performed after unilateral
release of BUO in another group of rats fed a high or a low protein diet
revealed lower levels of glomerular plasma flow rate (QA) and single
nephron glomerular filtration rate (SNGFR) in rats fed a high protein diet.
Values for renal arteriolar resistances were nearly twofold in high as
compared with low protein-fed animals. Infusion of OKY-1581, an inhibitor
of thromboxane A2 synthetase, increased both QA and SNGFR, decreased
arteriolar resistances, and increased glomerular capillary ultrafiltration
coefficient in high but not in low protein-fed rats. Urinary thromboxane B2
excretion per milliliter of GFR was greater in rats fed a high protein diet
than in those fed a low protein diet after release of BUO but not in normal
rats. In normal rats infusion of OKY-1581 did not increase CIn or
CPAH.(ABSTRACT TRUNCATED AT 250 WORDS)
