AJP - Renal Physiology, Vol 256, Issue 5 843-F851, Copyright © 1989 by American Physiological Society
Fish oil diet decreases prostacyclin and increases resistance in isolated rat kidneys
B. L. Kasiske, M. P. O'Donnell and W. F. Keane
Department of Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis 55415.
The mechanisms whereby diet-induced alterations in fatty acids may affect
renal structure and function are unknown. Kidneys from rats fed chow
supplemented with 18% (wt/wt) coconut oil (CO, n = 8), sunflower seed oil
(SO, n = 7), or fish oil (FO, n = 8) were isolated from systemic influences
of the diets and perfused with a cell-free medium. The FO diet caused a
twofold reduction in prostaglandin (PG) I2 (urine excretion of 6-keto-PGF1
alpha) compared with SO and CO. Urine PGE2 and thromboxane (Tx) B2 were
similar in the three diet groups. There was a 22% reduction in perfusate
flow associated with the decrease in PGI2 in the FO group (42 +/- 6
ml.min-1.g-1) compared with the CO (54 +/- 7 ml.min-1.g-1) and SO (54 +/- 8
ml.min-1.g-1) groups (mean +/- SD, P less than 0.05). The glomerular
filtration rate (GFR) was similar in the three groups during the initial
base-line determination but subsequently declined to a greater degree in
the FO group. Morphologically, tubular injury was most extensive in the FO
group, and the distribution of the injury indicated that it was caused, at
least in part, by ischemia. The decline in GFR and the degree of
histological injury were more closely linked to the diminished PGI2
production. Thus dietary FO supplementation caused decreased renal PGI2,
increased renal vascular resistance, and an increased susceptibility to
ischemic tubular cell injury in the isolated kidney.
