Dietary fish oil interferes with renal arachidonic acid metabolism in rats: correlations with renal physiology.

Dietary fish oil has been reported to have both beneficial and deleterious effects in animal models of renal disease, which may be related to alterations in renal eicosanoid metabolism. The influence of dietary fish oil on glomerular and renal tubular responses that are linked to arachidonic acid metabolism was examined. Dietary fish oil had antidiuretic and antinatriuretic effects, which correlated with reduced renal cortical endogenous prostaglandin E2 (PGE2). Fish oil altered the renal balance of dienoic prostacyclin (PGI2) to thromboxane (TXA2) in favor of vasodilation, which may explain the observed exaggerated compensatory increases in glomerular function in response to uninephrectomy. Intact rats fed fish oil for 6 months developed proteinuria and impaired glomerular filtration rates (GFR). These deleterious effects were associated with evidence of increased renal lipid peroxidation. These results suggest that dietary fish oil modifies glomerular and renal tubular function in rats, and worsens age-associated proteinuria and declines in GFR. These effects may reflect the impact of dietary fish oil on renal fatty acid composition and arachidonic acid metabolism.