Study on lipid absorption in uraemia

While the occurrence of morphological and functional small intestinal alterations in chronic uraemia is well established, analyses of intestinal lipid utilization are rare. In the present study faecal fat excretion in chronically uraemic humans and rats and the reesterification of a long-chain fatty acid in the mucosa of the small intestine of uraemic rats were investigated. -Reesterification of 14C-palmitic acid in the intestinal mucosa of rats with chronic uraemia produced by 5/6-nephrectomy (BUN 37.8 +/- 12.8 mg/100 ml, serum creatinine 3.0 +/- 0.44 mg/100 ml) was found to be significantly lower (374.2 +/- 166.8 mumol/mg protein x h) than in controls (604.9 +/- 274.2 mumol/mg protein x h) pointing to a disturbance of the intracellular process of absorption of long-chain fatty acids. However, the mean daily fat excretion in the faeces of chronically uraemic rats fed a diet with normal (4.2 per cent) or relatively high fat content (10 and 15 per cent) was not increased. In 20 patients with chronic renal insufficiency (BUN 75.9 +/- 35.9 mg/100 ml, serum creatinine 7.5 +/- 2.8 mg/100 ml) the faecal fat excretion was within the normal range (4.2 +/- 1.2 g/day). These results indicate a sufficient compensation of the impaired intestinal reesterification of fatty acids by the large functional reserve of the small intestine.