Intestinal fat malabsorption in the uremic rat.

In the past we have shown that patients with chronic renal failure (CRF) on hemodialysis show evidence of intestinal malabsorption of fat. The present study was designed to verify this finding in an animal model. Male rats weighing +/- 200 g were studied. Uremia (U) was induced by 2-stage subtotal (5/6) nephrectomy. Control (C) animals were sham-operated. Fat absorption was studied after 6 weeks of uremia with the oral fat loading test. Twenty percent intralipid (0.25 g/100 gBW) was given by gastric tube feeding to fasting animals and the appearance of chylomicrons (CHYL) and the rise of triglycerides (TG) in the serum was followed for 5 hrs. In order to isolate the effect of fat absorption, an additional group of U and C animals was pretreated with orotic acid and triton, thus blocking hepatic TG synthesis and neutralizing peripheral lipoprotein lipase activity. The absorption of CHYL was significantly (p less than 0.01) impaired in all U animals and averaged 43 and 70 percent of that of the C animals, 1 and 2 hrs after the load respectively. The rise in serum TG did not differ from C in mildly U animals (Scr 1.0 +/- 0.04). In the more severely uremic animals (Scr 2.6 +/- 0.2), however, pretreated with orotic acid and triton, the rise in serum TG was far less (p less than 0.01) than in C animals (111 +/- 26-903 +/- 111 delta % V.780 +/- 170-5032 +/- 746 delta %) 1 and 5 hrs after the load.(ABSTRACT TRUNCATED AT 250 WORDS)