Efficient Hepatic Uptake of Chylomicron Remnant Cholesterol in Rats with a Portacaval Anastomosis

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Abstract
Portacaval-shunted and sham-operated male rats, fed ad libitum and of similar weight, were studied 2-3 wk after surgery. At this time serum cholesterol levels did not differ significantly between the 2 groups, whereas serum triacylglycerols and phospholipids were lower in the shunted group. These animals also showed an increased serum bile acid level and an increased serume estradiol to testosterone ratio. The metabolism of native chyle labeled with [3H]cholesterol and [14C]linoleic acid or of preformed chylomicron remnants with the same labeling was studied in the groups of rats. Ten min after i.v. injection of chylomicron remnants 10.6 .+-. 0.5% (means .+-. SEM [standard error of mean], n = 8) of the injected [3H]cholesterl nd 7.6 .+-. 0.4% of the [14C]linoleic acid were found per 1 g liver in the portacaval-shunted rats; the corresponding figures in the sham-operated group (n = 8) were 6.4 .+-. 0.4% and 4.9 .+-. 0.3%, respectively (P < 0.001 for both 3H and 14C). Thus, despite a > 40% reduction of liver weight induced by the shunting procedure, the total liver uptake of chylomicron remnants was not significantly decreased. The uptake of chylomicron lipids per unit liver weight was normal in the atorphic livers of portacaval-shunted rats also when very large loads of chyle were administered.