Male rats were submitted for 3 wk either to portacaval shunt or to portacaval transposition. In both cases, sham-operated pair-fed rats served as controls. After an overnight fast, insulinemia was similar in all groups, but glucagonemia was significantly higher (by 65%) and serum glucose significantly lower (by 35%) in rats with a portacaval shunt. The lipid metabolism of epididymal adipose tissue was studied in vitro, as well as in vivo. In rats with a portacaval shunt, in vitro lipogenesis from [U-14C]glucose, [1-14C]acetate, or 3H2o was 60-80% lower than in sham-operated pair-fed controls. Twice as much in vitro basal lipolysis could be determined. In addition, in vivo lipogenesis from 3H2O was markedly decreased (6 times). By contrast, in rats with portacaval transposition, in vitro lipogenesis was higher (by 80-140%) and basal lipolysis lower (by 63%) than in pair-fed controls. Thus, even when the nutritional state was taken into consideration, the type of portal diversion was the determining factor in influencing lipid metabolism in epididymal adipose tissue.

No abstract

Fractional clearance of colloidal gold particles (k), liver weight and hepatic cytochrome P-450 were measured in rats with portacaval shunt and in rats with portacaval shunt plus arterialization of the hepatic stump of the portal vein. The effects of enzyme induction by phenobarbital was studied in both groups. Total arterialization of the liver provides a probably normal hepatic blood flow and seems to protect the liver from post-shunt atrophy. Nevertheless, in both arterialized and shunted rats, the cytochrome P-450 concentration was significantly lower than in controls. The same results were obtained after treatment by phenobarbital. These findings suggest that normal hepatic blood flow and oxygen supply are not the main determinant of a normal activity of the hepatic microsomal bio transformation system. Substances present in portal blood would probably be necessary in maintaining hepatic cytochrome P-450 level.

Total hepatic blood flow and ammonia tolerance test have been measured in dogs before and after portacaval shunt. In spite of a very significant decrease of more than 50% in hepatic blood flow, the hepatic extraction efficiency remained normal. A good correlation was observed between maximal blood ammonia level during tolerance test and total hepatic blood flow. No correlation was found between blood ammonia level and hepatic extraction efficiency. In shunted dogs, the hyperammonemia during the ammonia tolerance test seemed to be determinated by the hepatic blood flow variation more than by the liver parenchymal damage.

The secretion of acid, pepsin, chondroitin sulfate and glycoproteins from mucus have been studied in four Heidenhain pouch dogs, under basal condition and during stimulation with histamine, a gastrin- like pentapeptide and a cholinergic drug. Histamine and the gastrin analogue stimulate acid and, to a lesser extent, pepsin secretion, and they inhibit mucus secretion; cholinergic stimulation increases the output of acid, chondroitin sulfate, pepsin and glycoproteins of the mucus. No qualitative changes in the secretion of peptic or mucous cells are observed.