Showing papers on "Sodium propionate published in 1988"

Hypocholesterolaemic effects of dietary propionate: studies in whole animals and perfused rat liver.

Abstract: In adult male rats fed a non-purified diet supplemented with 5 % sodium propionate, plasma cholesterol concentrations were significantly depressed. Although liver cholesterol was increased by feeding

The roles of hepatic nerves in the reduction of food intake as a consequence of intraportal sodium propionate administration in sheep.

Abstract: Like other mammals, ruminants can also control their food intake. One of the potential sites where feed-back signals arise is the liver. We have already shown in our previous study that intraportal administration of propionate depresses intake and that this action is dependent on an intact nerve supply to the liver because sectioning the hepatic plexus abolishes the effect of propionate. In the following work the relative importance and the possible roles of different hepatic nerves were investigated. Three-hour continuous infusions of sodium propionate or saline into the hepatic portal vein of sheep were carried out following applications of different surgical procedures and food intakes were measured. In experiment 1 bilateral splanchnotomies were sufficient to prevent the effect of propionate on food intake. The subsequent total hepatic denervations also resulted in the removal of the depressing effect of propionate. Experiment 2 was designed to compare the involvement of the splanchnic afferents from the liver and the hepatic vagal afferents. Intraportal propionate was demonstrated to depress feeding in the intact animal whereas splanchnic nerve blockade with local anaesthetic removed this effect. Paradoxically selective hepatic vagotomy also abolished this effect. It was concluded that there may be more than one pathway involved in transmitting information from the liver to the central nervous system. Possible implications of the results are discussed and attempts are made to explain the mechanism of action and compare different theories by other workers.

Reductive Carboxylation of Propionate to Butyrate in Methanogenic Ecosystems

Abstract: During the batch degradation of sodium propionate by the anaerobic sludge from an industrial digestor, we observed a significant amount of butyrate formation. Varying the initial propionate concentrations did not alter the ratio of maximal butyrate accumulation to initial propionate concentration within a large range. By measuring the decrease in the radioactivity of [1-14C]butyrate during propionate degradation, we estimated that about 20% of the propionate was converted to butyrate. Labeled butyrate was formed from [1-14C]propionate with the same specific radioactivity, suggesting a possible direct pathway from propionate to butyrate. We confirmed this hypothesis by nuclear magnetic resonance studies with [13C]propionate. The results showed that [1-13C]-, [2-13C]-, and [3-13C]propionate were converted to [2-13C]-, [3-13C]-, and [4-13C]butyrate, respectively, demonstrating the direct carboxylation on the carboxyl group of propionate without randomization of the other two carbons. In addition, we observed an exchange reaction between C-2 and C-3 of the propionate, indicating that acetogensis may proceed through a randomizing pathway. The physiological significance and importance of various metabolic pathways involved in propionate degradation are discussed, and an unusual pathway of butyrate synthesis is proposed.

Osmotic and activity coefficients of the sodium salts of formic, acetic and propionic acids

Abstract: Osmotic and activity coefficients are reported for the sodium salts of formic, acetic and propionic acids to the limits of their solubilities. Hydration of the “second kind” appears to increase with the length of the hydrocarbon chains. The onset of micelle formation is indicated in the more concentrated sodium propionate solutions.