Activity of peroxisomal enzymes, and levels of polyamines in LPA-transgenic mice on two different diets.

Background: In man, elevated levels of plasma plipoprotein (a) (Lp(a)) is a cardiovascular risk factor, and oxidized phospholipids are believed to play a role as modulators of inflammatory processes such as atherosclerosis. Polyamines are potent antioxidants and anti-inflammatory agents. It was therefore of interest to examine polyamines and their metabolism in LPA transgenic mice.

Effects of dietary polyamines and clofibrate on metabolism of polyamines in the rat.

The activities of catalase, polyamine oxidase, diamine oxidase, ornithine decarboxylase, and peroxisomal beta-oxidation were assayed in homogenates from liver and small intestinal mucosa of rats which had been fed either a diet very low in polyamines or a diet containing five times the levels of dietary polyamines (putrescine, spermine, and spermidine) found in a standard rat diet. In rats fed the high polyamine diet, hepatic activities of catalase and polyamine oxidase were significantly decreased. Levels of the other activities were unchanged, except that intestinal ornithine decarboxylase was decreased.

Metabolism of acetyl-CoA by isolated peroxisomal fractions: formation of acetate and acetoacetyl-CoA.

Liver peroxisomal fractions, isolated from rats treated with clofibrate, were shown to hydrolyze added [1-14C]acetyl-CoA to free [1-14C]acetate. [1-14C]Acetyl-CoA was, however, also converted to [14C]acetoacetyl-CoA. This reaction was inhibited by added ATP and by solubilization of the peroxisomes.

Synthesis of phosphoenolpyruvate [correction of phosphoenolphosphate] from pyruvate in rat skeletal muscle.

1. The activity of pyruvate kinase, malic enzyme, phosphoenolpyruvate carbonoxykinase and pyruvate carboxylase was measured in muscle tissue. 2.