Increased ATP-ubiquitin-dependent proteolysis in skeletal muscles of tumor-bearing rats.

Little information is available on proteolytic pathways responsible for muscle wasting in cancer cachexia. Experiments were carried out in young rats to demonstrate whether a small (< 0.3% body weight) tumor may activate the lysosomal, Ca(2+)-dependent, and/or ATP-ubiquitin-dependent proteolytic pathway(s) in skeletal muscle.

Apolipoprotein A-I, A-IV and E synthesis in the liver of copper-deficient rats.

Copper deficiency induces hypercholesterolemia in the rat. This hypercholesterolemia is mainly due to an increase in apo E-rich high density lipoproteins (HDL1). The present study was undertaken to determine whether the HDL increase could be explained by altered low-molecular weight apolipoprotein (apo) synthesis in the liver.

Role of dietary propionic acid and bile acid excretion in the hypocholesterolemic effects of oligosaccharides in rats.

The aim of this study was to evaluate the influence of dietary propionic acid and bile acid excretion on the hypocholesterolemic effect of fibers. For this purpose, rats were adapted to a diet containing 10 g inulin, 10 g beta-cyclodextrin, or 2.5 g calcium propionate per 100 g diet.

Oxidative modification of triglyceride-rich lipoproteins in hypertriglyceridemic rats following magnesium deficiency.

Hypertriglyceridemia observed in magnesium (Mg)-deficient rats was associated with a significant increase in the very low-density lipoprotein (VLDL) plus low-density lipoprotein (LDL) fractions. The results from in vitro copper-induced lipid peroxidation, expressed in terms of conjugated dienes and thiobarbituric acid reactive substances content, showed that VLDL + LDL particles from Mg-deficient rats were more susceptible to oxidative damage than lipoproteins from control rats. These results suggest that the mechanism responsible for the atherogenicity and tissue damage characteristic of Mg deficiency may be mediated by an increased susceptibility of triglyceride-rich lipoproteins to peroxidation in hypertriglyceridemic animals.

Cecal fermentations in rats fed oligosaccharides (inulin) are modulated by dietary calcium level.

The influence of Ca on the fermentation of dietary oligosaccharides in the large intestine has been investigated in four groups of rats fed different semipurified diets: 1) fiber free, 3 g Ca/kg; 2) fiber free, 8 g Ca/kg; 3) 15% inulin, 3 g Ca/kg; or 4) 15% inulin, 8 g Ca/kg. The cecal fermentations were very low in rats fed the fiber-free diets and were not affected by the dietary Ca level. Rats fed the inulin diets had enlarged cecum with acidic fermentations, relatively rich in propionic acid.

Dietary magnesium affects susceptibility of lipoproteins and tissues to peroxidation in rats.

Magnesium (Mg)-deficient and control diets were pair-fed to weanling Wistar rats for 8 days. Plasma lipoproteins were separated into various density classes by sequential preparative ultracentrifugation. The extent of lipid peroxidation was measured in terms of thiobarbituric acid reactive substances in lipoproteins and tissue homogenates before or after iron-induced lipid peroxidation.