Renal nutrients uptake and brush border membrane enzymes in cholesterol fed guinea pigs

The effect of dietary cholesterol load on the reabsorption of nutrients and the enzyme and chemical characteristics of renalbrush-bordermembrane (BBM) was evaluated in guineapigs. The transport of d-glucose and amino acids into the renal BBM vesicles of experimental animals was significantly (P < 0.001) decreased. Vmax of leucine aminopeptidase decreased without alteration in Km; however, both the Km and Vmax of alkaline phosphatase and maltase decreased in renalmembrane in response to cholesterol load. The alterations in the chemical architecture of the membrane could possibly be responsible for the observed aberrations in the kidneys of cholesterol-fed animals

Towards the mechanism of protection against indomethacin induced gastro-intestinal ulceration by naloxone

Activities of lysosomal hydrolases have been evaluated in relation to indomethacin and naloxone, using purified lysosomal fractions from rat intestinal mucosa. Indomethacin treatment significantly decreased (p less than 0.001) lysosomal enzyme activities in purified lysosomes, while an increase in the activities was observed in intestinal homogenates. However, indomethacin could not affect lysosomal system in animals pretreated with naloxone, thereby establishing that naloxone neutralises the effect of indomethacin

Enzymatic and transport studies in cholesterol-fed Guinea Pigs using Intestinal Brush Border Membrane Vesicles

The intestinal absorptive and digestive functions using the brush border membrane (BBM) vesicles were evaluated in guinea pigs receiving cholesterol-supplemented diet for 12 weeks. The Na+-gradient-dependent transport of D-glucose (p < 0.001), L-alanine and L-phenylalanine (p < 0.01) was decreased significantly the BBM of cholesterol-fed animals. The maximal velocity (Vmax) value of the sucrase and leucine aminopeptidase was decreased without any change in the affinity constant (Km) value, demonstrating that the enzyme contents were reduced in response to cholesterol-rich diet. However, both the Km and Vmax values of the alkaline phosphatase decreased markedly, suggesting that a new enzyme of increased substrate affinity had been formed due to intestinal adaptation of cholesterol load in diet. The present study demonstrated that cholesterol feeding caused a significant alteration in nutrients absorption, membrane enzymes and chemical composition of the small intestine