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

Abstract

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 (V_max) value of the sucrase and leucine aminopeptidase was decreased without any change in the affinity constant (K_m) value, demonstrating that the enzyme contents were reduced in response to cholesterol-rich diet. However, both the K_m and V_max 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.