Galactose increases microvillus development in mouse jejunal enterocytes

Abstract

1. 1. Mice fed low carbohydrate and galactose-containing diets have been used to determine both positional and temporal aspects of microvillus development during enterocyte migration from intestinal crypts towards the tips of jejunal villi. 2. 2. The positional dependence of microvillus growth was found to be similar in mice fed low carbohydrate (3.0 kcal/g), galactose-contaning lipid substituted (2.9 kcal/g) and galactose-containing agar substituted (5.1 kcal/g) diets. The daily calorific intake by mice fed these diets was about 10.4 kcal/mouse. The maximal microvillus length reached by enterocytes fed galactose was nearly twice that measured in mice fed the low carbohydrate diet. 3. 3. Enterocyte migration rate in mice fed the low carbohydrate and the high calorie galactose-containing diet was twice that measured in mice fed the low calorie galactose-containing diet. These changes were not associated with any noticeable alteration in the size of intestinal crypts. 4. 4. Changes in maximal microvillus length (M) can be predicted from the equation M = 0.0016 CD + 0.073 CD/ R, where CD and R refer to crypt depth and enterocyte migration rate respectively, Smith M. W. and Brown D. (1989). Dual control over microvillus elongation during enterocyte development. Comp. Biochem. Physiol. 93A, 623–628. Substituting measured values for CD and R in this equation revealed a specific capacity of galactose to potentiate microvillus development when presented in the form of a high calorie diet. 5. 5. The possibility that galactose, which is poorly metabolized in mice, can increase microvillus expression by interfering specifically with some aspect of carbohydrate metabolism is discussed.