Monosaccharide transport by the small intestine of lean and genetically obese (ob/ob) mice

The effect of the obese (ob/ob) genotype on monosaccharide transport in mouse small intestine has been examined, using several different methodologies, at various stages in the development of the syndrome. Evidence for an elevation of the total capacity of the small intestine for monosaccharide transport was found at 10, 20 and 40 weeks of age in obese mice by comparison with lean controls, the difference being most prominent at 20 weeks of age after the hyperphagic phase of the syndrome had ceased. No substantial alteration in transport, expressed per gram dry weight of intestine, either from luminal perfusion studies or from measurements of the kinetics of influx across the brush border was found in adult obese mice compared with lean controls. It is concluded that, in obese mice, the increased capacity of the intestine for monosaccharide transport compared with lean mice was due to increases in the total intestinal dry weight, and in the intestinal dry weight per centimetre, and not to changes in carrier activity per unit dry weight of intestine.