Sugar transport in the small intestine of obese hyperglycemic, fed and fasted mice

1. The in vitro transport of 3-0-methyl-D-glucose was measured in the small intestine of obses-hyperglycemic (ob/ob) mice and their lean littermates, fed or fasted for 48 hrs. 2. Transport was much increased in the jejunum of obese animals and, to a lesser extent, in obese mice on a chronic restricted diet. 3. Kinetic studies indicate that the Vmax of transport was significantly greater in obese than in lean mice, whether fed or fasting. Fasting increase the Vmax in lean but not in obese animals. These changes were more prominent in the jejunum. The apparent Km of transport was the same in all four groups. 4. These findings are discussed in relation to the increase in intestinal absorptive functions in diabetes and in some conditions of food restriction or starvation. The results are consistent with the hypothesis that the effects of diabetes and of starvation on intestinal sugar transport reflect an alteration in the same controlling factor.