Abstract
Abstract
Intestinal carbohydrate uptake and utilization were studied before and during the perfusion of the canine jejunal lumen with food. Under conditions of normal oxygen consumption (1.8 ml O2/min/100 g) and blood flow (46.4 ± 3.5 ml/min/100 g), intestinal glucose uptake was low (2 mg/min/100 g) and glucose utilization was aerobic. When food was present in the lumen, there was a 15% increase in intestinal metabolism, as measured by oxygen consumption, while lactic acid production increased threefold. This increase in lactic acid production was not due to a shift in glycolysis toward lactic acid synthesis as the venous lactic acid/pyruvic acid concentration ratio actually decreased. Intestinal glucose utilization was offset by carbohydrate absorption as glucose uptake from arterial blood decreased. The data suggest that a relatively greater proportion of intestinal energy demand is met by glycolysis during the absorption of nutrients than at rest and supports the findings of other investigators that a portion of absorbed glucose is metabolized. In addition, the study indicates that intestinal glucose metabolism does not terminate in lactic acid synthesis as suggested by a previous study.
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