METABOLIC BASIS OF CATECHOLAMINE-INDUCED WATER TRANSPORT IN EVERTED GUT SACS OF MOUSE

Abstract

1. Catecholamine-induced water transport was measured using an everted gut sac technique. Adrenaline, noradrenaline and isoprenaline induce dose-dependent increases in water transport by the proximal intestinal sacs. Use of selective adrenergic agents revealed the possible involvement of alpha 1- and beta 2-receptors in mediation of catecholamine stimulation of water transport in this segment. 2. Inhibition of glycolysis reduced the effect mediated through alpha 1-receptors, while the inhibition of oxidative phosphorylation blocked the beta 2-receptor mediated increase in water transport. 3. Basal transport of water was also significantly reduced by inhibition of glycolysis but was significantly elevated by blockage of oxidative phosphorylation. 4. Suppression or stimulation of glycolysis was paralleled by similar changes in lactic acid release from the gut wall. 5. It is concluded that the energy for the catecholamine-induced water transport is contributed by glycolysis and oxidative phosphorylation coupled to alpha 1- and beta 2-receptors, respectively. Under basal conditions water transport is mainly dependent on glycolysis in the segment of intestine examined.