The action of bile salts on fluid and glucose movement by rat and hamster jejunum, in vitro.

Abstract

AbstractEverted sacs of rat and hamster jejunum were used to measure, simultaneously, fluid and glucose movement in the presence of various concentrations of bile salts. Low concentrations of sodium taurocholate or glycocholate did not affect the rates of fluid absorption or transport by either rat or hamster jejunum. Under these conditions, in some cases, while glucose absorption was unaffected, glucose transport was inhibited. High concentrations of bile salts reduced fluid and glucose absorption and transport by both rat and hamster jejunum. Although the transport of glucose against a concentration gradient is completely inhibited at low concentrations of bile salts with rat jejunum, it still occurs with hamster jejunum even in the presence of high bile salt concentrations. In the absence of glucose in the incubation medium, the rates of fluid absorption by rat and hamster jejunum were greatly reduced. Under these conditions, fluid transport by rat jejunum was completely abolished, whereas fluid transport by hamster jejunum was greatly reduced, but not completely inhibited. However, addition of bile salts to the glucosefree incubation medium did produce a complete inhibition of fluid absorption and transport by both rat and hamster jejunum. Bile salts, within the concentration range used in this investigation, have no effect upon glucose utilization and lactic acid production by either rat or hamster jejunum. Sodium taurocholate and glycocholate, at the low concentration of 1 mM, reduced the ATP levels in both rat and hamster jejunal sacs. This reduction of ATP levels in whole sacs was also observed to occur in the mucosal layer in the presence of low concentrations of bile salts. A greater reduction in tissue ATP levels was observed when the bile salt concentration was increased. The amount of ATP in unincubated rat and hamster jejunum was reduced by approximately 40% when incubated in bicarbonate saline containing glucose. Tissue ATP levels were also reduced when sacs were incubated in a glucose‐free medium, a greater reduction being observed in rat jejunum. In the absence of glucose, bile salts were capable of decreasing ATP levels in hamster, but not in rat jejunum. The effects of bile salts on fluid and glucose movement by rat and hamster jejunum were discussed in relation to tissue energy sources for these processes. Also, the possible role played by bile salts in regulating the transference of various substances across the intestinal wall was discussed.