Role of motilin in the control of intestinal absorption, and gastric and biliary secretions in the rat.

The effects of motilin on proline absorption and gastric and biliary secretions were examined in the rat. Prolonged intravenous administration of motilin (50 pmol/kg/min) significantly inhibited (P < 0.05) proline transport across the jejunum and reduced basal acid secretion to 40% of control value. The same concentration of motilin induced choleresis and increased bile output by 32%. Incubation of intestinal strips with different concentrations of motilin produced a dose-dependent inhibitory pattern of proline accumulation in the intestinal cells.

Age influence on intestinal taurine transport in mice.

Taurine plays a role in neurologic development and neuromuscular function. The high need for taurine during development, and the low capacity for endogenous biosynthesis make its intestinal handling very important. In this in vitro study, we investigated the uptake of taurine by intestinal strips obtained from adult, 10-day and 20-day-old mice. Intestinal strips from adult, 10-day and 20-day-old mice accumulated taurine against a concentration gradient. Moreover, the capacity of the intestinal cells to concentrate taurine decreased with age. A major component of the transport process was carrier-mediated and Na-dependent. Analysis of the kinetics of taurine uptake revealed that Vmax decreased as the animals grow older without a significant change in apparent Kt. It is concluded that as mice grow older their intestinal capacity to absorb taurine decreases.

Functional and structural changes in the jejunum of the rat following cysteamine and stress-induced duodenal ulcer.

The effects of cysteamine and stress-induced duodenal ulcer on the functional and structural properties of the rat jejunum were investigated. The absorptive capacity of the jejunum was determined using alanine as the permeant solute and the single-pass perfusion technique. A statistically significant decrease (p < 0.01) in alanine absorption was observed after 8 h and 3 days of duodenal ulcer induction by stress and cysteamine respectively. However, alanine transport measured 7 days after cysteamine or stress ulcer induction showed no significant change from control values. Cysteamine and stress-induced duodenal ulcer did not show any significant change in water absorption across the jejunum when measured after 8 h, 3 and 7 days of ulcer induction. Microscopically, the jejunum of rats with 3-day cysteamine-induced ulcer exhibited diffuse type of apical derangements with excessive swelling of the villi and progressive degenerative changes. No such changes were noticed on the 7th day nor in the jejunum of the rats with stress-induced duodenal ulcer. The results suggest that cysteamine-induced duodenal ulcer produces an inhibition in the absorptive capacity of the jejunum which is time-dependent and reversible.