RAT AND HAMSTER JEJUNUM DURING TRANSINTESTINAL TRANSPORT INVITRO

By using the jejunal tract of rat and hamster intestine, net fluid trans-intestinal transport in the everted sac incubated in vitro at 28 °C and at 38 °C has been determined. In the scraped mucosa wet weight/dry weight ratio, cell water, sodium and potassium concentration have been detected in vivo and in vitro, throughout the incubation time, at the two different temperatures. Under all these conditions ATP, ADP and AMP levels have been determined in total intestine and in scraped mucosa. In rat jejunum incubated in vitro at 38 °C transintestinal fluid transport continuously decreases during 1-h experiment; in the same time the enterocyte gains sodium, dilutes cell potassium and swells, whereas its energy charge is dramatically reduced. All these parameters are constant in rat jejunum incubated at 28 °C and in the hamster incubated both at 28 °C and at 38 °C throughout the experiment. An inadequate diffusion of oxygen into the enterocyte, could tentatively explain experimental results obtained on rat jejunum at 38 °C. Under all tested conditions, energy charge and intracellular potassium are lower in conditions in vitro than in those in vivo; the contrary happens for cell sodium and swelling. The oxygenation of the intestine in vitro, lower than the one in vivo, could explain the different behaviour found in the two experimental conditions. © 1979 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.