Effect of Changes in the Osmolality of the Luminal Fluid on Water and Glucose Transport across the Hamster Jejunum

Abstract

Paired experiments were performed in vitro using two adjacent segments of hamster jejunum. Fluid and glucose transport and the intracellular concentration of glucose were compared in the intestinal segments incubated in isotonic mucosal solution (control) and in hypotonic or hypertonic mucosal solution (experimental). Hypotonic mucosal solution (212 mOsmol/kg) caused a significant increase in the serosal transfer of glucose and water, and a significant decrease in the ratio of the intracellular concentration of glucose to the concentration of glucose in the serosal fluid (T/S at the end of the experiments). Increasing the osmolality of the mucosal solution to 342, 392, and 442 mOsmol/kg caused a progressive reduction in fluid and glucose transfer to the serosal side and a progressive increase in the T/S ratio. Statistical analysis of data shows that the serosal transfer of glucose was negatively correlated with the T/S ratio and positively correlated with the serosal transfer of water. It is concluded that in the presence of a reduced solvent drag, an increased T/S ratio may not result in an increased serosal transfer of glucose.