Effects of Blood Glucose and Plasma Osmolality on Transmucosal Fluid Movement and Intestinal Drug Absorption

It had been clarified in our previous study that the transmucosal fluid inflow and the absorption of sulfanilamide in alloxan diabetic rats were increased significantly than in control rats using the in situ recirculating perfusion method. The present study was designed to elucidate further in full the effects of diabetes on these intestinal absorptions. Plasma osmolality was increased with increasing blood glucose and a good correlation was obtained over a wide range of the blood glucose. The increase of blood glucose resulted in the increment of the transmucosal fluid inflow and the absorption of the drug. To examine these effects of blood glucose, rats having hyperglycemia, one of physiological characteristics in diabetic animals, were prepared by the administration of D-glucose. The fluid movement and the drug absorption in the glucose administered rats were significantly increased than in the controls and were not found significant difference compared to those of the diabetics on the basis of dry-weight of the small intestine of the experimental animal. From the results obtained in the present study and in our previous findings, it might be able to conclude that a possible mechanism on the increase of the drug absorption in the diabetics would be that the enhancement of plasma osmolality due to the hyperglycemia caused the increment of the transmucosal fluid inflow to compensate the abnormal high osmolality in blood and this inflow might lead the drug absorption increase consequently.