Intestinal absorption of hypertonic solutions of glucose and its influence on the capacity of absorption

Abstract

The intestinal absorption of hypertonic glucose Solutions has been systematically studied. With the Sois and Tonz method each concentration has been tested in four succesive periods of 30 minutes in rats. It has been found that whereas with isotonic glucose solu­tions absorption is constant in the four succesive periods, the absorp­tion from hypertonic solutions progressively decrcased with time. This decrease was apparent at 10.8, greater at 16.2, and much greater at 21.6 percent concentration. In any case, in the first 30 minutes period absorption was greater the greater the concentration. But in subsequent periods the relation concentration/absorption was different, and eveii a partial inversion occurred in the last periods.

Histological examinaron after absorption of hypertonic glucose Solutions showed alterations of the intestinal mucosa Again the intensity of epithelial damage was proportional to the degree of hypertonicity and time. After absorptiou of isotonic solutions oedema and infiltraron in the submucosa were observed, but no damage of the epithelium.
The histological picture of the small intestine, as well as that of the stomach, has also been investigated 1 to 5 hours after intragastric administraron of 2 cc. of 50 percent glucose to rats as in Cori method. Epithelial damage of the same kind as that found in the isolated loops was observed in the duodenum and jcjunum, but not in the stomach.

It is concluded that whenever hypertonic Solutions have been used for studies of intestinal absorption, damage of the intestinal mucosa must have affected the results, tó some exteht even following intragastric administraron. In isolated loops of intestine the progresive uecrease in capacity of absorption affects the relation between con­ centraron and rate of absorption to such and extent that results depend on the duration of the experiments. The concentation which produces maximal absorption vanes with time. And at a particular time it may appear — as in fact has been affirmed some time ago — that absorption of glucose is independent of the concentration.