Intestinal Growth and in Vitro Transport of Glucose in the Rapidly Growing Rat

Abstract

We examined the in vitro transport and utilization of glucose by the intestinal epithelium in rats during the period of rapid growth between 8 and 12 weeks of age. The dry weight per centimeter in length of jejunum increased in direct proportion to body weight during this interval. The absorption of glucose at the mucosal surface (per unit length of gut) did not change with growth. In contrast, the serosal secretion of glucose decreased indicating the utilization of glucose was elevated. It was further shown that the increase in glucose usage was highly correlated with the increase in intestinal dry weight that occurred during the four week interval. The data indicate the increase in intestinal tissue with growth did not result in a corresponding increase in the capacity of the intestinal epithelium to absorb glucose. We attributed the discrepancy in the transport of glucose at the mucosal and serosal surfaces to increased diversion of absorbed glucose for metabolism by intestinal tissue.