[Endocrine intestinal low molecular weight factor inhibits Na+,K+- ATPase activity of enterocytes]

The biological activity of the endocrine secretum fraction isolated from the rat duodenum is determined. The fraction with the molecular weight about 3 kDa is found to possess the factor which inhibits the Na+,K+-ATPase activity of enterocytes. It is found that the inhibitory factor secretum depends on the solution which irrigates the duodenum cavity. The possible regulatory role of the intestine inhibitory factor is under discussion.