The Adenosine Triphosphate Contents of the Mucosa and the Entire Wall of the Alimentary Tract of the Rat and the Activities of the Enzyme System Hydrolyzing ATP in the Alimentary Tract Mucosa of the Rat During the Absorption of Nutrients.

Abstract

The contents of adenosine triphosphate (ATP) in the mucosae and walls in different parts of the alimentary tract and the activities of the enzyme system hydrolyzing ATP in mucosa homogenates have been determined. The contents in the liver and, in some cases, also in the abdominal rectus muscle were determined for comparison. The liver was found to contain 1.80[long dash]4.17 [mu]moles of ATP/g of dry weight (19.1[long dash]56.3 [mu]moles of ATP/g of ammonia-N) in different series of experiments. The membranous part of the stomach wall contained slightly more than 1/3 of the amount of ATP in the mucosa of the oral part of the small intestine. The glandular stomach mucosa contained about the same amount of the compound as the oral end of the small intestine, where the content was 1.05 [mu]moles of ATP/g of dry weight (9.93 [mu]moles/g of ammonia N). Samples of the entire wall from the 1st 5 cm of the small intestine contained 4.85 [mu]moles of ATP/g of dry weight (49.7 [mu]moles/g of ammonia N). Further along the small intestine the content of ATP decreased both in the mucosa and in the entire wall. This decrease was not linear, but clearly more rapid in the oral than in the aboral part of the intestine. In the investigations the ATP content of the appendix was of the same order as the content in the lower end of the small intestine and the ATP content of the entire wall of the large intestine was nearly equal to the contents in the upper end of the small intestine. The activity of the enzyme system in the liver was about 1/2 of the activity in the initial part of the small intestine. The enzyme activity in the stomach was about 1/5 of that in the initial part of the small intestine; the enzyme activity decreased in a non-linear manner along the small intestine. The activity in the appendix and the large intestine was at the same level as in the lower end of the small intestine.