Abstract
By horizontal sectioning of a fresh frozen piece of rat intestinal wall different parts of the villi and the crypts were isolated. Every third serial section was taken for histologic examination and the intermediate sections were combined in pairs, homogenized and used for enzyme analysis. A quantitative comparison of the distribution of alkaline phosphatase, EC 3.1.3.1, disaccharidase, EC 3.2.1 (maltase, invertase, isomaltase, trehalase, lactase and cellobiase), and dipeptidase, EC 3.4.3 (L-alanyl-L-proline dipeptidase, L-alanyl-L-glutamic acid dipeptidase and glycyl-L-leucine dipeptidase), activities was performed. All of the enzymes were present in the villi and absent from the crypts. The disaccharidase and dipeptidase activities showed a rather similar distribution. The highest activities were found in the apical halves of the villi. The alkaline phosphatase activity was more distinctly located in the tips of the villi.