The influence of biologically active substances on the regenerative processes of enterocytes in the small intestine of the rat.

The influence of a prolonged treatment with procaine or Turigeran on the cell population kinetics of the mucous membrane of the small intestine was studied by means of 3H-thymidine histoautoradiography in 240 12-month-old male Wistar rats. The investigations produced the following findings: 1. There are no differences in the cell population kinetics of the mucous membrane of the small intestine between procaine- and Turigeran-treated animals. But as, on the other hand, significant differences are found between treated and untreated animals in terms of all cell-kinetic characteristics, this effect has to be attributed to procaine alone. 2. In treated animals the partial stages of the cell cycle are prolonged as a result of which the generation time is delayed. 3. Due to the fact that the transit time of the cells in the crypts and on the villi is reduced, a greater number of labelled cells can finally be observed despite reduced proliferation rates in the crypts (labelling index) of treated animals. 4. Procaine will continue to act with undiminished effectiveness for at least two weeks after discontinuation of treatment.