MORPHOLOGICAL AND AUTORADIOGRAPHIC INVESTIGATION OF ALTERATIONS OF INTESTINAL MUCOSA AFTER A SINGLE INJECTION OF 1,2-DIMETHYLHYDRAZINE

In the present study using 61 female NMRI-mice (including controls) and with application of3H-thymidine-autoradiography the following results were found after a single subcutaneous injection of 1,2-dimethylhydrazine: A single subcutaneous injection of 14 mg/kg causes a clearly detectable cytotoxic damage of the epithelial mucosa cells in the crypts of Lieberkühn in small and large intestine as well as a disturbance of their normal proliferation kinetics. A prevalent damaging in a certain phase of the regeneration cycle of the cells cannot be derived. A prolongation of the DNA-synthesis-phase is possible. The number of damaged cells (pyknoses) reaches a maximum 8-24 h after 1,2-dimethylhydrazine-injection. At the same time the total number of epithelial crypt cells is considerably diminished and the emigration of differentiated cells from the crypts is reduced in consequence. The cytotoxic effect of 1,2-dimethylhydrazine and the following reparative reaction of the regenerative population last longer in large intestine. It is referred to parallels and differences in the effects on mucosa and proliferation kinetics between the alkylating 1,2-dimethylhydrazine and a folic acid antagonist (Methotrexate). © 1969 Springer-Verlag.