G2 POPULATION CELLS IN MOUSE DUODENUM

In this work the effect of the injection of a) liver extract or plasma from intact mice and b) ES2 malignant tumor extract or plasma from tu mor bearing animals on the duodenal crypt population cells blocked in G2 are analyzed. Eighty-nine C3HS male mice (25 +/- 2 days old) standa rdized for periodicity analysis were injected intraperitoneally at 16: 00 hours in doses of 0.01 ml per gram of body weight. They were sacrif iced at 20:00, 00:00 and 04:00 hours, after an intraperitoneal injecti on of 2 ug of colchicine per gram of body weight, The duodenum was pro cessed for histology. The mitotic activity was expressed as colchicine metaphases per 1000 nuclei of the stem cells, transit cells and diffe rentiated cells. The results were analyzed with the Student ''t test'' . We found that tumor extract and plasma from the tumor bearing mice s timulated the G2 arrested transit cells to mitosis. The liver extract and the plasma from the intact mice had no effect on the G2 duodenum p opulation cells, thereby the tumor extract and the plasma from the tum or bearing animals would be specific triggers of G2 transit cells popu lation.