[Action of liver extract from partially hepatectomized mice on the mitotic activity of young mouse enterocytes].

We have previously demonstrated that adult mouse plasma obtained 36 hours post partial hepatectomy has an inhibitory effect on the mitotic activity of enterocytes from young mouse duodenal cripts. In this paper we investigate whether this effect is derived from any regenerating liver factor. Accordingly, we studied the action of adult mouse (90 days old) liver extract obtained 36 hours after partial hepatectomy (70%), on the mitotic activity of young mouse enterocytes, considering 3 cellular levels of the duodenum cripts. Thirty six C3H/S inbred female mice (27 days old) were employed. Half of them received at 16:00 hour an intraperitoneal injection of saline and the other half received liver extract (0.01 ml/g). Animals from each group were sacrificed at 08:00/ 16, 12:00/20 and 16:00/24 (time of day/hours post treatment). All the animals received an intraperitoneal dose of colchicine (2 micrograms/g) 4 hours before sacrifice. The results are expressed as colchicine metaphases/1000 nuclei and show that the mitotic activity is significantly lower in the animals treated with the extract than in the controls. This inhibiting effect is observed at the levels from 1 to 4 and from 5 to 12 cells of the analyzed cripts. At the superficial level from 13 to 20 cells there is no modification of the proliferative activity. This inhibiting effect on the mitotic activity of duodenum enterocytes from the basal and intermedial zone of the cripts is probably due to a liver diffusing factor.