On the Regenerative Process of the Hepatic Parenchymal Cells in Parabiotic Rats.

In order to investigate on humoral factors concerning regeneration and proliferation of cells, histological, histochemical and micrometrical observations were made on livers of successful parabiotic rats, at intervals during regenerative course of one of the partners which had been partially hepatectomized. Changing pattern in size of hepatic cells was very similar between hepatectomized and non-hepatectomized partners. A considerable increase in number of mitotic figures and binucleate cells as well as in nuclear size, and some histochemical findings which were closely related to mitotic activity were observed only in the hepatectomized partner, as seen in partially hepatectomized single rats. In con<;lusion, the compensatory h yperfunction of hepatic cells was evidenced in the non-hepat ectomized partner after partial hepatectomy of the other, a nd therefore a n exchange of humora l factor concerning stimulation of hepatic function was substantiated. While, the experiment yielded a negative result for the exchange of mitotic stimulating factor.