Promoting effect of estrogen on regeneration of the liver transplanted to an ectopic site in mice.

A single oral administration of a pharmacological dose of estriol (E3) immediately after transplantation of small liver fragments of mice under the kidney capsule induced a remarkable growth of regenerating liver tissue. The hepatocytes were successfully arranged in cords with well developed sinusoids between them. The cytoplasm of the hepatocytes showed prominent basophilia. In mice injected with carbon intravenously, large numbers of carbon-laden endothelial lining cells and Kupffer cells appeared in the newly building sinusoids. E3 raised the mitotic activity of the regenerating hepatocytes markedly and for a long period. The act of E3 on mitosis was much more effective on the regenerating hepatocytes than on the recipient's own hepatocytes.