Regulation on the expression of carcino-embryonic proteins in newborn rat hepatocytes by dexamethasone. An enzyme histochemical and immunohistochemical study.

Dexamethasone (DEX) was administrated intraperitoneally to newborn rats at a dose level of 2 micrograms/g body weight/day for four days, starting 4 days after birth. After administration of DEX, large quantities of glycogen granules accumulated in the cytoplasm of hepatocytes and the activity level of gamma-glutamyl transpeptidase (gamma-GTP) in liver homogenate increased significantly, whereas that of alkaline phosphatase (ALP) exhibited no significant difference in comparison with the control group. In the histochemical analysis, after administration of DEX, a high level of activity of gamma-GTP appeared along cell borders between adjacent hepatocytes in the peripheral portion of liver lobules. On the other hand, a low level of analysis, no hepatocyte showing positive reactions to Alpha-fetoprotein (AFP) could be recognized after administration of DEX, and in livers of newborn rats receiving DEX, the number of hepatocytes which incorporated bromodeoxyuridine (BUdR) decreased. The present study showed in newborn rat that DEX induced the differentiation of hepatocytes and regulated the expression of carcino-embryonic proteins.