EFFECTS OF ESTROGEN ON MOUSE LIVER SINUSOIDAL CELLS

The effects of estrogen on liver sinusoidal cells were investigated immunohistochemically and morphometrically. Male AKR/n mice were orally administered 30mg/kg/day of mestranol suspended in sesame oil for 7 days. Some of the mice were splenectomized before mestranol administration. Relative liver weight significantly increased from day l to day 7 in mestranol-administered mice with or without spleen. Relative spleen weight also significantly increased from day 3 to day 5 in these mice. Histologically, cellular increase was observed in both the sinusoid of the liver and the red pulp of the spleen. Almost all cells that increased in the sinusoid of the liver were positive for F4/80, and cells positive for PCNA also increased. These changes were observed in mestranol-administered mice with or without spleen. In the morphometrical study, the peak number of F4/80 positive cells in the liver was observed from day 5 and day 7 in normal and splenectomized mice administered mentranol, respectively. On day 5 and day 7, the number of F4/80 positive cells observed in the mestranol-administered splenectomized mice was significantly higher than that in mestranol-administered normal mice. The peak number of PCNA positive cells in the liver was observed on day 3 in mestranol-administered splenectomized mice, and on day 5 in mestranol-administered normal mice. The number of PCNA positive cells was significantly higher on day 3 in splenectomized rather than normal mice administered mestranol. These results suggest that the liver disturbances observed in women taking estrogen for a long time may be closely related to local proliferation of Kupffer cells in the sinusoid.