Morphologic study on Ito cell (Fat-storing cell) contractility

点击翻译按钮获取中文摘要

We studied for the hepatic Ito cells (Fat-storing cell) contractility.1. Binding sites of ^<125>I-endothelin-1 (ET-1) and ^<125>I-substance P (SP) in the human or rat liver, which are vasoconstractive agents, were examined by light and electron microscopic auto-radiography. At the light microscopic level, a remarkable accumulation of ^<125>I-ET-1 and ^<125>I-SP grains was observed in areas which appear to be the perisinusoidal spaces. At the electron microscopic level, these grains were detected on the plasma membrane of Ito cells compared with other hepatic cells. These findings suggest that the receptors of ET-1 and SP may be present in the cells.2. Immunolocalization of actin, myosin and calmodulin in the human Ito cells was examined by immunoperoxidase methods using anti-actin, myosin and calmodulin antibodies. Immunolocalization of actin, myosin and calmodulin was observed in the cytoplasm of Ito cells. These findings suggest that Ito cells may have the contractility.3. The area of Ito cells was measured after treatment with ET-1 or SP at various concentrations in the culture medium. The area of the cells was decreased dose-dependently after treatment with ET-1 or SP. The mode of the extent and onset of the contraction was different for the two peptides. These findings suggest that Ito cells may be involved in regulation of the hepatic sinusoidal microcirculation.4. Immunolocalization of ET-1 was observed in cultured sinusoidal endothelia.5. ET-1 concentration in portal and peripheral veins was measured in patients with non-liver disease and liver cirrhosis. ET-1 concentration of these veins was higher in patients with cirrhosis than in patients with non-liver disease. The finding suggests ET-1 may be involved in the hepatic sinusoidal microcirculation.