Expression and cellular location of endothelin-1 mRNA in rat liver following endotoxemia

To study the effect of endotoxin on the alteration of the transcription, expression and cellular location of endothelin-1 (ET-1) mRNA in the hepatic tissue.

Wistar rats were divided into control and endotoxic group. The rats in the control group were injected with saline, and those in the endotoxic group with endotoxin at a dose of 10 mg.kg-1 body wt. ET-1 hepatic homogenate was assayed by radioimmunoassay at 3, 6, 9, 12 and 24 h after endotoxin administration. Dot blot was used to identify and quantify ET-1 mRNA of the hepatic tissue. Hybridization of ET-1 of the hepatic tissue was proceeded at 3, 6, 12 and 24 h after endotoxin administration.

ET-1 concentrations and the level of ET-1 mRNA increased rapidly and reached the peak at 6 h, and remained high at 24 h after endotoxin administration. By in situ hybridization, ET-1 mRNA was found in hepatic sinusoids, endothelial cells of portal vein and kupffer cells.

Endotoxin may be the principal stimulating factor for expression of ET-1 mRNA in hepatic tissue. Endotoxin may affect transcription and translation level of ET-1, leading to increase of the synthesis and release of ET-1. The hepatic vascular endothelial cells, hepatic sinusoids and Kupffer cells all synthesize and release ET-1.