EXPRESSION AND CELLULAR LOCATION OF ENDOTHELIN-1 MESSENGER-RNA IN RAT-LIVER FOLLOWING ENDOTOXEMIA

Objective To study the effect of endotoxin on the alteration of the tr anscription, expression and cellular location of endothelin-1 (ET-1) m RNA in the hepatic tissue. Methods Wistar rats were divided into contr ol and endotoxic group. The rats in the control group were injected wi th saline, and those in the endotoxic group with endotoxin at a dose o f 10 mg.kg(-1) body wt. ET-1 hepatic homogenate was assayed by radioim munoassay 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, 1 2 and 24 h after endotoxin administration. Results 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 s itu hybridization, ET-1 mRNA was found in hepatic sinusoids, endotheli al cells of portal vein and kupffer cells. Conclusions Endotoxin may b e the principal stimulating factor for expression of ET-1 mRNA in hepa tic tissue. Endotoxin may affect transcription and translation level o f ET-1, leading to increase of the synthesis and release of ET-1. The hepatic vascular endothelial cells, hepatic sinusoids and Kupffer cell s all synthesize and release ET-1.