RESUMO
The aims of this study were to characterize the endothelin (ET) system in human gallbladder by determining (1) the tissue content of ET-1 and ET-2 by ELISA; (2) the expression of mRNA of the ET precursors preproendothelin-1, -2, and -3; and (3) mRNA expression for the ETA and ETB receptors. Median content of ET-1/2 was significantly reduced in severely inflamed gallbladders compared to gallbladders with mild inflammation. There was an inverse correlation between content of ET-1/2 and inflammation score. mRNA for preproendothelin-2 was highly expressed in all samples, whereas mRNA for preproendothelin-1 was present in negligible quantities and mRNA for preproendothelin-3 was undetectable. mRNA for ETA receptors was expressed in all samples analyzed, whereas mRNA for ETB receptors was expressed at a much lower level. This study demonstrates the presence of ET-1/2 in human gallbladder. ET-1/2 content is decreased with increasing degrees of histological inflammation. ET-2 is likely to be the physiologically significant endothelin isopeptide expressed and ETA receptors appear to predominate in the human gallbladder.
