Suppressive effects of the endothelin receptor (ETA) antagonist BQ-123 on ET-1-induced reduction of lipoprotein lipase activity in 3T3-L1 adipocytes

Abstract Endothelin (ET)-l reduced heparin-releasable lipoprotein lipase (LPL) activity in 3T3-L1 adipocytes in a concentration-dependent manner. However, a selective ET B receptor agonist, [Ala 1.3.11.15 ]ET-l, did not act like ET-1. The ET-1-induced decrease in LPL activity was suppressed by a selective ET A receptor antagonist, BO-123: the concentration-response curve for the ET-1 reduction of LPL activity was shifted to the right in the presence of BQ-123 in a concentration-dependent manner. This antagonistic effect of BQ-123 clarifies that the ET A receptor is responsible for the ET-1-induced reduction of LPL activity in 3T3-L1 adipocytes, which suggests that there is therapeutic potential for ET A antagonists in LPL-related lipoprotein disorders.