エンドセリン-1 によるエールリッヒ腹水癌細胞からのリポタンパク質リパーゼの分泌(発表論文抄録(2010))

Since the role of endothelin (ET)-1 in lipoprotein metabolism in tumor cells is unclear, we investigated the effect of ET-1 on the secretion of lipoprotein lipase (LPL) from mouse Ehrlich ascites tumor cells. ET-1 increased the secretion of LPL from these cells in a time-dependent manner. Two antagonists of ET-receptor type A (ET-A), namely, BQ123 and FR139317, inhibited the stimulatory effect of ET-1 on the secretion of LPL. However, an antagonist of ET-receptor type B (ET-B), BQ788, did not have any effect. Neomycin, a phospholipase C (PLC) inhibitor, and H-7, a protein kinase C (PKC) inhibitor, also suppressed the ET-1-stimulated secretion of LPL. ET-1 also increased PKC activity in tumor cells in a dose-dependent manner. These results imply that ET-1 stimulates secretion of LPL from tumor cells by stimulating the PLC-PKC signaling pathway through the ET-A receptor rather than the ET-B receptor.Since the role of endothelin (ET)-1 in lipoprotein metabolism in tumor cells is unclear, we investigated the effect of ET-1 on the secretion of lipoprotein lipase (LPL) from mouse Ehrlich ascites tumor cells. ET-1 increased the secretion of LPL from these cells in a time-dependent manner. Two antagonists of ET-receptor type A (ET-A), namely, BQ123 and FR139317, inhibited the stimulatory effect of ET-1 on the secretion of LPL. However, an antagonist of ET-receptor type B (ET-B), BQ788, did not have any effect. Neomycin, a phospholipase C (PLC) inhibitor, and H-7, a protein kinase C (PKC) inhibitor, also suppressed the ET-1-stimulated secretion of LPL. ET-1 also increased PKC activity in tumor cells in a dose-dependent manner. These results imply that ET-1 stimulates secretion of LPL from tumor cells by stimulating the PLC-PKC signaling pathway through the ET-A receptor rather than the ET-B receptor

プラゾシンによる初代培養ラット肝細胞からの肝性リパーゼの分泌促進(発表論文抄録(2010))

Prazosin is an alpha 1 adrenoceptor antagonist, and it is used as an antihypertensive agent. The effects of prazosin on the activity of hepatic triacylglycerole lipase (HTGL) are not fully understood. In this study, we demonstrated that prazosin stimulates the release of HTGL activity from primary cultures of rat hepatocytes in a time- and dose-dependent manner. U-73122, a phopholipase C (PLC) inhibitor, suppresses prazosin\u27s stimulation of the release of HTGL activity. Moreover, prazosin stimulated the increase of PLC activity in the hepatocytes in a time- and dose-dependent manner. In addition, the prazosin-stimulated release of HTGL activity was reduced by Quin2/AM (an intracellular Ca2+-chelator), W-7 (a Calmodulin inhibitor), and KN-93 [an inhibitor of Ca2+/Calmodulin dependent protein kinase (CaMK)-II]. These results suggest that the prazosin-stimulated release of HTGL activity is partly due to the activation of CaMK-II that is associated with the elevation of PLC activity in the hepatocytes.Prazosin is an alpha 1 adrenoceptor antagonist, and it is used as an antihypertensive agent. The effects of prazosin on the activity of hepatic triacylglycerole lipase (HTGL) are not fully understood. In this study, we demonstrated that prazosin stimulates the release of HTGL activity from primary cultures of rat hepatocytes in a time- and dose-dependent manner. U-73122, a phopholipase C (PLC) inhibitor, suppresses prazosin\u27s stimulation of the release of HTGL activity. Moreover, prazosin stimulated the increase of PLC activity in the hepatocytes in a time- and dose-dependent manner. In addition, the prazosin-stimulated release of HTGL activity was reduced by Quin2/AM (an intracellular Ca2+-chelator), W-7 (a Calmodulin inhibitor), and KN-93 [an inhibitor of Ca2+/Calmodulin dependent protein kinase (CaMK)-II]. These results suggest that the prazosin-stimulated release of HTGL activity is partly due to the activation of CaMK-II that is associated with the elevation of PLC activity in the hepatocytes