Abstract
The kinetics and mechanism of sn-1,2-diacylglycerol (DAG) formation induced by isoprenaline were studied in rat parotid acinar cells. DAG accumulation induced by 100 microM isoprenaline reached its maximum at 1 min, rapidly decreased (about 50%) at 5 min and then remained constant for 30 min. DAG accumulation 1 min after isoprenaline treatment was dose-dependent. Either propranolol or phentolamine inhibited isoprenaline-stimulated DAG accumulation in a dose-dependent manner. Addition of a vasoactive intestinal polypeptide, forskolin, or dibutyryl cyclic AMP had no effect on DAG accumulation. Isoprenaline did not cause the release of [3H]choline or [3H]ethanolamine metabolites into the medium. Based on the kinetics of DAG formation and [32P]phosphoinositide breakdown, we conclude that isoprenaline-induced DAG formation was mainly related to the hydrolysis of [32P]phosphatidylinositol 4,5-bisphosphate ([32P]PIP2). These results suggest that the effect of isoprenaline on DAG formation is mediated by alpha 1-adrenoceptor activation, that it is not related to the increase in cyclic AMP, and that it is closely related to PIP2 hydrolysis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
