title: Inositol polyphosphate production and regulation of cytosolic calcium during the biphasic activation of adrenal glomerulosa cells by angiotensin II.
abstract: Stimulation of aldosterone production by angiotensin II in the adrenal glomerulosa cell is mediated by increased phosphoinositide turnover and elevation of intracellular Ca2+ concentration. In cultured bovine glomerulosa cells, angiotensin II caused rapid increases in inositol-1,4,5-trisphosphate (Ins-1,4,5-P3) levels and cytosolic Ca2+ during the first minute of stimulation, when both responses peaked between 5 and 10 s and subsequently declined to above-baseline levels. In addition to this temporal correlation, the dose-response relationships of the angiotensin-induced peak increases in cytosolic Ca2+ concentrations and Ins-1,4,5-P3 levels measured at 10 s were closely similar. However, at later times (greater than 1 min) there was a secondary elevation of Ins-1,4,5-P3, paralleled by increased formation of inositol 1,3,4,5-tetrakisphosphate that was associated with cytosolic Ca2+ concentrations only slightly above the resting value. These results are consistent with the primary role of Ins-1,4,5-P3 in calcium mobilization during activation of the glomerulosa cell by angiotensin II. They also suggest that Ins-1,4,5-P3 participates in the later phase of the target-cell response, possibly by acting alone or in conjunction with its phosphorylated metabolites to promote calcium entry and elevation of cytosolic Ca2+ during the sustained phase of aldosterone secretion.
authors.affiliation: Endocrinology and Reproduction Research Branch, NICHD, Bethesda, Maryland 20892.
authors.forename: T
authors.initials: T
authors.lastname: Balla
authors.forename: W P
authors.initials: WP
authors.lastname: Hausdorff
authors.forename: A J
authors.initials: AJ
authors.lastname: Baukal
authors.forename: K J
authors.initials: KJ
authors.lastname: Catt
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001711:Biotransformation / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D007295:Inositol Phosphates / Q000096:biosynthesis*; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D013403:Sugar Phosphates / Q000096:biosynthesis*; D015384:Zona Glomerulosa / Q000187:drug effects / Q000378:metabolism*
chemical_list: D007295:Inositol Phosphates; D013403:Sugar Phosphates; D000804:Angiotensin II; D002118:Calcium