title: Pretreatment with 17 beta-estradiol attenuates basal- and PTH-stimulated membrane adenylyl cyclase activity in human osteoblast-like SAOS-2 cells.
abstract: Parathyroid hormone (PTH)-stimulated production of cAMP by intact human osteoblast-like SaOS-2 cells is diminished by pretreatment with 17 beta-estradiol (E2). The goal of the present study was to determine whether E2, affected adenylyl cyclase activity in cell membranes. Cells were deprived of steroid hormones for 24 h and then incubated with E2 (1 nM) or vehicle for 12 h. Cell membranes were prepared and incubated with [alpha-32P]-ATP in the absence or presence of agonist, and the amount of [32P]-cAMP produced was measured to quantify adenylyl cyclase activity. There was less cAMP produced by membranes from E2-treated cells in response to PTH, GTP gamma S, forskolin, and Mn2+. E2 had no effect on the amounts of Gs or Gi. We propose that pretreatment of SaOS-2 cells with E2 reduced membrane cyclase activity, at least in part, by actions on the PTH-sensitive adenylyl cyclase and/or the G protein-adenylyl cyclase complex.
authors.affiliation: Department of Molecular and Cellular Toxicology, Harvard School of Public Health, Boston Massachusetts, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Monroe
authors.forename: A H
authors.initials: AH
authors.lastname: Tashjian
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D010006:Osteoblasts / Q000201:enzymology*; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology; D010761:Phosphorus Radioisotopes; D019379:Teriparatide; D013997:Time Factors
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; D010761:Phosphorus Radioisotopes; D019379:Teriparatide; D005576:Colforsin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D008345:Manganese; D004958:Estradiol; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D000262:Adenylyl Cyclases