title: 1-Acetyl-7-deacetylforskolin: a potential non-specific inactive analog of forskolin for estimation of its specific high-affinity binding and adenylyl cyclase stimulation in vitro.
abstract: Labeled and unlabeled 1-acetyl-7-deacetylforskolin and forskolin were synthesized by acetylation of 7-deacetylforskolin with labeled and unlabeled acetyl chloride. The binding of 1-acetyl[1-acetyl-11C]-7-deacetylforskolin ([11C]1-acetyl-7-deacetylforskolin) and [7-acetyl-11C]forskolin ([11C]forskolin) to rat brain membranes was studied using filtration assay. The [11C]forskolin binding was decreased with an increasing load of unlabeled forskolin, whereas [11C]1-acetyl-7-deacetyl-forskolin binding was always very low, the level of which agreed with that of the non-specific binding in forskolin. However, binding of [7-acetyl-11C]1,9-dideoxyforskolin, which has been used as a non-specific inactive analog of forskolin, had a higher binding ratio than that of the non-specific binding of forskolin. The binding of [11C]forskolin was not affected by an increased load of cold 1-acetyl-7-deacetylforskolin. Forskolin activated adenylyl cyclase (AC) in cultured human endothelial cells, whereas 1-acetyl-7-deacetylforskolin did not. These data show that the 1-acetyl-7-deacetylforskolin lacks specific binding affinity and the ability to stimulate AC, while it has similar physical properties with forskolin. The compound 1-acetyl-7-deacetylforskolin would be a suitable "non-specific inactive analog" of forskolin with which to estimate its specific high-affinity binding capacity and to validate forskolin-specific AC stimulation in vitro.
authors.affiliation: Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Furukata
authors.forename: T
authors.initials: T
authors.lastname: Iimori
authors.forename: S
authors.initials: S
authors.lastname: Ikegami
authors.forename: S
authors.initials: S
authors.lastname: Ide
authors.forename: T
authors.initials: T
authors.lastname: Hosokami
authors.forename: M
authors.initials: M
authors.lastname: Senda
mesh_terms: D000262:Adenylyl Cyclases / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005576:Colforsin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D066298:In Vitro Techniques; D016548:Prosencephalon / Q000378:metabolism; D051381:Rats; D014471:Umbilical Veins
chemical_list: C095702:1-acetyl-7-deacetylforskolin; D005576:Colforsin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; C047983:1,9-dideoxyforskolin