title: Effect of fluoride on the phosphodiesterase of bovine photoreceptors.
abstract: In the absence of the specific hormone, fluoride is able to activate the adenylate cyclase because it interacts with the GTP-binding protein. It has been reported that fluoride activates also the phosphodiesterase of the light-sensitive enzymatic cascade in dark-adapted retinal rod outer segments, but there is no indication that the GTP-binding protein is involved in this process or not. We show here that also in the photoreceptor system fluoride does interact with the GTP-binding protein in order to activate the phosphodiesterase in the dark. Further, we show evidences that fluoride solubilizes the GTP-binding protein in the dark and that the resulting complex activates the phosphodiesterase in dark-adapted rod outer segment membranes.
mesh_terms: D000818:Animals; D002417:Cattle; D003623:Dark Adaptation; D004591:Electrophoresis, Polyacrylamide Gel; D005459:Fluorides / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010786:Photoreceptor Cells / Q000201:enzymology*; D012374:Rod Cell Outer Segment / Q000187:drug effects / Q000201:enzymology*
chemical_list: D010727:Phosphoric Diester Hydrolases; D019204:GTP-Binding Proteins; D005459:Fluorides