title: Regulation of [3H]forskolin binding to human platelet membranes by GppNHp, NaF, and prostaglandin E1.
abstract: Displaceable binding of [3H]forskolin to human platelet membranes can be detected in the presence of magnesium. There is an increase in the number of [3H]forskolin binding sites when membranes are incubated with GppNHp or NaF in the presence of magnesium. Prostaglandin E1, which stimulates human platelet adenylate cyclase, does not affect the binding of [3H]forskolin in the absence of GppNHp. However, the dose-response curve for the GppNHp-dependent increase in [3H]forskolin binding sites is shifted to lower concentrations in the presence of prostaglandin E1. Prostaglandin E1 potentiates the effect of GppNHp on [3H]forskolin binding most likely by facilitating the binding of the guanine nucleotide at the stimulatory quanine nucleotide regulatory protein of adenylate cyclase.
mesh_terms: D000527:Alprostadil; D001665:Binding Sites; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005576:Colforsin; D004224:Diterpenes / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D011458:Prostaglandins E / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: D004224:Diterpenes; D011458:Prostaglandins E; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D000527:Alprostadil