title: Human myometrial adrenergic receptors during pregnancy: identification of the alpha-adrenergic receptor by [3H] dihydroergocryptine binding.
abstract: The radioactive alpha-adrenergic antagonist [3H] dihydroergocryptine binds to particulate preparations of term pregnant human myometrium in a manner compatible with binding to the alpha-adrenergic receptor (alpha-receptor). [3H] Dihydroergocryptine binds with high affinity (KD = 2 nmol/L and low capacity (receptor concentration = 100 fmol/mg of protein). Adrenergic agonists compete for [3H] dihydroergocryptine binding sites stereo-selectively ([-]-norepinephrine is 100 times as potent as [+]-norepinephrine) and in a manner compatible with alpha-adrenergic potencies (epinephrine approximately equal to norepinephrine much greater than isoproterenol). Studies in which prazosin, an alpha 1-antagonist, and yohimbine, and alpha 2-antagonist, competed for [3H] dihydroergocryptine binding sites in human myometrium indicated that approximately 70% are alpha 2-receptors and that 30% are alpha 1-receptors. [3H] dihydroergocryptine binding to human myometrial membrane particulate provides an important tool with which to study the molecular mechanisms of uterine alpha-adrenergic response.
authors.forename: M M
authors.initials: MM
authors.lastname: Jacobs
authors.forename: D
authors.initials: D
authors.lastname: Hayashida
authors.forename: J M
authors.initials: JM
authors.lastname: Roberts
mesh_terms: D004088:Dihydroergotoxine / Q000378:metabolism*; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D009215:Myometrium / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011247:Pregnancy; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D014316:Tritium; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D011942:Receptors, Adrenergic, alpha; D014316:Tritium; D004088:Dihydroergotoxine; D015016:Yohimbine; D007545:Isoproterenol; D009638:Norepinephrine; D011224:Prazosin; D004837:Epinephrine; D010646:Phentolamine