title: Beta-adrenergic receptors in early human placenta characterization of [3H]-dihydroalprenolol binding.
abstract: The binding characteristics of beta-adrenergic ligand [3H]-dihydroalprenolol (DHA) were determined in particulate membranes of early human placenta (8-12 weeks of gestation). [3H]-DHA binding to crude membrane fractions was rapid, reversible, saturable and linearly correlated with the membrane protein concentration. Scatchard analysis of saturation experiments showed a KD of 2.80 +/- 0.9 nM and a density of binding sites of 330.30 +/- 93.5 fmol/mg protein. Agonist potency isoproterenol greater than epinephrine greater than norepinephrine indicated that early human placenta contains an adrenergic receptor of beta-2 subtype.
mesh_terms: D000526:Alprenolol / Q000031:analogs & derivatives*; D001667:Binding, Competitive; D004082:Dihydroalprenolol / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000378:metabolism; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D000526:Alprenolol; D007545:Isoproterenol; D009638:Norepinephrine; D004837:Epinephrine