title: Increased affinity of histamine H1 binding to membranes of human myometrium at the end of pregnancy.
abstract: 1. The characterization of H1 binding sites in membrane preparations of human myometrium obtained from pregnant and non-pregnant women was performed by using 3H-mepyramine as the radioactive ligand. 2. Saturation curve analysis revealed that 3H-mepyramine is bound to a single class of binding sites. Changes in the H1 site binding parameters were observed at the end of pregnancy, resulting in an increased affinity relative to non-pregnant tissue (Kd: 131.0 +/- 8.8 (non-pregnant) and 72.5 +/- 7.5 (pregnant) nM, n = 6, P < 0.01). 3. A reduction in receptor concentration at the end of pregnancy was also observed, [Bmax: 565.2 +/- 43.7 (non-pregnant) and 309.6 +/- 25.9 (pregnant) fmol/mg prot, n = 6, P < 0.01]. It is possible that this reduction in Bmax could be attributed to a dilution factor due to the increase in membraneous proteins that occurs during gestation.
authors.affiliation: Departamento de Farmacología, Facultad de Ciencias Biológicas, Universidad de Concepción, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Gonzalez
authors.forename: E
authors.initials: E
authors.lastname: Echeverria
authors.forename: K
authors.initials: K
authors.lastname: Reinicke
authors.forename: M I
authors.initials: MI
authors.lastname: Rudolph
mesh_terms: D005260:Female; D006632:Histamine / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008566:Membranes / Q000378:metabolism; D009215:Myometrium / Q000378:metabolism*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000378:metabolism*; D011869:Radioligand Assay; D011969:Receptors, Histamine H1 / Q000378:metabolism*
chemical_list: D011969:Receptors, Histamine H1; D006632:Histamine