title: Behaviour of beta 2-adrenoceptors on lymphocytes under continuous and pulsatile tocolysis with Fenoterol.
abstract: The present study investigates the population of beta 2-receptors on lymphocytes in pregnant women with premature labor between the 29th and 34th week of pregnancy. The population of receptors on lymphocytes correlates with that on the myometrium, which is not accessible for study during pregnancy. Fourteen patients received a pulsatile tocolysis, while ten women received a continuous tocolysis with Fenoterol. Assuming an equal population of receptors in both groups before commencement of therapy, the numbers of receptors in the patients with continuous tocolysis fell to about 35% of the initial value after 72 hours. Under pulsatile tocolysis, the numbers of receptors remained unchanged for a period of three days and was still only just below 70% of the initial value by the seventh day. Our data demonstrate that continuous administration of the short-acting beta 2-agonist Fenoterol resulted in a substantial loss of beta 2-adrenoceptors on lymphocytes. In contrast, intermittent administration of the same beta 2-adrenergic agonist prevented the onset of receptor down-regulation in pregnant women with preterm labor. Further studies are required to investigate the impact of the decreased loss of beta 2-adrenoceptor density on the good clinical experience with intermittent tocolysis.
authors.affiliation: Department of Gynecology and Obstetrics, Women's Hospital Barmbek-Finkenau.
authors.forename: Peter
authors.initials: P
authors.lastname: Schmidt-Rhode
authors.forename: Björn
authors.initials: B
authors.lastname: Brunke
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schröer
authors.forename: Kirstin
authors.initials: K
authors.lastname: Obert
authors.forename: Kerstin
authors.initials: K
authors.lastname: Schlegel
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sturm
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Schulz
authors.forename: Peter
authors.initials: P
authors.lastname: von Wichert
mesh_terms: D004305:Dose-Response Relationship, Drug; D005260:Female; D005280:Fenoterol / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D007752:Obstetric Labor, Premature / Q000097:blood / Q000188:drug therapy*; D011247:Pregnancy; D018343:Receptors, Adrenergic, beta-2 / Q000187:drug effects* / Q000378:metabolism; D015145:Tocolysis / Q000379:methods; D015149:Tocolytic Agents / Q000008:administration & dosage*
chemical_list: D018343:Receptors, Adrenergic, beta-2; D015149:Tocolytic Agents; D005280:Fenoterol