title: Gonadotropin and free alpha-subunit secretion in patients during GnRH-agonist treatment.
abstract: In female patients gonadotropin and free alpha-subunit serum levels during GnRH-agonist (GnRH-a) treatment were investigated. Using two different immunoassays (RIA, IRMA) as well as LH in-vitro bioassay evidence was found for pituitary secretion of incomplete LH molecular forms which are detected false positive in RIA measurements but neither in IRMA nor in bioassay. In the GnRH-a induced desensitization state suppression of LH serum levels was more profound as compared to FSH. In contrast to gonadotropins free alpha-subunit serum levels were shown to increase in a biphasic course leading to ninefold higher levels persisting during GnRH-a treatment. A further increase was achieved by exogenous GnRH but not by estradiol. In conclusion these in-vivo data give evidence for a gradually different suppression of gonadotropic secretion by the use of GnRH-a. The mechanisms of inhibition are discussed to be directed to steps in the processing of beta-subunit synthesis but not of alpha-subunit.
authors.affiliation: Abteilung für klinische und experimentelle Endokrinologie, Zentrum für Reproduktionsmedizin, Universitäts-Frauenklinik Hamburg-Eppendorf, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lindner
authors.forename: V
authors.initials: V
authors.lastname: Lichtenberg
authors.forename: W
authors.initials: W
authors.lastname: Braendle
mesh_terms: D000328:Adult; D002849:Chromatography, Gas; D003692:Delayed-Action Preparations; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology*; D006062:Gonadotropins / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008186:Luteolytic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D046911:Macromolecular Substances; D011446:Prospective Studies; D011863:Radioimmunoassay; D013997:Time Factors; D017329:Triptorelin Pamoate
chemical_list: D003692:Delayed-Action Preparations; D006062:Gonadotropins; D008186:Luteolytic Agents; D046911:Macromolecular Substances; D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone