title: Extragonadal LH/hCG action--not yet time to rewrite textbooks.
abstract: Gonadotropins are indispensable in both sexes in the regulation of gonadal sex steroid production and gametogenesis. In addition to their well-established classical actions, numerous recent publications have indicated the presence and function of luteinizing hormone/chorionic gonadotropin receptors (LH/hCG-R) in a variety of extragonadal tissues. However, the physiological significance of such effects has remained unclear. We have generated two genetically modified mouse models, one with excessive production of hCG and the other with targeted disruption of LH/hCG-R gene, and used them to address the functions of LH and hCG. Numerous gonadal and extragonadal phenotypes were found in the models with the two extremes of LH/hCG action. However, when the extragonadal effects were scrutinized in greater detail, they all appeared to arise through modification of gonadal function, either through enhanced or inhibited response to LH/hCG stimulation. Hence, further evidence is needed before the extragonadal LH/hCG-R expression can be considered functionally significant.
authors.affiliation: Department of Physiology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Tomi
authors.initials: T
authors.lastname: Pakarainen
authors.forename: Petteri
authors.initials: P
authors.lastname: Ahtiainen
authors.forename: Fu-Ping
authors.initials: FP
authors.lastname: Zhang
authors.forename: Susana
authors.initials: S
authors.lastname: Rulli
authors.forename: Matti
authors.initials: M
authors.lastname: Poutanen
authors.forename: Ilpo
authors.initials: I
authors.lastname: Huhtaniemi
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects; D005260:Female; D006062:Gonadotropins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D006066:Gonads / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D010053:Ovary / Q000637:transplantation
chemical_list: D006062:Gonadotropins