title: Expression of the insulin receptor-related receptor is induced by the preovulatory surge of luteinizing hormone in thecal-interstitial cells of the rat ovary.
abstract: The insulin receptor-related receptor (IRR) is a member of the insulin receptor family that, on its own, recognizes neither insulin nor any of the identified insulin-related peptides. In both the nervous system and peripheral tissues, IRR mRNA is detected in cells that also express trkA, the nerve growth factor tyrosine kinase receptor. In the ovary, the trkA gene is transiently activated in thecal-interstitial cells of large antral follicles at the time of the preovulatory surge of gonadotropins. The present study shows that the IRR gene is expressed in the same ovarian compartment, that IRR mRNA content increases strikingly in these cells in the afternoon of the first proestrus, and that--as in the case of trkA mRNA--the increase is caused by gonadotropins. The IRR mRNA species primarily affected is that encoding the full-length receptor; its increased abundance was accompanied by a corresponding change in IRR protein content. An extensive molecular search using several approaches, including the screening of cDNA libraries and PCR amplification with degenerate primers, did not yield an IRR ligand. Phylogenetic analysis of 20 insulin-related sequences and 15 relaxin family peptides from selected vertebrates indicated that the mammalian genome is unlikely to contain an additional ligand expressed from a distinct gene that is closely related to the insulin family. Although the functional nature of the relationship between IRR and trkA receptors is unknown, the remarkable temporal and spatial specificities of their coordinated expression in the ovary before ovulation suggests that they target a functionally related set of downstream events associated with the ovulatory process.
authors.affiliation: Division of Neuroscience, Oregon Regional Primate Research Center, 505 N.W. 185th Avenue, Beaverton, Oregon 97006-3448, USA. disseng@ohsu.edu
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Dissen
authors.forename: Cecilia
authors.initials: C
authors.lastname: Garcia-Rudaz
authors.forename: Veronica
authors.initials: V
authors.lastname: Tapia
authors.forename: Luis F
authors.initials: LF
authors.lastname: Parada
authors.forename: Sheau-Yu Teddy
authors.initials: SY
authors.lastname: Hsu
authors.forename: Sergio R
authors.initials: SR
authors.lastname: Ojeda
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005260:Female; D005786:Gene Expression Regulation; D014644:Genetic Variation; D007986:Luteinizing Hormone / Q000378:metabolism*; D010053:Ovary / Q000166:cytology / Q000502:physiology*; D011359:Proestrus / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011972:Receptor, Insulin / Q000235:genetics*; D020917:Receptor, trkA / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013799:Theca Cells / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007986:Luteinizing Hormone; D011972:Receptor, Insulin; D020917:Receptor, trkA; C066542:insulin receptor-related receptor