title: Characterization of Oryzias latipes glucocorticoid receptors and their unique response to progestins.
abstract: Various receptor bioassays, including estrogens, androgens and thyroid hormones, have been developed and applied successfully for assessing hormone function in a wide range of animal species, including fish. In fish, corticosteroids play a pivotal role in physiology as they do in mammals, but far less is known about the corticosteroid receptor system in fish compared with in mammals. Here we established a transient transactivation assay using the Japanese medaka, Oryzias latipes, glucocorticoid receptors (olGRs) and mineralocorticoid receptor to analyse their functional properties in a fish. We found that olGR2 was highly responsive to glucocorticoids, similar to the human GR, whereas the olGR1 subtype was minimally responsive. Thus, olGR2 most likely mediates glucocorticoid signaling in medaka. We further tested crosstalk between GRs and other steroid hormones, and found that progestins could activate or inactivate olGR2-mediating transcription, depending on the presence or absence of cortisol. The transactivation assays developed for medaka GRs provide tools to gain useful insights into corticosteroid signaling in fish and for in vitro screening of environmental substances activating GRs.
authors: Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, 444-8787, Japan.
authors: Shinichi
authors: S
authors: Miyagawa
authors: Anke
authors: A
authors: Lange
authors: Saki
authors: S
authors: Tohyama
authors: Yukiko
authors: Y
authors: Ogino
authors: Takeshi
authors: T
authors: Mizutani
authors: Tohru
authors: T
authors: Kobayashi
authors: Norihisa
authors: N
authors: Tatarazako
authors: Charles R
authors: CR
authors: Tyler
authors: Taisen
authors: T
authors: Iguchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D052244:Endocrine Disruptors / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D009928:Organ Specificity; D009990:Oryzias / Q000378:metabolism*; D011372:Progestins / Q000494:pharmacology*; D020239:Receptor Cross-Talk; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D018161:Receptors, Mineralocorticoid / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D052244:Endocrine Disruptors; D011372:Progestins; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid
keywords: glucocorticoid receptor; medaka; progestins; reporter gene assay; species differences