title: Corticotropin-releasing factor (CRF) and CRF-binding protein expression in and release from the head kidney of common carp: evolutionary conservation of the adrenal CRF system.
abstract: Corticotropin-releasing factor (CRF) plays a central role in the regulation of the stress axis. In mammals, CRF as well as its receptors and its CRF-binding protein (CRF-BP) are expressed in a variety of organs and tissues outside the central nervous system. One of these extrahypothalamic sites is the adrenal gland, where the paracrine actions of adrenal CRF influence cortical steroidogenesis and adrenal blood flow. Although the central role of CRF signaling in the initiation and regulation of the stress response has now been established throughout vertebrates, information about the possible peripheral presence of CRF in earlier vertebrate lineages is scant. We established the expression of CRF, CRF-BP, and the CRF receptor 1 in a panel of peripheral organs of common carp (Cyprinus carpio). Out of all the peripheral organs tested, CRF and CRF-BP are most abundantly expressed in the carp head kidney, the fish equivalent of the mammalian adrenal gland. This expression localizes to chromaffin cells. Furthermore, detectable quantities of CRF are released from the intact head kidney following in vitro stimulation with 8-bromo-cAMP in a superfusion setup. The presence of CRF and CRF-BP within the chromaffin compartment of the head kidney suggests that a pathway homologous to the mammalian intra-adrenal CRF system is present in the head kidney of fish. It follows that such a system to locally fine-tune the outcome of the centrally initiated stress response has been an integral part of the vertebrate endocrine system since the common ancestor of teleostean fishes and mammals.
authors.affiliation: Department of Animal Physiology, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
authors.forename: Mark O
authors.initials: MO
authors.lastname: Huising
authors.forename: Lieke M
authors.initials: LM
authors.lastname: van der Aa
authors.forename: Juriaan R
authors.initials: JR
authors.lastname: Metz
authors.forename: Aurélia
authors.initials: A
authors.lastname: de Fátima Mazon
authors.forename: B M Lidy Verburg-van
authors.initials: BM
authors.lastname: Kemenade
authors.forename: Gert
authors.initials: G
authors.lastname: Flik
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000311:Adrenal Glands / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002347:Carps / Q000378:metabolism*; D002352:Carrier Proteins / Q000032:analysis* / Q000378:metabolism; D019439:Chromaffin Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D015870:Gene Expression; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000032:analysis; D011863:Radioimmunoassay; D018019:Receptors, Corticotropin-Releasing Hormone / Q000032:analysis / Q000235:genetics; D013268:Stimulation, Chemical; D000099052:CRF Receptor, Type 1
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; C067133:corticotropin releasing factor-binding protein; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone