title: The expression of nuclear and membrane estrogen receptors in the European eel throughout spermatogenesis.
abstract: Estradiol (E2) can bind to nuclear estrogen receptors (ESR) or membrane estrogen receptors (GPER). While mammals possess two nuclear ESRs and one membrane GPER, the European eel, like most other teleosts, has three nuclear ESRs and two membrane GPERs, as the result of a teleost specific genome duplication. In the current study, the expression of the three nuclear ESRs (ESR1, ESR2a and ESR2b) and the two membrane GPERs (GPERa and GPERb) in the brain-pituitary-gonad (BPG) axis of the European eel was measured, throughout spermatogenesis. The eels were first transferred from freshwater (FW) to seawater (SW), inducing parallel increases in E2plasma levels and the expression of ESRs. This indicates that salinity has a stimulatory effect on the E2signalling pathway along the BPG axis. Stimulation of sexual maturation by weekly injections of human chorionic gonadotropin (hCG) induced a progressive decrease in E2plasma levels, and different patterns of expression of ESRs and GPERs in the BPG axis. The expression of nuclear ESRs increased in some parts of the brain, suggesting a possible upregulation due to a local production of E2. In the testis, the highest expression levels of the nuclear ESRs were observed at the beginning of spermatogenesis, possibly mediating the role of E2as spermatogonia renewal factor, followed by a sharply decrease in the expression of ESRs. Conversely, there was a marked increase observed in the expression of both membrane GPERs throughout spermatogenesis, suggesting they play a major role in the final stages of spermatogenesis.
authors: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal (Edificio 7G), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors: Marina
authors: M
authors: Morini
authors: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal (Edificio 7G), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors: David S
authors: DS
authors: Peñaranda
authors: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal (Edificio 7G), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors: M Carmen
authors: MC
authors: Vílchez
authors: Norwegian Institute of Fisheries and Aquaculture, Muninbakken 9-13, Breivika, P.O. Box 6122, NO-9291 Tromsø, Norway.
authors: Helge
authors: H
authors: Tveiten
authors: Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208, IRD 207, UPMC, UCN, UA, Paris, France.
authors: Anne-Gaëlle
authors: AG
authors: Lafont
authors: Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208, IRD 207, UPMC, UCN, UA, Paris, France.
authors: Sylvie
authors: S
authors: Dufour
authors: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal (Edificio 7G), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors: Luz
authors: L
authors: Pérez
authors: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal (Edificio 7G), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain. Electronic address: jfastu@dca.upv.es.
authors: Juan F
authors: JF
authors: Asturiano
mesh_terms: D000818:Animals; D004524:Eels / Q000378:metabolism*; D008297:Male; D013091:Spermatogenesis
keywords: Anguilla; ESR; GPER; Reproduction; Teleost