title: Temperature modulates testis steroidogenesis in European eel.
abstract: This study evaluates the effects of temperature on hCG-induced spermatogenesis in European eel (Anguilla anguilla), subjected to three thermal regimes: T10: 10°C (first 4weeks), 15°C (next 3weeks) and 20°C (last 6weeks); T15: 15°C (first 4weeks) and 20°C (last 9weeks); and T20: constant 20°C for the duration of the experiment. At 10°C, maturation stopped in the A spermatogonial stage (SPG1), and no further maturation was observed until the temperature was ≥15°C. With the aim of explaining these results, the influence of temperature on steroidogenic enzyme gene expression and steroid synthesis was tested. The initial synthesis of androgens (T and 11-KT) increased at SPG1, and was not influenced by temperature. Likewise, the gene expression of the steroidogenic enzymes linked to androgen synthesis (aacyp11a1, aacyp17-I and aa11βHSD) also increased at SPG1. In contrast, no correlation was seen between the increase in E2 and the aacyp19a1 gene expression peak in the testes, with E2 increasing as a consequence of the seawater acclimation carried out before hormonal treatment, and peaking the aacyp19a1 gene expression at B spermatogonial stage (SPG2). Aacyp21 gene expression was also higher at SPG2, and this stage was only reached when the rearing temperature was ≥15°C. In conclusion, androgen synthesis is not dependent on temperature, but further maturation requires higher temperatures in order to induce a change in the steroidogenic pathway towards estrogen and progestin synthesis. This study demonstrates that temperature plays a crucial role in European eel maturation, even perhaps controlling gonad development during the reproductive migration.
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain.
authors.forename: David S
authors.initials: DS
authors.lastname: Peñaranda
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain.
authors.forename: Marina
authors.initials: M
authors.lastname: Morini
authors.affiliation: Norwegian Institute of Fisheries and Aquaculture, Muninbakken 9-13, Breivika, P.O. Box 6122, NO-9291 Tromsø, Norway.
authors.forename: Helge
authors.initials: H
authors.lastname: Tveiten
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Vílchez
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Gallego
authors.affiliation: Leiden University, Institute of Biology, Leiden, Gorlaeus Laboratories, POB 9505, 2300 RA Leiden, The Netherlands.
authors.forename: Ron P
authors.initials: RP
authors.lastname: Dirks
authors.affiliation: Leiden University, Institute of Biology, Leiden, Gorlaeus Laboratories, POB 9505, 2300 RA Leiden, The Netherlands.
authors.forename: Guido E E J M
authors.initials: GE
authors.lastname: van den Thillart
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain.
authors.forename: Luz
authors.initials: L
authors.lastname: Pérez
authors.affiliation: Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera, s/n, 46022, Valencia, Spain. Electronic address: jfastu@dca.upv.es.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Asturiano
mesh_terms: D000728:Androgens / Q000096:biosynthesis*; D000818:Animals; D004524:Eels / Q000378:metabolism / Q000502:physiology*; D015870:Gene Expression; D008297:Male; D013737:Testis / Q000378:metabolism*
chemical_list: D000728:Androgens
keywords: Anguilla anguilla; Gene expression; Spermatogenesis; Steroid; Temperature