Regulation of the glucocortocoid receptor mRNA levels in the gills of atlantic salmon (Salmo salar) during smoltification

• Main Authors: Mazurais, David, Ducouret, B., Tujague, M., Valotaire, Y., D'Cotta, Helena, Valotaire, Claudiane, Prunet, Patrick
• Other Authors: UPRES-A 6026 Endocrinologie moléculaire de la reproduction, Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Station commune de Recherches en Ichtyophysiologie, Biodiversité et Environnement (SCRIBE), Institut National de la Recherche Agronomique (INRA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1998
• Subjects: fish; salmonids; salmon; atlantic; glucocorticoid; gill; prolactin; poisson osseux; salmonidae; poisson; salmo salar; saumon de l'atlantique; glucocorticoïde; branchie; expression des gènes; smoltification; récepteur d'hormone; prolactine; transcrit; cortisol plasmatique; [SDV]Life Sciences [q-bio]; Atlantic salmon; Salmo salar
• Online Access: https://hal.archives-ouvertes.fr/hal-01593931; https://doi.org/10.1051/kmae:1998019

The regulation of the Glucocorticoid Receptor (GR) transcript was investigated in the gills of Atlantic salmon (Salmo salar) during the parr-smolt transformation. Sampling of parr and smolt fish was performed between December and July and in particular during the smoltification period occurring in spring. Quantification of GR transcripts revealed differences between the two groups in March and at the beginning of April. During these dates, the amounts of GR mRNA in parr gills were respectively three and two fold lower than those measured in smolts. In order to determine which factors are responsible for these differences, we studied the long-term effects of prolactin and Cortisol treatments on GR transcript in the gills of presmolt fish. The plasma levels of these two hormones respectively drop and rise during smoltification. Contrary to Cortisol long-term treatment which did not modify the amount of gill GR transcript, short-term treatment induced a significant decrease within 12 hours. Prolactin long-term treatment caused a significant increase of GR transcript abundance after 13 days of implant treatment. This result is unexpected with regard to those obtained in the smoltification analysis but is in agreement with previous studies performed in mammary gland revealing a positive control of PRL on GR in epithelial cells. Our data suggest that the regulation of the GR transcript during the parr-smolt transformation probably involves several hormonal factors. La régulation de l'expression du gène codant pour le récepteur aux glucocorticoïdes (GR) dans les branchies de saumon atlantique (Salmo salar) a été étudiée durant la période de smoltification. Les prélèvements chez les poissons parrs et smolts ont été réalisés entre décembre et juillet et plus particulièrement pendant la phase de smoltification au printemps. La quantification du transcrit GR a révélé des différences significatives entre les deux groupes en mars et début avril. Durant ces périodes, les quantités d'ARNm GR dans les branchies de saumons ...