Fishing a hypothetical membrane receptor in the gilthead sea bream (Sparus aurata): role in acute stress
Trabajo presentado en el XII Conference of the Iberian Association for Comparative Endocrinology (AIEC), celebrado en Faro (Portugal), del 26 al 28 de septiembre de 2019. ; Cortisol is the most important hormone involved in the regulation of neuroendocrine stress response in teleosts. Effects of this hormone are mediated through its intracellular receptors, although membrane components are also involved, with unclear roles during the stress response. In this work, the contribution of membrane-initiated cortisol actions on stress-related parameters and metabolism-related genes in gilthead sea bream (Sparus aurata) were evaluated. Two in vivo experiments were performed. In the first, fish were administered with vehicle, BSA, cortisol and cortisol-BSA (membrane impermeable analogue) dissolved in saline (PBS 1X). In the second, the same treatments were replicated but using coconut oil as a vehicle. Fish were sampled after one and six hours (first experiment) and after three days (second experiment). Plasma cortisol, glucose and lactate levels were measured, and hepatic transcript levels of key genes involved in glucose metabolism, like glucose-6-phosphatase (g6pc), phosphoglycerate mutase 1 (pgam1), among others, were also analyzed. Fish implanted with each version of cortisol in both in vivo experiments reached plasma levels typically observed under an acute stress in S. aurata. Cortisol and cortisol-BSA increased glucose and lactate plasma levels after six hours of treatment. However, cortisol, but not cortisol-BSA, maintained increased plasma glucose levels after three days of treatment. Analysis by qPCR showed that expression of g6pc increased after one hour of cortisol and cortisol-BSA administration. However, cortisol, but not cortisol-BSA, maintained the g6pc up-regulation after three days. Our results suggested that membrane-initiated cortisol actions contributed to the regulation of early metabolic adaptations in S. aurata submitted to an emulated acute stress situation. ; This work was funded by Spanish Ministry of Science, Innovation and Universities - MICINN (AGL2016-76069-C2-1-R) awarded to JMM. The authors belong to the Fish Welfare and Stress Network (AGL2016-81808-REDT), supported by the Agencia Estatal de Investigación (MICINN, Spanish Government). ; Peer reviewed