Differential Metabolic and Transcriptional Responses of Gilthead Seabream (Sparus aurata) Administered with Cortisol or Cortisol-BSA

Abstract

Cortisol is the main glucocorticoid hormone promoting compensatory metabolic responses of stress in teleosts. This hormone acts through genomic and membrane-initiated actions to exert its functions inside the cell. Experimental approaches, using exogenous cortisol administration, confirm the role of this hormone during short (minutes to hours)- and long-term (days to weeks) responses to stress. The role of membrane-initiated cortisol signaling during long-term responses has been recently explored. In this study, Sparus aurata were intraperitoneally injected with coconut oil alone or coconut oil containing cortisol, cortisol-BSA, or BSA. After 3 days of treatment, plasma, liver, and skeletal muscle were extracted. Plasma cortisol, as well as metabolic indicators in the plasma and tissues collected, and metabolism-related gene expression, were measured. Our results showed that artificially increased plasma cortisol levels in S. aurata enhanced plasma glucose and triacylglycerols values as well as hepatic substrate energy mobilization. Additionally, cortisol stimulated hepatic carbohydrates metabolism, as seen by the increased expression of metabolism-related genes. All of these responses, observed in cortisol-administered fish, were not detected by replicating the same protocol and instead using cortisol-BSA, which exclusively induces membrane-initiated effects. Therefore, we suggest that after three days of cortisol administration, only genomic actions are involved in the metabolic responses in S. aurata.

Cortisol and Dexamethasone Mediate Glucocorticoid Actions in the Lesser Spotted Catshark (Scyliorhinus canicula)

“…In this sense, maximum secretion rates occurred at physiological basal levels of glucose in the incubation medium (2.3 mM glucose), while they decreased drastically in the absence of external glucose, and to a lesser extent when glucose incubation medium concentration doubled (4.6 mM glucose). Further studies are mandatory to unravel this question, including analysis of transmembrane glucose transporters [ 34 , 81 ], the feasible action of non-canonical corticosteroid mechanisms [ 35 , 37 ] that may be associated to membrane processes, or the presence of glucosensors involved in GC actions.…”

“…Acute responses of cortisol include rapid glycolytic actions mediated by GR in teleost fish that affect liver and muscle [ 35 , 36 ]. Although GC actions in vertebrates from lampreys to mammals are well described, there is a knowledge gap on how these hormones affect sharks in the long and short term [ 37 ].…”

Ocean Acidification Alters the Acute Stress Response of a Marine Fish

“…After binding, the formed heterocomplex translocates to the nucleus, binds to the gluco-or melano-corticoid response element of the promotor gene and modulates the transcription of the target gene (Prunet, Sturm et al 2006). In addition, a rapid non-genomic signaling mediated by membrane receptors is likely to play a role in the cortisol driven acute stress adaptation in teleosts (Das, Thraya et al 2018, Aedo, Ruiz-Jarabo et al 2019, Aedo, Aravena-Canales et al 2021. Therefore, to better understand the impact of ocean acidification on fish life history traits, it is critical to evaluate its effects on the physiological stress response of fish.…”