Changes in cortisol and thyroid hormone concentrations during early development and metamorphosis in the Japanese flounder, Paralichthys olivaceus

Whole-Body Cortisol Concentrations and Ontogeny of Aggressive Behavior in Yellowtail (Seriola quinqueradiataTemminck & Schlegel; Carangidae)

“…In metamorphosing Japanese flounder from larva to juvenile, increased tissue cortisol levels herald increased thyroid hormones (de Jesus et al, 1991) and cortisol accelerates dorsal fin-ray resorption in combination with thyroid hormones in vitro (de Jesus et al, 1990). Cortisol may have a role in metamorphosis of yellowtail as well as Japanese flounder, although there are differences in IRC patterns during metamorphosis between the two species (this study; Tanaka et al, 1995).…”

“…Combined extracts were dried and resuspended in 250-µl of carbon tetrachloride, followed by a second extraction with 250-µl of Gel-PBS (PBS containing 0.1% gelatin). One hundred µl Gel-PBS phase was used for IRC-RIA ( de Jesus et al, 1991). The efficiency of extraction of standard cortisol added to PBS-homogenate was 83.0±14.8% (n=4), and the displacement curve of the extracted sample was parallel to the standard curve (data not shown).…”

“…Recently, whole-body immunoreactive cortisol concentrations (IRC) during early development were reported for Japanese flounder Paralichthys olivaceus (de Jesus et al, 1991), chum salmon O. keta (de Jesus et al, 1991) and tilapia Oreochromis mossambicus (Hwang et al, 1992), focusing on the role of cortisol in development in relation to thyroid hormones, and in seawater adaptation. Moreover, IRC may indicate physiological stress in the early development of rainbow (Pottinger and Mosuwe, 1994;Barry et al,1995) and brown trout Salmo trutta (Pottinger and Mosuwe, 1994).…”

Stress responsiveness of the pituitary-interrenal axis during early life stages of common carp (Cyprinus carpio)

“…In tilapia (Oreochromis mossambicus), -melanocyte-stimulating hormone ( -MSH), which is produced in the pars intermedia of the pituitary gland, exerts corticotrophic actions in vitro (Lamers et al 1992). The interrenal corticosteroid cortisol has been shown to affect osmoregulation, energy metabolism, immune competence (Wendelaar Bonga 1997) and developmental processes, including hatching, growth and metamorphosis, in particular during stress (De Jesus et al 1991, Yamano et al 1991. The presence of cortisol has been demonstrated in eggs and larvae of various cichlid and salmonid species (De Jesus & Hirano 1992, Hwang et al 1992, Hwang & Wu 1993, Barry et al 1995.…”

“…The presence of cortisol has been demonstrated in eggs and larvae of various cichlid and salmonid species (De Jesus & Hirano 1992, Hwang et al 1992, Hwang & Wu 1993, Barry et al 1995. In unfertilised fish eggs, cortisol is already present because of maternal transfer during oogenesis (Feist et al 1990), but endogenous cortisol production does not start before hatching (De Jesus et al 1991, Hwang et al 1992, Hwang & Wu 1993, Barry et al 1995, Sampath-Kumar et al 1995. Studies on salmonid species have indicated that ACTH as well as -MSH immunopositive cells are present in the pituitary glands of fish embryos (Naito et al 1993, Saga et al 1993, although the onset of production of these hormones and their concentrations have not yet been determined in these life stages.…”