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Titolo:
INTERRENAL STRESS RESPONSIVENESS OF TILAPIA (OREOCHROMIS-MOSSAMBICUS)IS IMPAIRED BY DIETARY EXPOSURE TO PCB-126
Autore:
QUABIUS ES; BALM PHM; BONGA SEW;
Indirizzi:
UNIV NIJMEGEN,DEPT ANIM PHYSIOL,TOERNOOIVELD 1 NL-6525 ED NIJMEGEN NETHERLANDS
Titolo Testata:
General and comparative endocrinology
fascicolo: 3, volume: 108, anno: 1997,
pagine: 472 - 482
SICI:
0016-6480(1997)108:3<472:ISROT(>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLYCHLORINATED-BIPHENYLS PCBS; TROUT ONCORHYNCHUS-MYKISS; SALVELINUS-FONTINALIS; COHO SALMON; CORTISOL; FISH; TOXICOLOGY; DIBENZOFURANS; METABOLISM; MEMBRANES;
Keywords:
CORTISOL; ADRENOCORTICOTROPIC HORMONE; ENDOCRINE DISRUPTION; PITUITARY-INTERRENAL AXIS; STRESS; TELEOST FISH; PCB 126;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
46
Recensione:
Indirizzi per estratti:
Citazione:
E.S. Quabius et al., "INTERRENAL STRESS RESPONSIVENESS OF TILAPIA (OREOCHROMIS-MOSSAMBICUS)IS IMPAIRED BY DIETARY EXPOSURE TO PCB-126", General and comparative endocrinology, 108(3), 1997, pp. 472-482

Abstract

Activation of the hypothalamus-pituitary-interrenal (HPI) axis is characteristic of stress responses, which may result from a variety of environmental challenges. To investigate whether the stress response, and in particular the HPI axis, in tilapia (Oreochromis mossambicus) is compromised by short-term exposure to PCB 126, fish of both sexes werefed diets containing PCB 126 (50 mu g/kg fish day) for 5 days. In thefirst approach, which was performed twice, fish were acutely stressedfor periods varying between 1 and 30 min at the end of the exposure period; in the second approach fish were sampled at the end of the exposure period either at rest or after 2 h of stress (confinement). After5 days, the body weights in all experiments were significantly lower in PCB-fed fish than in control fish. There were no changes in basal plasma glucose levels, plasma ion concentrations, or branchial, renal, and intestinal Na,K-ATPase activity following PCB exposure. In the first experimental approach, in which fish experienced acute sampling stress, plasma cortisol levels reached lower levels in PCB-fed fish than in controls. This suggests an impaired ability to acutely activate interrenal steroidogenesis in PCB-treated tilapia. Adrenocorticotropic hormone (ACTH)-and cAMP-stimulated in vitro cortisol release from superfused head kidneys was lower in tissues from tilapia exposed to PCB 126than in tissues from control animals. This effect persisted after 24 h in vitro, which, together with the high PCB 126 concentrations measured in the head kidneys of PCB-fed fish, may indicate direct toxic effects on the interrenal cells. The second experimental approach demonstrated that basal plasma cortisol and ACTH levels were not influenced by PCB treatment, but that the basal ACTH content of the rostral pars distalis (RPD) of the pituitary gland of PCB-fed fish was lower than that of control fish. After 2 h confinement, plasma cortisol levels and ACTH content of the RPD rose to similar values in both groups, whereasplasma ACTH levels were higher in confined PCB-fed fish than in confined controls. PCB-fed fish showed a lower hyperglycemic response to confinement than control fish. Confinement resulted in similarly elevated renal and intestinal Na,K-ATPase activities in both PCB-fed and control fish; branchial enzyme activities were not affected. Since PCB didnot affect Na,K-ATPase activities and plasma ion concentrations, it is concluded that the effects of PCB 126 on the HPI axis in tilapia arenot secondary to ionoregulatory dysfunction. (C) 1997 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 19:25:30