Suppression by Organochlorines of the Response to Adrenocorticotrophin of the Interrenal Tissue in Sarotherodon Aureus (Teleostei)

Ilan, Z.; Yaron, Z.

doi:10.1677/joe.0.0870185

Cited by 28 publications

(25 citation statements)

References 14 publications

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“…As cannulation has been shown to be stressful and result in higher plasma cortisol levels in trout (Gamperl et al 1994), the absence of any difference in elevated plasma cortisol levels between the sham-and BNF-treated fish argues against the possibility that BNF affects the corticosteroid biosynthetic pathway. Consequently, our results favour the hypothesis that the abolition of interrenal sensitivity to ACTH stimulation in BNFinjected trout is due to receptor downregulation and/or desensitization, as proposed earlier for tilapia exposed to o,p-DDD (Ilan & Yaron 1980). The absence of a difference in plasma cortisol concentration after BNF injection, despite the abolition of interrenal sensitivity to ACTH, suggests the possibility that BNF affects the plasma clearance rate of cortisol in fish.…”

Section: Discussionsupporting

confidence: 88%

“…This absence of a response to ACTH may be due to the effect of BNF on either ACTH receptor dynamics and/or the steroidogenic pathway in trout interrenal tissue. The absence of ACTHstimulated cortisol production has been shown previously in the interrenal tissue of tilapia treated with the organochlorine insecticide 1,1-dichloro-2,2-(o-chlorophenyl)-2-(pchlorophenyl)ethane (o,p-DDD) (Ilan & Yaron 1980). This suppressive effect of the insecticide, however, was abolished in the presence of N 6 ,O 2 -dibutyryl cAMP.…”

Section: Discussionmentioning

confidence: 66%

“…This suppressive effect of the insecticide, however, was abolished in the presence of N 6 ,O 2 -dibutyryl cAMP. As cAMP is a major second messenger for ACTH stimulation in fish, these results suggest that the contaminant effect on the pituitaryinterrenal axis may be attributed to ACTH receptor downregulation and/or desensitization (Ilan & Yaron 1980). Recent studies have raised the possibility that P450 inducers may also affect the steroidogenic enzyme pathway of cortisol production.…”

Section: Discussionmentioning

confidence: 95%

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beta-Naphthoflavone abolishes interrenal sensitivity to ACTH stimulation in rainbow trout

Wilson¹,

Vijayan²,

Kennedy³

et al. 1998

Journal of Endocrinology

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We report for the first time that -naphthoflavone (BNF) abolishes ACTH stimulation of cortisol production in rainbow trout (Oncorhynchus mykiss). There was significantly higher hepatic cytochrome P450 content and ethoxyresorufin O-de-ethylase and uridine-5 -diphosphoglucuronic acid transferase activities in BNFtreated fish than in sham-treated controls. BNF did not significantly effect either plasma turnover or tissue distribution of [ 3 H]cortisol-derived radioactivity. Hepatic membrane fluidity and hepatocyte capacity for cortisol uptake were not altered by BNF as compared with the sham-treated fish. These results taken together suggest that BNF does not affect cortisol-clearance mechanisms in trout. A 3 min handling disturbance period elicited a plasma cortisol response in the sham-treated fish; however, the response in the BNF-treated fish was muted and significantly lower than in the sham fish. This in vivo response corroborates the lack of interrenal sensitivity to ACTH in vitro in the BNF-treated fish, suggesting that BNF affects the ACTH pathway in trout. Our results suggest the possibility that cytochrome P450-inducing compounds may affect cortisol dynamics by decreasing interrenal responsiveness to ACTH stimulation in fish, thereby impairing the physiological responses that are necessary for the animal to cope with the stressor.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 95%

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beta-Naphthoflavone abolishes interrenal sensitivity to ACTH stimulation in rainbow trout

Wilson¹,

Vijayan²,

Kennedy³

et al. 1998

Journal of Endocrinology

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“…3, Table 11) may be explained by a failure of the interrenal tissue in response to ACTH. This assumption is corroborated by the previous finding that superfused interrenal tissue from S. aureus pretreated with o,p'DDD, or in the presence of this organochlorine in the superfusion medium, failed to respond to ACTH (Ilan & Yaron, 1980b).…”

Section: Discussionsupporting

confidence: 82%

Interference of o,p'DDD with interrenal function and cortisol metabolism in Sarotherodon aureus (Steindachner)

Ilan

Yaron

1983

Journal of Fish Biology

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The purpose of this study was to investigate possible effects of organochlorine residues on cortisol balance in a freshwater fish. The combined stress of netting, handling and blood sampling in Sarotherodon aureus normally results in a twofold increase of circulating cortisol, within 30-60 min. Fish treated with o,p'DDD (50 mg kg-1) had higher resting level of cortisol than before treatment (1 55.8 k 12.7 v. 86.9 f 11.2 ng m1-I; n = 16). No further increase in cortisol level occurred in these fish after exposure to stress; this inability to respond was maintained for more than 120 days. A recovery of the response to ACTH by superfused interrenal tissue from the treated fish was observed 255 days after treatment. Successive blood sampling of o,p'DDD-treated fish, injected intracardially with labelled cortisol, have shown that the half-life of the steroid in the circulation is prolonged by 370% compared with controls. The hepatic metabolism of cortisol was studied by incubating liver slices with the labelled hormone. Hepatic tissue from o,p'DDD-treated fish metabolized cortisol slower than livers from controls. The high resting level of cortisol in plasma of fish treated with o,p'DDD may be attributed to the retarded metabolism of the steroid by the liver. The lack of augmented cortisol levels in response to stress is attributed to the interference of the organochlorine with the response of the interrenal tissue to the stress-induced surge of endogenous ACTH.

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“…Consistent with this mechanism of action, PCBs are known to interfere with the P450 enzyme systems in fish (Goksoyr and Forlin, 1992). The PCB data presented here differ from those of an earlier study where ACTH-, but not cAMP-, stimu lated in vitro cortisol release was impaired after treat ment of the tilapia Sarotherodon aureus with the organochlorine insecticide o,p-D D D (Ilan and Yaron, 1980). Therefore, suppression of ACTH-stimulated cortisol release from the interrenal tissues might be a general response to PCBs and structurally related compounds, but evidently the mechanisms of action differ.…”

Section: Influence On the Hypothalcimiis-pituitaryinterrenal Axiscontrasting

confidence: 54%

Interrenal Stress Responsiveness of Tilapia (Oreochromis mossambicus) Is Impaired by Dietary Exposure to PCB 126

Quabius

Balm

Bonga

1997

General and Comparative Endocrinology

101

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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 (Orcochromis mossambicus) is compromised by short-term exposure to PCB 126, fish of both sexes were fed diets containing PCB 126 (50 M-g/kg fish • day) for 5 days. In the first approach, which was performed twice, fish were acutely stressed for 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). After 5 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 ap proach, 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 PCBtreated tilapia. Adrenocorticotropic hormone (ACTH)-and cAMP-stimulated in vitro cortisol release from superfused head kidneys was lower in tissues from tilapia exposed to PCB 126 than 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, whereas plasma ACTH levels were higher in confined PCB-fed fish than in confined controls. PCB-fed fish showed a lower hypergly cemic response to confinement than control fish. Confine ment 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 did not affect Na,K-ATPase activities and plasma ion concentrations, it is concluded that the effects of PCB 126 on the HPI axis in tilapia are not secondary to ionoregulatory dysfunction © 1997 A cadem ic P ress

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Suppression by Organochlorines of the Response to Adrenocorticotrophin of the Interrenal Tissue in Sarotherodon Aureus (Teleostei)

Cited by 28 publications

References 14 publications

beta-Naphthoflavone abolishes interrenal sensitivity to ACTH stimulation in rainbow trout

beta-Naphthoflavone abolishes interrenal sensitivity to ACTH stimulation in rainbow trout

Interference of o,p'DDD with interrenal function and cortisol metabolism in Sarotherodon aureus (Steindachner)

Interrenal Stress Responsiveness of Tilapia (Oreochromis mossambicus) Is Impaired by Dietary Exposure to PCB 126

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