Hepatic Biotransformation of Environmental Xenobiotics in Six Strains of Rainbow Trout (Salmo gairdneri)

1976 ◽  
Vol 33 (4) ◽  
pp. 666-675 ◽  
Author(s):  
Mark G. Pedersen ◽  
William K. Hershberger ◽  
Prince K. Zachariah ◽  
Mont R. Juchau
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Aminobenzoic Acid ◽  
Aryl Hydrocarbon Hydroxylase ◽  
Nitrobenzoic Acid ◽  
Aryl Hydrocarbon ◽  
Influence Gene Expression ◽  
Stimulation Of ◽  
Hepatic Biotransformation

Six strains of rainbow trout (Salmo gairdneri), each geographically and genetically distinct, were compared in relation to their capacity for hepatic hydroxylation of aniline and benzo[a]pyrene, and reduction of p-nitrobenzoic acid to p-aminobenzoic acid, in vitro. The effects of 3-methylcholanthrene on stimulation of nitro reductase and aryl hydrocarbon hydroxylase were examined. For the three systems studied, a significant pattern was observed with respect to each strain’s capacity for metabolism. Induction experiments suggested that environment may influence gene expression. Enzyme kinetics and spectral properties were also examined, and mechanisms causing variability within and among strains were discussed.

Influence of thiol substances on in vitro and in vivoL-thyroxine deiodination in rainbow trout, Salmo gairdneri

1984 ◽  
Vol 62 (8) ◽  
pp. 1495-1501 ◽  
Author(s):  
J. G. Eales ◽  
Shirley Shostak ◽  
Catherine G. Flood
Keyword(s):  
Rainbow Trout ◽  
Reduced Glutathione ◽  
Salmo Gairdneri ◽  
Physiological Conditions ◽  
Low Concentrations ◽  
Dtt Dithiothreitol ◽  
High Concentrations ◽  
Stimulation Of

The effects of the thiols DTT (dithiothreitol) and GSH (reduced glutathione) on hepatic in vitro and in vivo T4 (L-thyroxine) deiodination by rainbow trout held at 11 °C were studied. Hepatic deiodination increased progressively over the DTT range of 0.02–20 mM. GSH was less potent than DTT at low concentrations and strongly inhibited deiodination at high concentrations (> 1 mM). Hepatic deiodination was not increased by 1 mM NADPH or anaerobic conditions and was enhanced and not inhibited by the GSH inhibitor, diamide (2.5 mM), indicating that the low T4 deiodination in the absence of DTT is not due to endogenous GSH deficiency. Intraperitoneally injected GSH consistently increased plasma levels of 125I and [125I]-3,5,3′-triiodo-L-thyronine (T3) in fed or starved [125I]T4-injected trout, suggesting a GSH stimulation of extrahepatic T4 deiodination. However, injected GSH did not elevate plasma T3 concentrations. This was probably due to a demonstrated GSH stimulation of plasma T4 and T3 clearance. Force-fed GSH did not increase [125I]T4 deiodination. It is concluded that exogenous thiols can enhance T4 deiodination both in vitro and in vivo. However, availability of neither endogenous nor dietary GSH appears to regulate T4 deiodination under physiological conditions, including altered nutritional state.

In vitro screening of the effect of hydrazine derivatives on hepatic aryl hydrocarbon hydroxylase activity

1983 ◽  
Vol 14 (3) ◽  
pp. 365-368
Author(s):  
Walid A. Al-Turk ◽  
Chitta R. Raha ◽  
Wallace J. Murray ◽  
Ronald J. Heinicke
Keyword(s):  
In Vitro Screening ◽  
Aryl Hydrocarbon Hydroxylase ◽  
Hydroxylase Activity ◽  
Hydrazine Derivatives ◽  
Aryl Hydrocarbon ◽  
Aryl Hydrocarbon Hydroxylase Activity
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