Liver channel catfish

Fish may be more resistant to lead than mammals. For example, isolated liver hepatocytes of channel catfish were about 40 times more resistant to lead than rat liver hepatocytes as judged by ALAD inhibition (Conner and Fowler 1994). 

Stalling and coworkers (11) studied the metabolism of DEHP and dibutyl phthalate by channel catfish liver microsomes. They found that the respective monoesters and more polar metabolites were produced, but that DEHP was metabolized to a much lesser extent than dibutyl phthalate. Additional studies (Table V) showed that the production of the respective monoesters was unaffected by the presence of NADPH, but that the production of more polar metabolites is very dependent upon NADPH. The reasons for the apparent lack of a requirement for oxygen are unclear... 

When channel catfish were intravascularly dosed with radiolabeled acriflavine or proflavine, total residue equivalent concentrations were highest in the excretory organs and lowest in muscle, fat, and plasma (84). In proflavine-dosed fish, residues in liver and trunk kidney were composed primarily of glucuronosyl and acetyl conjugates of proflavine residues in muscle were composed mostly of the parent drug. In acriflavine-dosed fish, the parent compound made up 90% of the total residues in all tissues examined. 

The distribution and elimination of SARA from tissue of juvenille channel catfish was evaluated as the loss of radioactivity of SARA Cl 4 in liver, kidney, skin, and skinless fillet. An HPLC with fluorescence detection, in-line radiometric detection, and gradient elution was applied (203). The pharmacokinetics of ENRO in the milk of lactating cows was studied by HPLC, and it was found that a marked proportion of ENRO was metabolized to CIPRO (204). 

Hogan and Knowles (1968) examined the OPA anhydrases of liver homogenates from the bluegill sunfish, Lepomis macrochirus, and the channel catfish, Ictalarus punctatus. Initially, a 1.5% (w/v) homogenate of the excised livers from each species was determined to hydrolyze 10 2M concentrations... 

Gallagher, E.P., G.L. Kedderis and R.T. Digiulio. Glutathione S-Irans[ erase-mediated chlorothalonil metabolism in liver and gill subcellular fractions of channel catfish. Biochem. Pharmacol. 42 139-145, 1991. 

Schlenk, D., M.J. Ronis, C.L. Miranda and D.R. Buhler. Channel catfish liver monooxygenases. Immunological characterization of constitutive cytochromes P450 and the absence of active flavin-containing monooxygenases. Biochem. Pharmacol. 45 217-221, 1993. 

Gallagher, E.P., Di Giulio, R.T., 1992. A comparison of glutathione-dependent enzymes in liver, gills and posterior kidney of channel catfish. Comp. Biochem. Physiol. 102C, 543-547. 

Two further studies have been reported involving ihe intraperitoneal injection of methyl mercury compounds into fish. Kendall (1975) administered 12 mg/kg of mercury by this means to the channel catfish Ictalurus punctatus and observed inhibition of succinic hydrogenase activity and substantial kidney necrosis. Manen et al. (1976) in a similar investigation with the flounder Pseudopleuronectus americanus noted a marked increase (5 to 7x) in enzyme activity in the liver and kidney. 

LEAP-2 was the second liver-expressed AMP discovered in vertebrates. LEAP-2 molecules are a distinct family of AMPs, since they show no similarity with hepcidins (or LEAP-1) or defensins. For instance, LEAP-2 has only four cysteines which form two disulfide bonds. To date, fish LEAP-2 AMPs have only been reported in rainbow trout,channel catfish Ictal-urus punctatus), blue catfish (Ictalurus furcatus) and grass carp (Cteno-pharyngodon idella) ... 

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