Radioactive assay for aryl hydrocarbon hydroxylase. Improved method and biological importance

Variation in hepatic aryl hydrocarbon hydroxylase activity in flounder,Platichthys flesus: A baseline study

“…The (14C) B(a)P was diluted with unlabelled B(a)P and purified according to the method described by Van Cantford et al (1977), Fish capture and treatment Flounder (Platichthys flesus) were caught by beach seine at Sotra, an island southwest of Bergen (Norway). This is an area with no known sources of organic contamination.…”

“…The enzyme assay was a slight modification of the method described by Van Cantford et al (1977). The reaction mixture contained: 0.40 mM NADP, 2.5 mM glucose-6-phosphate, 50 mM Tris buffer (pH 7.4), 5ram Mg C12, 0.08 mM B(a)P dissolved in 10 ~tl of acetone and PMS (4-5 mg protein/ml) in a total volume of 0.5 ml.…”

Identification of a Novel Cis-acting Negative Regulatory Element Affecting Expression of the CYP1A1 Gene in Rat Epidermal Cells

“…Aryl Hydrocarbon Hydroxylase (AHH) Assay-AHH activity was determined as described previously (26,37). Near confluent cultures were incubated for 12 h with 5 nM TCDD or solvent alone (0.05% Me 2 SO), rinsed twice, and then incubated in 5 ml of serum-free medium containing 3.5 M […”

Induction of drug‐metabolizing enzymes by tricyclic antidepressants in human liver: characterization and partial resolution of cytochromes P‐ 450.

“…Aniline hydroxylation and 4-nitroanisole demethylation (Mazel, 1971), benzo(a)pyrene hydroxylation (Van Cantfort et al, 1977), ethoxycoumarin deethylation (Aitio, 1978) and the demethylation of benzphetamine, chlorcyclizine and ketotifen estimated by the formation of formaldehyde (Nash, 1953) were assayed as previously described (Kremers et al, 1981). Conditions for the demethylation of 1 nim chlorcyclizine and 1 mm ketotifen were verified to be optimal as a function of incubation time, protein and substrate concentrations.…”