The Combined Action of Polycyclic Aromatic Hydrocarbons (PAH) on the Activity of Aryl Hydrocarbon Hydroxylase (AHH): InVitro Assay
PAHs are widespread contaminants in our environment and may be a major cause of cancer in human beings. It is accepted that PAHs are not active per se, but require some kind of metabolic activation by monooxygenase enzymes for the manifestation of their carcinogenic activity. A wide variety of PAHs are present simultaneously in the environment, so the potential for interaction with two or more PAHs in a biological system is great. We have recently studied the combined action of two or three PAHs on AHH activity of rat methylcholanthrene-induced liver microsomes. The experiment is designed according to the orthogonal L4 (23) and L8 (27) tables. Determination of AHH activity is cased on the use of radioactivity-labelled substrate—[3H] BaP, and the radioactivity of the lower phase of the reaction medium is quantified by scintillation counting. Ten PAHs are divided into 6 groups for studying the combined action of two or three factors. The nedium containing [3H]BaP only serves as the control group, and its scintillation counting value is 100 when compared with the test groups. The results show that all the test groups exhibit a varying degree of inhibitory action on AHH activity.