Subfractionation of the head and trunk kidneys of the northern pike ( Esox lucius)

Because of the high tumour frequency in Northern pike, (E. lucius ), its stationary habitat, and the fact that this fish is a top predator, a study of the metabolism of xenobiotics in this species, was initiated. An earlier study involving whole-body autoradiography and scintillation counting demonstrated that when Northern pike are exposed to benzo(a)pyrene either in the diet or water, this xenobiotic and its metabolites are heavily concentrated in the liver, kidney, gall bladder and intestine. Consequently, we have subfractionated the kidney -- after dissection into head and trunk kidney, since these two regions differ histologically, functionally and in terms of benzo(a)pyrene uptake -- in order to obtain preparations suitable for the study of drug-metabolizing enzymes and to determine the subcellular distribution of these systems.