Printedin USA. Drug Metabolism in Isolated Proximal Tubule Cells:

The mammalian kidney is composed of numerous cell popula-tions associated with the interstitial spaces, vasculature and various portions of the nephron. Not surprisingly, mammalian kidneys also exhibit an array of drug metabolizing activities, including the pyridine nucleotide-linked aldehyde dehydroge-nase(s) (ALDH). To define the ALDH activity in segment 2 of the proximal tubule, a portion of the nephron which frequently shows drug-induced pathology, proximal tubules were isolated by purely mechanical methods from female rabbits. lsopycnic centrifugation of tubule-derived postnuclear supernates in lin-ear sucrose gradients resulted in propionaldehyde (5 mM)-driven ALDH activity being distributed in a manner consistent with both a mitochondrial and cytosolic localization. Mitochon-drial and cystosolic fractions yielded biphasic reciprocal plot