Erythromycin breath test as an assay of glucocorticoid-inducible liver cytochromes P-450. Studies in rats and patients.
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Differential regulation of liver P-450III cytochromes in choline-deficient rats: implications for the erythromycin breath test as a parameter of liver function.
Progressive liver fibrosis in rats develops when they are fed a diet deficient in choline. This diet also results in a pronounced and selective decrease in the liver microsomal content of a phase I drug-metabolizing enzyme belonging to the cytochrome P-450III gene family. Because P-450III cytochromes characteristically catalyze the N-demethylation of erythromycin, we believed that the productio...
متن کاملPurification of a human liver cytochrome P-450 immunochemically related to several cytochromes P-450 purified from untreated rats.
Among characterized forms of liver microsomal cytochromes P-450 in rats are four related isozymes (P-450f-i) notable for their lack of inducibility. Immunoblot analyses demonstrated that human livers microsomes contained several proteins related to these rat P-450s. A human liver P-450, termed HLx, was purified and found by immunochemical assays to resemble rat P-450g. Analysis of the NH2-termi...
متن کاملDistribution of cytochromes P-450, cytochrome b5, and NADPH-cytochrome P-450 reductase in an entire human liver.
In rat liver there appear to be significant differences between lobes in the concentration of individual cytochrome P-450 isozymes (Sumner and Lodola, Biochem Pharmacol 36: 391-393, 1987). Because studies in patients often rely on small pieces of liver obtained from diverse anatomical locations, it seemed important to determine if the cytochromes P-450 were also heterogeneously distributed in h...
متن کاملThree immunoidentical cytochromes P-450 from liver microsomes of phenobarbital-treated rats.
Three forms of cytochrome P-450 were purified to homogeneity from liver microsomes of Wistar-strain rats treated with phenobarbital. They had minimum mol.wts. of 52 000, 53 000 and 54 000 as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and are designated as P-450(L), P-450(M) and P-450(H) respectively. They were shown to be immunoidentical by Ouchterlony double-diffu...
متن کاملTopological Studies of Cytochromes P-450,,, and P-45011p in Bovine Adrenocortical Inner Mitochondrial Membranes
The topology of the steroid hydroxylase complexes in bovine adrenocortical mitochondria were studied by using controlled digestion with trypsin of purified inner mitochondrial membranes. Inhibition of steroid hydroxylase activity by trypsin was only observed in inner mitochondrial membranes which had been disrupted by various techniques. The steroid hydroxylase activity of intact inner membrane...
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ژورنال
عنوان ژورنال: Journal of Clinical Investigation
سال: 1989
ISSN: 0021-9738
DOI: 10.1172/jci113933