Distribution and induction of alkoxyresorufin O-dealkylases and gamma-glutamyl transpeptidase in porcine ciliary epithelium.
Nonpigmented epithelial (NPE) cells and pigmented epithelial (PE) cells were separated from porcine ciliary body by a simple surgical procedure. Using primary cultures of separated cells, basal and induced activities of 7-ethoxy resorufin (ER) O-dealkylase, 7-pentoxy resorufin (PR) O-dealkylase, and gamma-glutamyl transpeptidase (GGTP) were determined. These enzymatic activities were primarily associated with NPE cells; PE cells showed little or no activity. Treatment of NPE cells with phenobarbital for 48 hours resulted in about 5-fold increase in PR O-dealkylase activity but not ER-Odealkylase activity. Conversely, 3-methylcholanthrene treatment increased ER O-dealkylase activity 5-6 times over the basal level but had little or nor effect on PR O-dealkylase activity. The enhancement of enzymatic activities by inducers was completely inhibited by cyclohexamide. NPE cells exhibited higher GGTP activity than PE cells. Both phenobarbital and 3-methylcholanthrene augmented the GGTP activity of NPE cells but not of PE cells. The physiological significance of the regional differences in enzyme distribution was discussed.
Sakamoto
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S
Kresge Eye Institute, Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI.
Shichi
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H
D000818:Animals; D002478:Cells, Cultured; D002924:Ciliary Body / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D003513:Cycloheximide / Q000494:pharmacology; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology; D008748:Methylcholanthrene / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D013552:Swine; D005723:gamma-Glutamyltransferase / Q000235:genetics / Q000378:metabolism*
D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D003513:Cycloheximide; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D005723:gamma-Glutamyltransferase; D010634:Phenobarbital