title: L-buthionine sulfoximine-induced loss of glutathione does not elicit PGH synthase inactivation in cultured bovine lens epithelial cells.
abstract: Previous studies from this laboratory have indicated that exposure of cultured bovine lens epithelial cells (BLECs) to minimal essential medium (MEM) containing 40 mM galactose (Gal) for as short a duration as 20 h results in a reduction of microsomal prostaglandin biosynthesis as demonstrated by a decrease in PGH synthase activity (Invest. Ophthalmol. Vis. Sci. 29:1452-1460, 1988). The present study shows that upon brief exposure of BLECs to Gal, the cellular content of glutathione (GSH) decreases as galactitol increases. Studies were therefore undertaken to establish whether a positive correlation existed between polyol accumulation, GSH content and the activity of PGH synthase (an enzyme known to auto-oxidize) utilizing BLECs exposed to hypergalactosemic conditions. The inhibitor of glutathione biosynthesis, L-buthionine sulfoximine (L-BSO) was used in order to lower the intracellular pool of GSH in MEM-incubated cells to a level below that routinely observed in Gal-incubated cells, under conditions whereby no galactitol accumulation had occurred. The galactitol content was 92 nmol/micrograms PO4 in Gal-incubated cells after a 20 h exposure period; no detectable level of galactitol was observed in BLECs maintained in galactose-free MEM. L-(BSO) (1 mM) was co-administered to BLECs maintained in either MEM or Gal for 20 h. The cellular content of GSH was 1.70 +/- .02 micrograms GSH/micrograms PO4 in MEM alone and 0.540 +/- .02 micrograms GSH/micrograms PO4 in MEM + BSO. Furthermore, the GSH content in BLECs after 20 h of exposure to Gal was 0.960 +/- .01 microgram GSH/microgram PO4 but decreased to 0.110 +/- .01 microgram GSH/microgram PO4 in Gal + BSO.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anatomy, Texas College of Osteopathic Medicine, Fort Worth.
authors.forename: P R
authors.initials: PR
authors.lastname: Cammarata
authors.forename: T
authors.initials: T
authors.lastname: Yorio
mesh_terms: D000449:Aldehyde Reductase / Q000378:metabolism; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology*; D019328:Buthionine Sulfoximine; D002417:Cattle; D002478:Cells, Cultured; D003470:Culture Media; D004789:Enzyme Activation; D004847:Epithelial Cells; D005690:Galactose / Q000494:pharmacology; D005978:Glutathione / Q000096:biosynthesis*; D007424:Intracellular Fluid / Q000378:metabolism; D007903:Lens Capsule, Crystalline / Q000201:enzymology* / Q000378:metabolism; D007908:Lens, Crystalline / Q000201:enzymology*; D008717:Methionine Sulfoximine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011108:Polymers / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*
chemical_list: D000963:Antimetabolites; D003470:Culture Media; D011108:Polymers; C024617:polyol; D008717:Methionine Sulfoximine; D019328:Buthionine Sulfoximine; D000449:Aldehyde Reductase; D011451:Prostaglandin-Endoperoxide Synthases; D005978:Glutathione; D005690:Galactose