title: Effect of PCB (polychlorobiphenyls) on on L-ascorbic acid, pyridoxal phosphate and riboflavin contents in various organs and on hepatic metabolism of L-ascorbic acid in the rat.
abstract: Effects of continuous oral administration of PCB (polychlorobiphenyls, 10-100 mg/kg/day, 4 weeks) on tissue levels of L-ascorbic acid (vitamin C), pyridoxal phosphate and riboflavin (vitamin B2) in various organs and on hepatic metabolism of L-ascorbic acid were examined in male Wistar rats weighing 150-250 g. Riboflavin contents in the liver, kidney, brain, heart and testis were not altered by PCB treatments, whereas the hepatic level of pyridoxal phosphate, a biologically active form of vitamin B6, was significantly reduced by PCB administration. Under the same experimental conditions, L-ascorbic acid contents in the liver, kidney, lung and testis showed a significant increase. Histochemical studied revealed that in the adrenal gland, increase of L-ascorbic acid was localized in the fasciculate and reticular zones of cortex, respectively. It was found that increase of L-ascorbic acid in the liver is caused predominantly by activation of biosynthesis at the steps of galactose to D-glucuronic acid and is not due to changes in the catabolic processes of L-ascorbic acid per se. Possible significance of these changes in tissue levels and/or metabolism of vitamins in the occurrence of PCB intoxication is briefly discussed.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001205:Ascorbic Acid / Q000032:analysis / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005690:Galactose / Q000378:metabolism; D005965:Glucuronates / Q000096:biosynthesis; D008099:Liver / Q000378:metabolism*; D008297:Male; D011078:Polychlorinated Biphenyls / Q000494:pharmacology* / Q000633:toxicity; D011732:Pyridoxal Phosphate / Q000032:analysis*; D051381:Rats; D012256:Riboflavin / Q000032:analysis*; D014018:Tissue Distribution
chemical_list: D005965:Glucuronates; D011732:Pyridoxal Phosphate; D011078:Polychlorinated Biphenyls; D001205:Ascorbic Acid; D012256:Riboflavin; D005690:Galactose