title: Urinary excretion of orally administered oxalic acid in MYRJ 45-treated NMRI mice.
abstract: Polyoxyethylene(8)stearate (MYRJ 45) has been shown to cause bladder tumours in chronic feeding studies. During this study the effects of dietary MYRJ 45 on the urinary excretion of dietary oxalic acid were tested. Male NMRI mice were gradually adapted to 20% MYRJ 45 in their diet. The animals were then dosed, after a 6 h fast, with 2 microCi of [U-14C]oxalic acid either with 1 ml of water or 1 ml of 20% MYRJ 45 in water. The urinary and faecal excretion of the label were determined using the combustion method coupled with liquid scintillation counting. MYRJ 45 was observed to increase significantly the urinary absorption of 14C in male NMRI mice when compared to control mice dosed with oxalic acid and water. The increase was observed both in MYRJ 45-pretreated mice receiving the label with MYRJ 45 or with water and in control mice receiving the label in a 20% MYRJ 45 water solution. The result indicates that dietary MYRJ 45 significantly increases the urinary excretion of dietary oxalic acid in male NMRI mice. This increase may contribute to the bladder tumour formation by facilitating calcium oxalate crystalluria with potential bladder wall irritating effect in mice.
mesh_terms: D000818:Animals; D004032:Diet; D005503:Food Additives / Q000633:toxicity*; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D051379:Mice; D010070:Oxalates / Q000008:administration & dosage / Q000652:urine*; D019815:Oxalic Acid; D011092:Polyethylene Glycols / Q000633:toxicity*
chemical_list: D005503:Food Additives; D010070:Oxalates; D011092:Polyethylene Glycols; C009314:polyethylene glycol monostearate; D019815:Oxalic Acid