title: Inhibition of calcium oxalate monohydrate (COM) crystal growth by pyrophosphate, citrate and rat urine.
abstract: An assay system for the measurement of the rate of Calcium Oxalate Monohydrate (COM) seed crystal growth in a metastable solution of calcium chloride and sodium oxalate containing traces of 14C-oxalic acid was used to assess the inhibitory activity of pyrophosphate (10(-5) M-10(-4) M), citrate (10(-4) M-10(-3) M) and urines of normal and pyridoxine deficient rats. Both pyrophosphate and citrate were strong inhibitors of COM crystal growth and caused a 50% decrease in crystal growth rate at 1.50 X 10(-5) M and 2.85 X 10(-4) M respectively. Normal rat urine strongly inhibited the COM crystal growth, while pyridoxine deficient animals showed a significant (p less than 0.01) decrease in mean inhibitory activity as compared to pair-fed controls. A lowered urinary inhibitory potential accompanied with hyperoxaluria and hypercalciuria, which is known to be associated with pyridoxine deficiency, may be a contributory risk of calcium oxalate crystallization and stone formation.
mesh_terms: D000818:Animals; D002122:Calcium Chloride; D002129:Calcium Oxalate; D002951:Citrates / Q000494:pharmacology*; D019343:Citric Acid; D003460:Crystallization; D011756:Diphosphates / Q000494:pharmacology*; D008297:Male; D010070:Oxalates; D019815:Oxalic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D012996:Solutions; D014545:Urinary Calculi / Q000209:etiology / Q000652:urine; D014556:Urine / Q000502:physiology*; D026681:Vitamin B 6 Deficiency / Q000652:urine
chemical_list: D002951:Citrates; D011756:Diphosphates; D010070:Oxalates; D012996:Solutions; D002129:Calcium Oxalate; D019343:Citric Acid; D019815:Oxalic Acid; D002122:Calcium Chloride