title: Vitamin B6 nutritional status in asthma: the effect of theophylline therapy on plasma pyridoxal-5'-phosphate and pyridoxal levels.
abstract: Plasma pyridoxal-5'-phosphate concentrations were significantly lower (p less than 0.001) in a group of 28 asthmatic women when compared to 33 controls. Plasma pyridoxal levels in the two groups were not different. Theophylline was administered to a group of 17 volunteers and resulted in large reductions in plasma pyridoxal-5'-phosphate levels, while plasma pyridoxal levels and urinary 4-pyridoxic acid excretion were unaffected by theophylline therapy. An in vitro study showed that theophylline did not interfere with the high performance liquid chromatography assay for pyridoxal-5'-phosphate, indicating that theophylline could affect liver metabolism of vitamin B6.
authors.affiliation: Department of Chemical Pathology, University of Pretoria, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: Delport
authors.forename: J B
authors.initials: JB
authors.lastname: Ubbink
authors.forename: W J
authors.initials: WJ
authors.lastname: Serfontein
authors.forename: P J
authors.initials: PJ
authors.lastname: Becker
authors.forename: L
authors.initials: L
authors.lastname: Walters
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D011730:Pyridoxal / Q000097:blood*; D011732:Pyridoxal Phosphate / Q000097:blood*; D011735:Pyridoxic Acid / Q000652:urine; D011736:Pyridoxine / Q000378:metabolism*; D013806:Theophylline / Q000627:therapeutic use*
chemical_list: D011730:Pyridoxal; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D013806:Theophylline; D011736:Pyridoxine