title: Plasma B-6 vitamer changes following a 50-km ultra-marathon.
abstract: The purpose of this study was to measure plasma B-6 vitamers, and other factors which may affect the plasma concentrations of these vitamers under extreme physical conditions. Blood samples were drawn from 8 men and 3 women (43.7 +/- 8.6 years) 30 min prior to the start of a 50-km ultramarathon race (pre), and at 5 (PST) and 60 (PST60) min post race. HPLC was used to measure plasma pyridoxal 5O-phosphate (PLP), pyridoxal (PL), pyridoxine (PN), and 4-pyridoxic acid (4-PA). Plasma glucose, albumin, lactate, and alkaline phosphatase activity, as well as hematocrit, and hemoglobin levels were measured. Food and liquid intake was assessed during the run. There was a significant (p <.001) decrease in the plasma PLP concentration between pre and PST, with a mean decrease of 12.9 +/- 8.8 nmol/L (31% decrease). At PST60, there was a further decrease in plasma PLP concentration bringing the total decrease to 17.9 nmol/L (44%). The plasma TB6 concentration also decreased after the run, but the mean decrease was only 13.5 nmol/L (pre to PST60). PL increased 25% after the run, and did not change further at PST60. The mean plasma 4-PA concentration increased 21% post run and decreased to just below the pre-run value 1 hr post race. The plasma PLP decrease measured in the current study is not consistent with what has previously been reported during shorter length endurance studies.
authors.affiliation: Department of Nutrition and Food Management, Oregon State University, Corvallis, OR 97331-5103, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Leonard
authors.forename: J E
authors.initials: JE
authors.lastname: Leklem
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D010807:Physical Endurance / Q000502:physiology*; D010953:Plasma Volume / Q000502:physiology; D011732:Pyridoxal Phosphate / Q000097:blood; D011736:Pyridoxine / Q000031:analogs & derivatives* / Q000097:blood* / Q000378:metabolism; D012420:Running / Q000502:physiology*; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D011732:Pyridoxal Phosphate; D011736:Pyridoxine