title: Aging and vitamin B-6 depletion: effects on plasma pyridoxal-5'-phosphate and erythrocyte aspartate aminotransferase activity coefficients in rats.
abstract: Plasma pyridoxal-5'-phosphate (PLP) and erythrocyte aspartate aminotransferase activity coefficients were longitudinally determined in rats. Blood was obtained at weeks 0, 1, 2, 4, 6, 9, and 11 from rats initially aged 3 wk, 3 mo, 12 mo, and 23 mo (weeks 0, 1, 4, 6, and 9 only). The diet groups were ad libitum control (ALC), deficient (DEF), and pair-fed control (PF). Plasma PLP concentrations of controls were highest at 3 mo, intermediate at 3 wk and 12 mo, and lowest at 23 mo. When an additional group of 22-mo-old rats was fed a high-vitamin B-6 diet for 4 wk, their low baseline plasma PLP concentrations did not increase significantly. Plasma PLP decreased significantly within 1 wk and activity coefficients increased significantly by week 4 in all DEF rats. Depletion was most rapid and severe in the youngest DEF rats and least in 12-mo-old DEF rats. Mechanisms for the low plasma PLP control values and resistance to depletion in aged rats remain to be determined.
authors.affiliation: USDA Human Nutrition Research Center, Tufts University, Boston, MA 02111.
authors.forename: E F
authors.initials: EF
authors.lastname: Cochary
authors.forename: S N
authors.initials: SN
authors.lastname: Gershoff
authors.forename: J A
authors.initials: JA
authors.lastname: Sadowski
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood*; D001835:Body Weight; D002149:Energy Intake; D004912:Erythrocytes / Q000201:enzymology*; D008297:Male; D009752:Nutritional Status; D011732:Pyridoxal Phosphate / Q000097:blood; D011736:Pyridoxine / Q000097:blood; D051381:Rats; D011916:Rats, Inbred F344; D026681:Vitamin B 6 Deficiency / Q000201:enzymology / Q000209:etiology* / Q000378:metabolism
chemical_list: D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases; D011736:Pyridoxine