Incomplete utilization of pyridoxine-beta-glucoside as vitamin B-6 in the rat.
This research was conducted to determine the bioavailability of 5'-O-(beta-D-glucopyranosyl) pyridoxine (PN-glucoside) during chronic administration in a depletion-repletion bioassay. PN-glucoside was found previously to constitute a major portion of the total vitamin B-6 in many foods of plant origin. Following a 14-d depletion period, rats were fed diets containing graded levels of either free pyridoxine (PN) or PN-glucoside for 17 d. Slope ratio analysis of dose-response curves, on the basis of growth and plasma pyridoxal 5-phosphate (PLP) concentration, indicated 10-34% utilization of PN-glucoside relative to the molar response to PN. Erythrocyte aspartate amino-transferase (AspAT) activity and urinary 4-pyridoxic acid concentration were lower and the stimulation of AspAT activity by exogenous PLP was greater for rats fed PN-glucoside than for those fed PN, which indicated reduced vitamin B-6 nutriture in response to PN-glucoside. A constant 7-9% of the ingested PN-glucoside was detected in urine in intact form at all dosage levels. These results provide further evidence of incomplete bioavailability of PN-glucoside and indicate that its extent of utilization is not influenced by its level of dietary intake.
Trumbo
P R
PR
Food Science and Human Nutrition Department, University of Florida, Gainesville 32611.
Gregory
J F
JF
Sartain
D B
DB
D000284:Administration, Oral; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001682:Biological Availability; D001835:Body Weight; D004912:Erythrocytes / Q000201:enzymology; D005960:Glucosides; D008297:Male; D011736:Pyridoxine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains
D005960:Glucosides; C022945:5'-O-(glucopyranosyl)pyridoxine; D001219:Aspartate Aminotransferases; D011736:Pyridoxine