This study was designed to evaluate the effect of glucose on plasma pyridoxal 5'-
phosphate (PLP) concentration. The objective was to determine whether there was a
negative relationship between glucose ingestion and plasma PLP concentration and to
evaluate the possible mechanism of decreased PLP after acute glucose ingestion.
Seven healthy subjects (three males and four females) completed the oral glucose
tolerance test (OGTT) on three separate occasions over a period of three weeks. Each
week, subjects ingested the assigned solutions (a water solution with artificial sweetener
equivalent to 25g glucose, a 25g glucose or a 75g glucose load) in a randomized order.
Plasma PLP, pyridoxal (PL), 4-pyridoxic acid (4-PA), pyridoxine (PN), glucose, insulin,
alkaline phosphatase (AP) activity and red blood cell PLP concentrations were measured
at 0 (fasting) (TO), 1 (T1), 2 (T2) and 3 (T3) hours.
The mean vitamin B-6 intake based on two 3-day dietary records was 1.57 ± 0.34
mg/day. All subjects had normal glucose tolerance. There were gender differences
among the three solutions. Both the water solution and the 75g glucose load showed a significant decrease in the mean plasma PLP concentration was observed at T3 for males
and at T2 for females (p<0.05). An overall mean decrease of 20% (9nmol/L) and 15% (7
nmol/L) was observed for males and females, respectively, after the 75g glucose load.
The 25g glucose load resulted in a lower decrease in the mean plasma PLP concentration
at each time point compared with the 75g glucose load, but no significant difference was
found in the level of decrease between the two glucose loads.
Both genders had a non-significant increase in the mean plasma PL and PN
concentrations for the three solutions. Mean plasma 4-PA concentration was decreased at
T1 with the three solutions. There was no significant change in the plasma AP activity at
any time points after the three solutions. In addition, no significant increase in mean red
blood cell PLP concentration was observed at all time points after the three solutions.
This study found a negative relationship between glucose ingestion and plasma PLP
concentration. However, it did not provide clear evidence for the hypothesized
mechanism of the decreased plasma PLP concentration after acute glucose load. Further
studies are required to determine the mechanism by which glucose decreases plasma PLP
concentration. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26554 |
| Date | 11 January 2000 |
| Creators | Huang, Ying-Hui |
| Contributors | Leklem, James E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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