Serine transhydroxymethylase (STHM), a pyridoxal 5'-
phosphate requiring enzyme is indirectly involved in
pyrimidine deoxynucleotide metabolism. A decrease in the
activity of this enzyme could lead to altered deoxycytidine
(dC) metabolism. This study was undertaken to determine if
a vitamin B-6 deficiency affects dC metabolism. The effect
of a vitamin B-6 deficiency on the activity of STHM in
liver, thymus, spleen and bone marrow was examined. In
addition, the effect of a vitamin B-6 deficiency on urinary
excretion of dC was examined. The effect of a vitamin B-6
deficiency on the urinary excretion and tissue retention of
³H label from ip injected ³H-dC was monitored.
Rats were assigned in groups of six to one of four
treatment groups: ad libitum control (ALC), pair fed
control (PFC), ad libitum deficient (ALD) or meal fed
deficient (MFD). At the end of weeks 2 and 6, rats from
each treatment group received an ip injection of ³H-dC.
Urines were collected for 24 hours following the ip inhibited due to lack of cofactor, then dTMP levels would
fall. In an attempt to increase the concentration of dTMP,
enzymes active in the conversion of dC and dCMP to dUMP
would be expected to increase. Thus, dC salvage pathways
would increase and dC synthesis would decrease as metabolism
shifts toward production of deoxythymidine triphosphate
(dTTP). The result would be lower urinary dC excretion.
The present study was undertaken to explore the
relationship between vitamin B-6 and pyrimidine
deoxynucleotide metabolism. There were four hypothesis
tested: Vitamin B-6 deficient rats will excrete less
urinary dC than either ad libitum or pair fed controls;
vitamin B-6 deficient rats will excrete a lower percentage
of labeled dC in urine than control rats; vitamin B-6
deficient rats will incorporate less labeled dC into DNA
than control rats but may retain more label in tissues as dC
metabolites; activity of STHM from tissues of vitamin B-6
deficient rats will be lower than that from the control
rats. / Graduation date: 1990
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27249 |
| Date | 30 November 1989 |
| Creators | Jensen, Christine May |
| Contributors | Leklem, James E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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