The effect of oral contraceptives on the urinary excretion of
several methionine metabolites was determined in women before and
after they had received a 3-g dose of L-methionine. Nine women
between the ages of 20-29 years served as subjects: five had been
using a combination-type oral contraceptive for six months or more
(experimental group), and four had not been using these drugs
(control group). Cystathionine excretion by both groups before and
after the methionine loading was in the range reported for normal
female subjects who were not deficient in vitamin B₆ (Krishnaswamy,
1972; Shin and Linkswiler, 1974). Changes in urinary methionine
metabolites that were apparently produced by oral contraceptive
drugs are: (1) homocysteine was detected in the basal urine of three
of the oral contraceptive users. After methionine loading, it was
found in the urine of four of these subjects, two of whom excreted measurable quantities. In contrast, three of the control subjects
excreted traces of homocysteine only after methionine loading.
(2) The mean excretion of taurine by oral contraceptive users was
only one-tenth of that excreted by the control subjects.
The activity of erythrocyte glutamic oxaloacetic transaminase
(EGOT) before and after in vitro stimulation with added pyridoxal
phosphate was similar in both groups. Basal activity of erythrocyte
glutamic pyruvic transaminase (EGPT) was lower in oral contraceptive
users, although the mean values for both groups were within the
normal range reported by Miller et al. (1975) and Woodring and
Storvick (1970). The percent in vitro stimulation after addition of
pyridoxal phosphate was somewhat higher in oral contraceptive users,
but the difference was not statistically significant.
Thirteen free acidic and neutral amino acids (including metabolites
of the methionine pathway) were measured in the urine specimens.
The sum of the urinary excretion of these 13 amino acids was
significantly lower (p < 0.01) for oral contraceptive users than for
control subjects. However, total α-amino nitrogen excretion,
measured in the same urine specimens, was similar for both groups. / Graduation date: 1976
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26196 |
| Date | 27 May 1975 |
| Creators | Dow, Marjorie J. |
| Contributors | Miller, Lorraine T. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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