In:
American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 278, No. 1 ( 2000-01-01), p. E171-E176
Abstract:
l-2-Oxothiazolidine-4-carboxylic acid (OTZ), a 5-oxoproline analog, is metabolized by 5-oxoprolinase and converted to cysteine, the rate-limiting amino acid for GSH synthesis, with the release of CO 2 . [ 13 C]OTZ (1.5 mg/kg) was used in 12 healthy men and women (ages 23–73 yr) to indirectly assess precursor mobilization for GSH synthesis when stores were reduced by 2 g acetaminophen. Expired breath samples were analyzed for 13 CO 2 , and results were analyzed using noncompartmental and two-compartment open minimal models. Results show an increase in 13 C excretion (higher OTZ hydrolysis) when GSH stores were reduced and 5-oxoprolinase substrate utilization patterns, consequently, were altered ( P 〈 0.01). A metabolic rate index (MRI) of the OTZ probe was found to be significantly higher after reduction of GSH content by acetaminophen ( P 〈 0.05). The difference in adaptive capacity (difference between control and postacetaminophen metabolic rate indexes) was two times as large in the young than the old subjects ( P 〈 0.01). These data support the use of [ 13 C]OTZ as a probe to identify individuals who may be at risk for low GSH stores or who have an impaired capacity to synthesize GSH.
Type of Medium:
Online Resource
ISSN:
0193-1849
,
1522-1555
DOI:
10.1152/ajpendo.2000.278.1.E171
Language:
English
Publisher:
American Physiological Society
Publication Date:
2000
detail.hit.zdb_id:
1477331-4
SSG:
12
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