Open AccessLong‐term patterns of urinary pyroglutamic acid in healthy humans
Author(s) -
Lord Richard S.
Publication year - 2016
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12706
Subject(s) - pyroglutamic acid , creatinine , glutathione , urinary system , menstrual cycle , endocrinology , medicine , oxidative stress , physiology , chemistry , amino acid , biochemistry , hormone , enzyme
An investigation of human biological variation in urinary organic acids, including pyroglutamic acid along with 39 other compounds, was previously reported in which levels were determined for 8 weeks in healthy adult subjects. Here, unique, 4‐week‐long physiological trends for one of those compounds, pyroglutamic acid ( PGA ), are reported. When PGA levels for an individual rose above 40 μ g/mg creatinine, 4‐week downward progressions occurred until levels reached values near 15 μ g/mg creatinine and the pattern was reversed when levels for an individual were below that level in the early weeks of the study. The pattern was especially prominent among 8 of the 13 menstruating female subjects suggesting a possible association with metabolic stress of the menstrual cycle. However, it also appeared in 3 of the 8 male subjects where other sources of metabolic stress may be present. The menstrual association is consistent with estrogen‐mediated increase in oxidative stress. Since PGA is linked to glutathione turnover, the consistency of extreme values across all individuals displaying the pattern indicates that 15 and 40 μ g/mg creatinine may represent limits that trigger shifts in sulfur amino acid metabolism. This is the first observation of approximate month‐long cyclic responses in a glutathione‐related urinary marker in humans.