Circadian rhythmicity of whole-blood glutathione in healthy subjects.
OBJECTIVE
Physiologic rhythms of antioxidants have been the subject of considerable interest in recent years. Physiologically, it is known that 24-h variability in whole-blood glutathione (GSH) could depend on various factors, such as meal composition, protein dietary content, meal-related hormonal modifications, and stress. Experiments were conducted to determine if the circadian variations previously observed in hepatic concentrations of reduced glutathione in animals also occurred in healthy volunteers.


METHODS
The circadian periodicity of whole-blood glutathione was explored. All parameters were measured enzymatically at 4-h intervals over a 24-h period.


RESULTS
Circadian rhythms were not found. The rhythms peak for glutathione content occurred at 9 h with a small peak at 21 h. The nadir occurred at 17 h and 1 h.


CONCLUSIONS
These data show that despite this wide distribution of glutathione throughout the day we could not find any significant intertime variability.
Valencia
E
E
Marin
A
A
Hardy
G
G
D000328:Adult; D002940:Circadian Rhythm; D003545:Cysteine / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D005978:Glutathione / Q000008:administration & dosage / Q000097:blood*; D006706:Homeostasis; D006801:Humans; D008297:Male; D008715:Methionine / Q000008:administration & dosage; D010084:Oxidation-Reduction
D004044:Dietary Proteins; D008715:Methionine; D005978:Glutathione; D003545:Cysteine