title: F(2)-isoprostane and prostaglandin F(2 alpha)metabolite excretion rate and day to day variation in healthy humans.
abstract: Isoprostanes are mainly formed in vivo by a non-enzymatic free radical catalysed oxidation of arachidonic acid. Studies have indicated that a major isoprostane, 8-iso-PGF(2 alpha)in plasma and urine is a reliable biomarker of oxidative stress. Prostaglandins are formed by enzymatic oxidation of arachidonic acid catalysed by cyclooxygenase (COX). 15-Keto-dihydro-PGF(2 alpha), a major metabolite of prostaglandin F(2 alpha)in plasma, and also found in urine, is considered to be a useful biomarker of inflammation. To investigate the excretion pattern and day to day variation of 8-iso-PGF(2 alpha)and 15-keto-dihydro-PGF(2 alpha)in healthy individuals, morning urine samples were collected from 13 volunteers on 10 successive days. The samples were analysed for free 8-iso-PGF(2 alpha)and 15-keto-dihydro-PGF(2 alpha)by radioimmunoassay. The mean excretion rate of 8-iso-PGF(2 alpha)was 0.27+/-0.11 nmol/mmol creatinine (mean+/-SD, n=13) and the coefficient of variation was 42% during the 10 days. The mean excretion rate of 15-keto-dihydro-PGF(2 alpha)was 0.46+/-0.19 nmol/mmol creatinine, giving a coefficient of variation of 41%. The mean values of 8-iso-PGF(2 alpha)were significantly correlated with the mean values of 15-keto-dihydro-PGF(2 alpha)(r=0.68, P=0.01). In conclusion, day to day biological variation in urinary excretion rate of 8-iso-PGF(2 alpha)and 15-keto-dihydro-PGF(2 alpha)should be taken into account in evaluating a clinical study unless a large increase or decrease of these parameters has been obtained.
authors.affiliation: Unit of Clinical Nutrition Research, Uppsala University, Sweden
authors.forename: J
authors.initials: J
authors.lastname: Helmersson
authors.forename: S
authors.initials: S
authors.lastname: Basu
mesh_terms: D000328:Adult; D003404:Creatinine / Q000652:urine; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000652:urine*; D028441:F2-Isoprostanes / Q000378:metabolism* / Q000652:urine*; D005260:Female; D006801:Humans; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D028441:F2-Isoprostanes; C075750:8-epi-prostaglandin F2alpha; C026528:15-ketoprostaglandin F2alpha; D003404:Creatinine; D015237:Dinoprost