2,3-Dinor metabolites of thromboxane A2 and prostacyclin in urine from healthy human subjects: diurnal variation and relation to 24h excretion.
1. Urinary levels of the 2,3-dinor metabolites of thromboxane A2 (2,3-dinor-thromboxane A2, Tx-M) and prostacyclin (2,3-dinor-6-keto-prostaglandin F1 alpha, PGI-M) are frequently analysed as indices of platelet and endothelial activity and interaction in vivo. Despite this, little is known about the possible diurnal variations in urinary Tx-M and PGI-M in healthy human subjects, and how the urinary levels of Tx-M and PGI-M in single samples reflect their respective 24 h excretion rates. We addressed this by determining Tx-M, PGI-M and creatinine in consecutive portions of urine collected during 24 h in 15 healthy non-smoking subjects. 2. The total 24 h excretion of Tx-M and PGI-M did not differ between men (223 +/- 31 and 132 +/- 27 ng, respectively) and women (215 +/- 44 and 127 +/- 29 ng, respectively). Neither the excretion of Tx-M nor that of PGI-M displayed any significant diurnal variation. 3. The excretion of Tx-M during a 3 h period and the Tx-M/creatinine ratio in a urine sample accurately reflected the 24 h excretion of Tx-M (correlation coefficient ranges 0.74-0.94 and 0.74-0.86, respectively). The excretion of PGI-M during a 3 h period and the PGI-M/creatinine ratio in a urinary sample were accurate measures of 24 h excretion of PGI-M (correlation coefficient ranges 0.76-0.94 and 0.72-0.83, respectively). Urinary Tx-M and PGI-M expressed as simple concentrations were poor indices of their respective 24 h excretion. 4. We conclude that time-related excretions of Tx-M and PGI-M may be the best indices ex vivo of the cardiovascular formation of thromboxane A2 and prostacyclin, but that urinary creatinine-related concentrations of Tx-M and PGI-M in a urine sample are accurate measures as well.
Wennmalm
A
A
Department of Clinical Physiology, Gothenburg University, Sahlgrenska Hospital, Sweden.
Benthin
G
G
Granström
E F
EF
Persson
L
L
Winell
S
S
D015121:6-Ketoprostaglandin F1 alpha / Q000031:analogs & derivatives / Q000652:urine; D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D003404:Creatinine / Q000652:urine; D011464:Epoprostenol / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013928:Thromboxane A2 / Q000652:urine*; D013997:Time Factors
D013928:Thromboxane A2; D015121:6-Ketoprostaglandin F1 alpha; C028290:2,3-dinor-6-ketoprostaglandin F1alpha; D003404:Creatinine; D011464:Epoprostenol