82091
document
Quantifications of the major urinary metabolite of the E prostaglandins by mass spectrometry : evaluation of the method 's application to clinical studies . Measurement of 7alpha-hydroxy-5,11-diketotetranoprostane-1,16-dioic acid , ( PGE-M ) , the major urinary metabolite of prostaglandin E1 and E2 in man provides a useful indicator to monitor prostaglandin biosynthesis . For quantitative analysis of this prostaglandin metabolite and the stable-isotope dilution techniqe of selected ion monitoring ( SIM ) is employed using gas-liquid chromatography-mass spectrometry . The preparation of the bis ( D3-methyloxime ) , bis-methyl ester of PGE-M containing a tritium tracer in position 2 which was used as internal standard for the SIM method is described . The synthesis of this internal standard includes the biosynthetic conversion of 11-hydroxy-9,15-diketoprostanoic acid to PGE-M by the rabbit . The intra-assay coefficient of variation of this SIM method ranged between 4.0 to 6.7 percent . The recovery of authentic , underivatized PGE-M added to urine was 93 +/- 3 % ( mean +/- SEM , n=17 ) . The levels of PGE-M excreted in urine were higher ( p less than 0.001 ) in males than in females ( 15.2 +/- 1.9 mug/24 hours ( n=24 ) and 3.3 +/- 0.3 mug/24 hours ( n=17 ) , respectively . These levels were in close agreement with values published previously . No significant difference in excretion of PGE-M between the sexes was observed in the pre-pubertal age-grou ( male : 2.9 +/- 0.8 mug/24 hours , n=5 ; female : 3.1 +/- 0.9 mug/24 hours , n=5 ) or in the age-group of 45-80 years ( male : 9.3 +/- 1.1 mug/24 hours , n=21 ; female : 7.3 +/- 0.9 mug/24 hours , n=12 ) . The amount of PGE-M excreted decreased significantly after administration of indomethacin or acetyl salicylic acid in therapeutic doses . The concomitant reduction of the urinary excretion of PGE-M ( 68 to 85 % decrease ) and prostaglandin E ( 73 to 100 % decrease ) after indomethacin treatment in each case ( n=8 ) is evidence that a diminished urinary PGE-M output reflects a decrease in prostaglandin E biosynthesis .
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Intervention_Physical
mass spectrometry
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Intervention_Physical
selected ion monitoring
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Intervention_Pharmacological
bis ( D3-methyloxime ) , bis-methyl ester of PGE-M
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Intervention_Pharmacological
indomethacin
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Intervention_Pharmacological
acetyl salicylic acid
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Intervention_Pharmacological
indomethacin
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Outcome_Physical
urinary metabolite of the E prostaglandins
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Outcome_Physical
levels of PGE-M excreted
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Participant_Sex
man
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Participant_Sex
males
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Participant_Sex
females
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Participant_Age
pre-pubertal age-grou
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Participant_Age
age-group of 45-80 years