Studies of Sulfur Metabolism in Humans

Study Overview
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Brief Summary
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The study test whether the NSAID allosteric site of human sulfotransferase 1A1 (SULT1A1) is operative in humans. The study will test the effects of mefenamic acid (MEF) on the sulfonation of acetaminophen (APAP, a SULT1A1 specific substrate) and dehydroepiandrosterone (DHEA, a SULT2A1 substrate). If the allosteric site is active in vivo, MEF is predicted to result in a decrease in sulfonation of APAP (MEF inhibits SULT with high affinity (Ki = 23 nM), and to have no effect on sulfonation of the DHEA (MEF has little or no effect on SULT2A1 activity).

Detailed Description
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No patient registries associated with this study. A single, therapeutic dose of acetaminophen (APAP, 1.0 g)) or dehydroepiandrosterone (DHEA, 75 mg) is taken orally (with 375 ml of water) either alone or simultaneously with a single, oral, therapeutic dose of mefenamic acid (MEF, 0.75 g). In total, 5 experiments will be performed: 1, APAP alone; 2, DHEA alone; 3, MEF alone; 4, APAP + MEF; and 5, DHEA + MEF. Each experiment will be performed in duplicate. Compounds will be taken prior to eating breakfast. One hour later, the patient has a light breakfast (Cheerios and milk, and a cup of coffee) and eats normally thereafter. Urine samples are collected at 15', 30', 1 h, 2h, 3h, 4h, 5 h, 6h, 7h, 8h, 9h, 10h, 11h, and 12h intervals following dosing. The study subject will attempt to completely empty their bladder at each urine-collection time point. The samples are weighed. A 10 ml aliquot is taken from each time point and the aliquots are stored at -20 °C. Samples (0.5 ml) are then transferred to nuclear magnetic resonance (NMR) tubes and NMR spectra are taken to assess drug metabolites in urine. Proton NMR will be performed using the 600 MHz instrument in the Einstein facility.

Official Title
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Allosteric Regulation of Cytosolic Sulfotransferases in Humans

Conditions
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Metabolic Side Effects of Drugs

Intervention / Treatment
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* Drug: SULT Allosteric Inhibition


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Gender - one male Age - 61 y.o. Healthy Agreed to sign the consent form Exclusion criteria: ● None

Ages Eligible for Study
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Minimum Age: 61 Years
Maximum Age: 61 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: This study will involve only a single individual.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SULT Allosteric Inhibition<br>A single, therapeutic dose of acetaminophen (1.0 g)) or dehydroepiandrosterone (75 mg) is taken orally (with 375 ml of water) either alone or simultaneously with a single, oral, therapeutic dose of mefenamic acid (0.75 g). | Drug: SULT Allosteric Inhibition<br>* A single, therapeutic dose of acetaminophen (APAP, 1.0 g)) or dehydroepiandrosterone (DHEA, 75 mg) is taken orally (with 375 ml of water) either alone or simultaneously with a single, oral, therapeutic dose of mefenamic acid (MEF, 0.75 g). In total, 5 experiments will be performed. Each experiment is performed in duplicate. Compounds are taken prior to eating breakfast. One hour later, the patient has a light breakfast and eats normally thereafter. Urine samples are collected at 15', 30', 1 h, 2h, 3h, 4h, 5 h, 6h, 7h, 8h, 9h, 10h, 11h, and 12h intervals following dosing. The samples are weighed. A 10 ml aliquot is taken from each time point and the aliquots are stored at -20 °C. Samples (0.5 ml) are then transferred to NMR tubes spectra are taken to assess drug metabolites in urine.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acetaminophen and Dehydroepiandrosterone Conjugates | Proton NMR Signals will be used to quantitate conjugates of acetaminophen and dehydroepiandrosterone in urine. | 15min, 30min, 1hr, 2hr, 3hr, 4hr, 5hr, 6hr, 7hr, 8hr, 9hr, 10hr, 11hr, and 12hr following administration. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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sulfotransferase, metabolism, acetaminophen, dehydroepiandrosterone, mefenamic acid, allostery