Metabolism of cytochrome P4503A substrates in vivo administered by the same route: Lack of correlation between alfentanil clearance and erythromycin breath test

1994 ◽  
Vol 56 (6) ◽  
pp. 608-614 ◽  
Author(s):  
Yuri Krivoruk ◽  
Mark T Kinirons ◽  
Alastair J J Wood ◽  
Margaret Wood
Keyword(s):  
Breath Test ◽  
Erythromycin Breath Test ◽  
Cytochrome P4503a

Characterization of cytochrome P450 2E1 activity by the [14C]nitrosodimethylamine breath test

1998 ◽  
Vol 76 (7-8) ◽  
pp. 756-763 ◽  
Author(s):  
Marie-Claude Bastien ◽  
Jean-Pierre Villeneuve
Keyword(s):  
Cytochrome P450 ◽  
Breath Test ◽  
Cytochrome P450 2E1 ◽  
Diallyl Sulfide ◽  
Aminopyrine Breath Test ◽  
Breath Tests ◽  
Erythromycin Breath Test ◽  
Cyp2e1 Activity

The objective of this study was to measure the rate of demethylation of nitrosodimethylamine in vivo in the rat and determine its value to assess CYP2E1 activity in intact animals. Nitrosodimethylamine labeled with 14C on both methyl groups was administered to rats and exhaled 14CO2 was collected during 2-3 h. The nitrosodimethylamine breath test was increased by inducers of CYP2E1, such as ethanol (+139%) and 4-methylpyrazole (+115%), and decreased by the inhibitor diallyl sulfide (-53%). In addition, the nitrosodimethylamine breath test was not changed significantly by inducers specific for other cytochrome P450 such as beta-naphthoflavone, dexamethasone, and phenobarbital. The specificity of the induction by 4-methylpyrazole and of the inhibition by diallyl sulfide for CYP2E1 was determined using the [14C]caffeine (CYP1A2), [14C]aminopyrine (CYP2C11), and [14C]erythromycin (CYP3A2) breath tests. 4-Methylpyrazole treatment caused a small increase of the caffeine (+33%) and aminopyrine (+9%) breath tests and no change of the erythromycin breath test. Diallyl sulfide treatment led to a small decrease of the caffeine breath test (-33%) and of the aminopyrine breath test (-13%) but a 23% increase of the erythromycin breath test. It is concluded that the [14C]nitrosodimethylamine breath test is useful to assess CYP2E1 activity in vivo in the rat.Key words: breath test, CYP2E1, nitrosodimethylamine.

Failure of erythromycin breath test to correlate with midazolam clearance as a probe of cytochrome P4503A*

1999 ◽  
Vol 66 (3) ◽  
pp. 224-231 ◽  
Author(s):  
Mark T. Kinirons ◽  
Diarmuid O'Shea ◽  
Richard B. Kim ◽  
John D. Groopman ◽  
Kenneth E. Thummel ◽  
...  
Keyword(s):  
Breath Test ◽  
Erythromycin Breath Test ◽  
Cytochrome P4503a

Concurrent Administration of the Erythromycin Breath Test (EBT) and Oral Midazolam as In Vivo Probes for CYP3A Activity

1999 ◽  
Vol 39 (12) ◽  
pp. 1212-1220 ◽  
Author(s):  
Jacqueline McCrea ◽  
Thomayant Prueksaritanont ◽  
Barry J. Gertz ◽  
Alexandra Carides ◽  
Lisa Gillen ◽  
...  
Keyword(s):  
Breath Test ◽  
Cyp3a Activity ◽  
Concurrent Administration ◽  
Oral Midazolam ◽  
Erythromycin Breath Test
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