title: Captopril methylation in human liver and kidney: interindividual variability.
abstract: 1. The methylation of captopril was studied in the microsomal fraction obtained from 87 specimens of human liver and 70 specimens of human renal cortex. 2. The rate captopril methylation ranged over one order of magnitude in the liver and kidney. In the human liver, the mean (+/- SD) rate of captopril methylation (pmol/min/mg) was significantly (p < 0.001) greater in women (199 +/- 97) than in men (126 +/- 88), whereas in the kidney no sex-difference was observed, and the mean (+/- SD) of all cases was 47 +/- 23 pmol/min/mg. 3. In the kidney, the statistical analysis revealed the presence of two subgroups in the rate of captopril methylation and their mean (+/- SD) estimates were 42.5 +/- 13.9 and 90.3 +/- 12.0 pmol/min/mg (p < 0.05). Of the population, 84% fell in the former and the remaining 16% in the latter subgroup. 4. Captopril is mainly eliminated by metabolism and its bioavailability is 65%. Methylation is one of the metabolic routes of captopril and its variability may contribute, to some extent, to modulate the intracellular concentration of this drug.
authors.affiliation: Department of Biomedicine, Medical School, University of Pisa, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Ferroni
authors.forename: P C
authors.initials: PC
authors.lastname: Giulianotti
authors.forename: A
authors.initials: A
authors.lastname: Pietrabissa
authors.forename: F
authors.initials: F
authors.lastname: Mosca
authors.forename: R
authors.initials: R
authors.lastname: Gomeni
authors.forename: G M
authors.initials: GM
authors.lastname: Pacifici
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000378:metabolism / Q000494:pharmacology; D002216:Captopril / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008745:Methylation; D008875:Middle Aged; D015233:Models, Statistical; D012737:Sex Factors
chemical_list: D000959:Antihypertensive Agents; D002216:Captopril