title: Skeletal muscles express the xenobiotic-metabolizing enzyme arylamine N-acetyltransferase.
abstract: The human arylamine N-acetyltransferases (NATs) NAT1 and NAT2 are enzymes responsible for the acetylation of many arylamines and hydrazines, thereby playing an important role in both detoxification and activation of many drugs and carcinogens. Both enzymes show polymorphisms but exhibit key differences in substrate selectivity and tissue expression. In the present study, reverse transcriptase-PCR, Western blotting, and immunohistochemistry were used to investigate the expression of the NATs in human skeletal muscle. Despite the presence of its mRNA, NAT2 enzyme level was below the limit of detection. In contrast, both NAT1 mRNA and enzyme were readily detected in fetal, newborn, and adult muscles. In addition, punctate cytoplasmic and perinuclear NAT1 immunostaining was observed in all tissue sections, the staining being more intense in the fetal tissue. High expression of NAT1 enzyme in fetal muscle was also suggested by Western blotting. Because skeletal muscle accounts for a large proportion of body mass, muscle NAT1 expression may contribute significantly to the total activity in the body. These results further support the involvement of skeletal muscle in the metabolism of xenobiotics.
authors.affiliation: CNRS-UMR7000, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodrigues-Lima
authors.forename: Racquel N
authors.initials: RN
authors.lastname: Cooper
authors.forename: Bertrand
authors.initials: B
authors.lastname: Goudeau
authors.forename: Noureddine
authors.initials: N
authors.lastname: Atmane
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Chamagne
authors.forename: Gillian
authors.initials: G
authors.lastname: Butler-Browne
authors.forename: Edith
authors.initials: E
authors.lastname: Sim
authors.forename: Patrick
authors.initials: P
authors.lastname: Vicart
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Dupret
mesh_terms: D000328:Adult; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005333:Fetus / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D007527:Isoenzymes / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015262:Xenobiotics / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D015262:Xenobiotics; D001191:Arylamine N-Acetyltransferase; C089384:N-acetyltransferase 1; C478900:NAT2 protein, human