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Biochem Pharmacol. 1994 Mar 2;47(5):914-7.

Expression of monomorphic and polymorphic N-acetyltransferases in human colon.

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Department of Pharmacology, University of Western Australia, Nedlands.


The metabolism of sulfamethazine (SMZ) and p-aminobenzoic acid (PABA) by N-acetyltransferase (NAT) was measured in human colorectal cytosols from 12 slow and 11 rapid acetylators whose genotype was determined independently by a specific polymerase chain reaction. SMZ metabolism was significantly greater in the rapid than in the slow phenotype (192 +/- 22 versus 94 +/- 11 pmol N-acetylsulfamethazine/min/mg protein), while PABA metabolism was similar in both phenotypes (23.7 +/- 4.4 versus 23.0 +/- 3.9 nmol N-acetyl-p-aminobenzoic acid/min/mg protein). Both monomorphic and polymorphic NAT mRNAs were detected by the polymerase chain reaction in the colorectal mucosa of most samples. The finding that polymorphic NAT is expressed in a phenotype-dependent manner in colorectal mucosa indicates that this tissue has the capacity to participate in local bioactivation of dietary and environmental aryl- or heterocyclic amine carcinogens and may explain, in part, the phenotype-dependent occurrence of colorectal cancer.

[Indexed for MEDLINE]

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