The effect of 2-aminofluorene (2-AF) on the toxicity of 2-aminoanthracene (2-AA) and 1,6-dinitropyrene (1,6-DNP) was studied in N-acetyltransferase-proficient V79-NHr1A2 cells genetically engineered for the expression of cytochrome P4501A2, and in wild-type V79-NH cells. 2-AA inhibited the growth of V79-NHr1A2 cells and induced the formation of micronuclei at concentrations of 0.1 to 1.0 microM...

Arylamine N-acetyltransferases (Nat) 1 and 2 catalyze the N-acetylation of aromatic amine and hydrazine drugs and carcinogens. After N-hydroxylation, they also catalyze the metabolic activation of N-hydroxy-arylamines via O-acetylation. Functional characterization of mouse Nat1 and Nat2 was investigated in an Nat2 knockout (KO) model and compared with the wild-type (WT) strain. Nat1- and Nat2-s...

Rhythmic activity of arylalkylamine N-acetyltransferase (AANAT) determines melatonin synthesis in rat pineal gland. The transcriptional regulation of AANAT involves the activating and inhibiting transcription factors of the cyclic AMP (cAMP)-signaling pathway, cAMP response element-binding protein and inducible cAMP early repressor (ICER), respectively. Activation of this pathway is centered ar...

Castrated male and intact female pigs were kept under natural photoperiodic and temperature conditions and were killed over a 24 h period in either May (under long days) or in December (under short days). Neither the pineal norepinephrine (NE) concentration nor the melatonin content rose at night; likewise, neither the activities of N-acetyltransferase (NAT) nor hydroxyindole-O-methyltransferas...

There are some suggestions that, in the pineal gland, serotonin acts not only as a precursor of melatonin but also plays a role in the modulation of the pineal biosynthetic activity. To corroborate this possible neuromodulatory role of 5-hydroxytryptamine (serotonin) (5-HT) on the pineal gland, the effects of two 5-HT(2) receptor agonists meta-chlorophenylpiperazine (m-CPP) and 1-(2, 5-dimethox...

Small laboratory animals have provided significant information about melatonin regulation, yet most of these organisms are nocturnal and regulate melatonin synthesis by mechanisms that diverge from those of humans. For example, in all rodents examined, melatonin secretion occurs with a time lag of several hours after the onset of darkness; in addition, arylalkylamine N-acetyltransferase (AANAT)...

Heparin acetyl-CoA:alpha-glucosaminide N-acetyltransferase (N-acetyltransferase, EC 2.3.1.78) is an integral lysosomal membrane protein containing 11 transmembrane domains, encoded by the HGSNAT gene. Deficiencies of N-acetyltransferase lead to mucopolysaccharidosis IIIC. We demonstrate that contrary to a previous report, the N-acetyltransferase signal peptide is co-translationally cleaved and ...

The clinical use of amifampridine phosphate for neuromuscular junction disorders is increasing. The metabolism of amifampridine occurs via polymorphic aryl N-acetyltransferase (NAT), yet its pharmacokinetic (PK) and safety profiles, as influenced by this enzyme system, have not been investigated. The objective of this study was to assess the effect of NAT phenotype and genotype on the PK and sa...

N-Acetyltransferase (NAT) is one of the major phase II enzymes involved in drug metabolism. Both species differences and polymorphism are observed in NAT expression. During the preclinical development of a novel selective androgen receptor modulator, S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethyl-phenyl)-propionamide (S4), we also observed species differences in S4 ...

Phosphinothricin (PPT) is the active ingredient in bialaphos, which specifically inhibits glutamine synthetase in land plants. We isolated a novel PPT-resistant gene from a soil bacterium, Nocardia sp., and characterized it. The encoded protein, consisting of 177 amino acids, showed significant similarity to bacterial N-acetyltransferases, and we originally designated the gene MAT (methionine s...