DRUG ACETYLATION--BIOCHEMICAL AND MOLECULAR STUDIES

药物代谢中的遗传决定的差异可以影响 特异质药物毒性的风险。 鉴定这些代谢产物 差异可以提供对这些疾病发病机制的理解， 毒性反应，并可能有助于预防。 一口井- 人类特有的药物遗传学缺陷涉及缺乏 胞质芳胺N-乙酰转移酶（NAT）。 NAT缺陷已被 在人类中与药物毒性风险增加相关， 磺胺类、普鲁卡因胺、肼苯哒嗪和异烟肼。 狗是 磺胺类药物超敏反应的唯一自然发生模型， 人类 此外，狗在NAT中有一个定义不明确的缺陷 活动 因此，这些研究的具体目标是 表征犬细胞溶质芳胺N-乙酰化的这种缺陷， 为了比较的生化性质，分子基础，和患病率， 这种缺陷在人类中的描述，并描述的作用， 另一种微粒体乙酰化途径。 最初，南 犬基因组DNA印迹和PCR扩增将用于 筛选犬NAT基因，然后对犬进行Western blot分析。 肝胞液NAT蛋白。 北方印迹，DNA测序，和 如果鉴定出犬NAT基因，则将进行基因表达。 如果没有发现犬类基因，与狗有关的食肉动物也将被 筛选NAT基因的存在，以确定进化 基因缺失的本质 犬微粒体中的体外酶测定， HPLC检测将用于表征替代乙酰化 途径。

Genetically determined differences in drug metabolism can influence the risk of idiosyncratic drug toxicity. Identification of these metabolic differences can provide an understanding of the pathogenesis of these toxic reactions and may contribute to their prevention. One well- characterized pharmacogenetic defect in humans involves a deficiency of cytosolic arylamine N-acetyltransferase (NAT). NAT deficiency has been associated in humans with increased risk of toxicity from drugs such as sulfonamides, procainamide, hydralazine, and isoniazid. The dog is the only naturally occurring model for sulfonamide hypersensitivity in humans. In addition, the dog has a poorly defined defect in NAT activity. Therefore, the specific aims of these studies are to characterize this defect in cytosolic arylamine N-acetylation in dogs, to compare the biochemical nature, molecular basis, and prevalence of this defect to that described in humans, and to characterize the role of an alternative microsomal acetylation pathway. Initially, Southern blotting and PCR amplification of canine genomic DNA will be use to screen for canineNAT genes, followed by Western blot analysis of canine hepatic cytosol for NAT protein. Northern blotting, DNA sequencing, and gene expression will be pursued if canine NAT gene(s) are identified. If no canine genes are found, carnivores related to dogs will also be screened for the presence of NAT genes to determine the evolutionary nature of gene loss. In vitro enzymatic assays in canine microsomes and HPLC detection will be used to characterize alternative acetylation pathways.