Leaf C D, Wishnok J S, Tannenbaum S R
Division of Toxicology, Massachusetts Institute of Technology, Cambridge 02139.
Cancer Surv. 1989;8(2):323-34.
Endogenous formation of N-nitroso compounds has been demonstrated in both humans and experimental animals. The extent of this process has been estimated by measurement of urinary N-nitrosoproline and has been shown to be modulated by dietary precursors and inhibitors. It is now also recognized that other (non-gastric) pathways of endogenous nitrosation, including those catalysed by bacteria and mammalian cells, may exist. The mammalian cell catalysed pathway utilizes arginine as a precursor for the nitrosating agent and may occur in macrophages or endothelial cells. The estimated contribution of this pathway to normal basal endogenous nitrosation is approximately 20 nmol of N-nitrosoproline/day.
在人类和实验动物中均已证实存在内源性N-亚硝基化合物的形成。这一过程的程度已通过测量尿中的N-亚硝基脯氨酸来估计，并且已表明其受到膳食前体和抑制剂的调节。现在人们还认识到，可能存在其他（非胃的）内源性亚硝化途径，包括由细菌和哺乳动物细胞催化的途径。哺乳动物细胞催化途径利用精氨酸作为亚硝化剂的前体，可能发生在巨噬细胞或内皮细胞中。该途径对正常基础内源性亚硝化的估计贡献约为每天20 nmol的N-亚硝基脯氨酸。
