Frost S K, Bagnara J T
J Exp Zool. 1979 Sep;209(3):455-66. doi: 10.1002/jez.1402090311.
The enzyme, xanthine dehydrogenase (XDH), has been examined in Ambystoma tigrinum nebulosum with respect to its role in pigmentation. It now seems probable that the melanoid gene (m) either codes directly for XDH or is somehow intimately connected with the normal function of this enzyme. Inhibition of XDH using the drug, allopurinol, results in animals which appear to be phenocopies of melanoid mutants as described for the Mexican axolotl (Ambystoma mexicanum). The effects of allopurinol in terms of specific pigmentary alterations were examined, and a new method for analyzing heterogeneous extracts of skin pigments (e.g., purines and pteridines) is presented. The significance of the link between XDH and melanism is discussed with emphasis on possible mechanisms of pigment induction and general applicability to biological systems.
已对虎斑钝口螈（Ambystoma tigrinum nebulosum）中的黄嘌呤脱氢酶（XDH）进行了研究，以探讨其在色素沉着中的作用。现在看来，类黑素基因（m）要么直接编码XDH，要么以某种方式与该酶的正常功能密切相关。使用药物别嘌呤醇抑制XDH会导致动物出现类似墨西哥钝口螈（Ambystoma mexicanum）中描述的类黑素突变体的表型模拟。研究了别嘌呤醇在特定色素改变方面的作用，并提出了一种分析皮肤色素（如嘌呤和蝶啶）异质提取物的新方法。讨论了XDH与黑化之间联系的意义，重点在于色素诱导的可能机制以及对生物系统的普遍适用性。
