Howells A J, Ryall R L
Biochem Genet. 1975 Apr;13(3-4):273-82. doi: 10.1007/BF00486022.
3-Hydroxykynurenine is virtually absent from st larvae but accumulates during adult development in the puparium. Over the period of adult emergence, the accumulated 3-hydroxykynurenine is excreted so that st adults contain none. Larvae of st fed on tryptophan-C-14 medium produce labeled 3-hydroxykynurenine, at a reduced rate, perhaps, compared to wild type. Xanthurenic acid levels in st pupae are similar to those in wild type. Thus the failure of st larvae to accumulate 8-hydroxykynurenine does not seem to be due either to an inability to synthesize this compound or to an excessive rate of its conversion to xanthurenic acid. Rather, it appears that the mechanism of 3-hydroxykynureneine storage during larval life is defective, so that this compound is excreted at an abnormally high rate. The inability of the pigment cells of the eyes of st to synthesize xanthommatin may result form a similar defect in their ability to take up or store 3-hydroxykynurenine.
3-羟基犬尿氨酸在黑腹果蝇（st）幼虫中几乎不存在，但在成虫发育期间于蛹壳中积累。在成虫羽化期间，积累的3-羟基犬尿氨酸会被排泄掉，因此黑腹果蝇成虫中不含该物质。以色氨酸-C-14培养基喂养的黑腹果蝇幼虫会产生标记的3-羟基犬尿氨酸，与野生型相比，其生成速率可能降低。黑腹果蝇蛹中的黄尿酸水平与野生型相似。因此，黑腹果蝇幼虫未能积累8-羟基犬尿氨酸，似乎既不是由于无法合成该化合物，也不是由于其转化为黄尿酸的速率过高。相反，似乎是幼虫期3-羟基犬尿氨酸的储存机制存在缺陷，导致该化合物以异常高的速率排泄。黑腹果蝇眼睛的色素细胞无法合成眼黄素，可能是由于它们摄取或储存3-羟基犬尿氨酸的能力存在类似缺陷。
