Nijhout H F
J Exp Biol. 1975 Feb;62(1):221-30. doi: 10.1242/jeb.62.1.221.
Caterpillars of Manduca sexta use two distinct transport mechanisms for the excretion of dyes. One pump (Type A) has a high affinity for acid (anionic) dyes and occurs in the midgut and medial Malpighian tubules. Acid dyes accumulate rapidly in the lumen of the midgut while the Malpighian tubules appear to play only a minor role in the excretion of these dyes. The other pump (Type B) excretes basic (cationic) dyes and is located primarily in the proximal Malpighian tubules. Evidence is presented that hippuric acid competes with acid dyes for excretion by both midgut and Malpighian tubules. After the final-instar larva purges its gut the ability of the midgut and Malpighian tubules to excrete dyes gradually decreases. Sixty hours after the purge only the Malpighian tubules retain some dye excreting activity.
烟草天蛾毛虫利用两种不同的转运机制来排泄染料。一种泵（A型）对酸性（阴离子）染料具有高亲和力，存在于中肠和中肾管。酸性染料在中肠腔中迅速积累，而中肾管在这些染料的排泄中似乎只起次要作用。另一种泵（B型）排泄碱性（阳离子）染料，主要位于近端中肾管。有证据表明，马尿酸与酸性染料竞争中肠和中肾管的排泄。末龄幼虫排空肠道后，中肠和中肾管排泄染料的能力逐渐下降。排空60小时后，只有中肾管保留一些染料排泄活性。
