EFFECTS OF JUGLONE (5-HYDROXY-L,4-NAPHTHOQUINONE) ON MIDGUT MORPHOLOGY AND GLUTATHIONE STATUS IN SATURNIID MOTH LARVAE

Actias luna and Callosamia promethea larvae were fed birch foliage sup plemented with juglone (5-hydroxy-1,4-naphthoquinone) to determine whe ther juglone causes oxidative stress in midguts of these species. Jugl one is a substituent of walnut foliage. A. luna, but not C. promethea, thrives on walnut foliage, as well as birch foliage supplemented with juglone. After 2 and 3 days on juglone-containing diets, midgut sampl es from these animals were compared histologically and were analyzed f or GSH and GSSG content. C. promethea, but not A. luna, midguts reveal ed partial loss of epithelial structure. In contrast, GSH and GSSG did not change significantly in either species. In a separate experiment, live midgut explants from each species were cultured for 4 h in 0, 0. 05, and 0.25% juglone. In juglone-treated explants, GSSG increased 2.1 and 5.6-fold, respectively, for A. luna, and 1.6 and 2.7-fold, respec tively, for C. promethea. There was also a small dose-dependent decrea se in GSH in C. promethea, but not A. luna. Although histology indicat es that the midgut is a target of juglone toxicity in C. promethea, GS H analyses from either species do not support the expectation that cha nges in GSH/GSSG explain differences in susceptibility to juglone toxi city. (C) 1998 Elsevier Science Inc. All rights reserved.