Tissue Distribution and Developmental Changes in Detoxication Enzyme Activities in the Migratory Grasshopper, Melanoplus sanguinipes (Acrididae)

Abstract

Cytochrome P450 and cytochrome c reductase, glutathione S-transferase, and general esterase activities were determined in a variety of tissues for adult migratory grasshoppers, Melanoplus sanguinipes. On a per tissue basis, gastric ceca had the highest activities of all detoxication enzymes investigated. In terms of specific activity, glutathione S-transferase was highest in the midgut, cytochrome P450 was highest in the Malpighian tubules, general esterase was highest in the gastric ceca, and cytochrome c reductase was equally highest in the gastric ceca and the midgut. Cytochrome P450 levels and cytochrome c reductase activities were also determined in third, fourth, and fifth nymphal instars, as well as different ages of the adult stage. On a per milligram protein basis, third instar nymphs had the highest levels of cytochrome P450 and cytochrome c reductase activity. On a per tissue basis, cytochrome P450 and reductase activities were low on the first day after molting in each stage, dramatically increased on the third day, and then decreased to a very low level on the last day of the instar. Beyond the second day, enzyme activities were present in substantial levels throughout the adult stage. Detoxicative enzyme activities in this species are compared to results reported for other acridids, and the tissue-specific patterns are compared with those of lepidopterans.