Effects of deltamethrin on glucose catabolic pathways in the isolated fat body of adult male Locusta migratoria

The effects of various doses (non lethal, LD(15), LD(25), LD(50), LD(75)) of the pyrethroid insecticide deltamethrin were investigated on glucose catabolism pathways in the isolated fat body of starved 25-day-old male adult Locusta migratoria. Two methods of poisoning with deltamethrin were used. In the first case, the insecticide was injected into the locust in vivo and then the fat body was dissected either 30 min or 1hr after injection. The orientation of glucose with respect to its catabolic pathways was estimated in isolated fat body by means of radio-respirometric method using [1-C-14]glucose and [6-C-14]glucose. Deltamethrin reduced the relative participation of the pentose pathway, and this effect was maximal 1hr after insecticide treatment. Glucose degradation in the glycolysis Krebs cycle was increased only 30 min after treatment. Deltamethrin significantly modified the orientation of glucose between the catabolic pathways. In the second case, deltamethrin was added directly into the fat body incubation medium after its sampling in in vitro conditions. Labeled glucose was added either simultaneously or 30 min after the insecticide dose. In both cases, deltamethrin diverted glucose from the pentose cycle; this effect was larger with simultaneous injections. The relative participation of the glycolysis-Krebs cycle was slightly increased, and this effect was observed only when the injections were separated by 30 min. A direct dose-dependent response was observed only on the pentose cycle. An indirect action of deltamethrin on glucose catabolism pathways in fat body might be the most probable explanation, but we cannot eliminate the possibility of a direct effect on these catabolic pathways. Copyright (C) 1997 Elsevier Science Inc.