Changes in Enzyme Activities Related to Glycerol Synthesis in Hibernating Larvae of the Rice Stem Borer, Chilo Suppressalis WALKER

Abstract

To elucidate the interconversion between glycogen and glycerol transformation in hibernating larvae of the rice stem borer, Chilo suppressalis WALKER, glucose-6-phosphate dehydrogenase, α-glycerophosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase activities were examined. The properties of these enzymes resemble those determined on other insects and the enzymes seem to function on the glycolytic and pentose phosphate pathways. High activity of glucose-6-phosphate dehydrogenase at the initiation of diapause implies that the pentose phosphate cycle is active during diapausing stages. A continuous rise in α-glycerophosphate dehydrogenase activity and decreases in activities of lactate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase are observed during pre-diapausing stages. Especially, α-glycerophosphate dehydrogenase exhibited predominant activity in fat body during these periods. From these results the mechanism of glycerol production is discussed in relation to diapause physiology of this insect.