| Abstract | The ability of the fat body to synthesize lipid during development of the adult male desert locust has been investigated by following the rates of incorporation of labelled glucose, trehalose, acetate, and citrate into fat body lipid. There is a small increase in lipogenesis during the first 3 days of adult life, but the major period of lipogenesis occurs between day 5 and day 7. The mature insect then maintains a relatively high capacity for lipogenesis. The patterns of glucose and trehalose incorporation into lipid are similar to that of acetate, thus the insect has the capacity to convert carbohydrate to lipid during development. Citrate incorporation parallels the acetate incorporation and is thought to be an important intermediate in the conversion of carbohydrate to lipid in the locust. The amounts of these metabolites oxidized for energy production in relation to the amounts converted to lipid during development was also investigated. The capacity of the fat body for lipid oxidation during development was investigated by following the rate of breakdown of labelled palmitate to acid soluble material and CO2. The ability to oxidize lipid is low during the first 6 days of adult life, then increases rapidly between day 6 and day 8, and remains at a high level until 14 days. From these results it is clear that the fat body synthesizes lipid during the first 7 days of adult life and subsequently oxidizes this accumulated lipid. These overall changes in metabolism can be correlated with the changes in the lipid content of the fat body and changes in the activities of enzymes associated with lipogenesis measured in previous work. The ability of flight muscle to oxidize both lipid and carbohydrate for energy production was also investigated by measuring the rate of oxidation of labelled trehalose and palmitate by this tissue. It was found that flight muscle has the capacity to oxidize both lipid and carbohydrate at all stages of development. |
|---|
