Contributions à la biochimie du ver à soie. XXX. Biosynthèse de tréhalose et de glycogène à partir de glucose-1-phosphate

1. When injected into silkworms in the middle of the fifth larval instar, labelled G-1-P is principally used for the synthesis of hemolymph trehalose. 2. Glycogen synthesis from the same source in the fat body proceeds more rapidly in undernourished larvae than in those fed normally. 3. Owing to the poor incorporation of the radioactivity in the glycogen and especially in the trehalose of the fat body, it is suggested that the trehalose could be synthesized from pyruvate elsewhere than in the fat body, and that the biosynthetic pathway of trehalose from pyruvate does not necessarily pass through glycogen. 4. The synthesis of trehalose and glycogen, as well as the hydrolysis of glycogen, could be controlled, directly or indirectly, by the variations of the trehalose level in the hemolymph. 5. The gluconeogenetic pathways in the silkworm are discussed and presented in the form of a partially hypothetical figure.