Resorption und Stoffwechsel von Glucose im Darmtrakt der Wanderheuschrecke Locusta migratoria

• Published in: Journal of insect physiology Vol. 20; no. 12; pp. 2385 - 2396
• Main Authors: Droste, H.-J., Zebe, E.
• Format: Journal Article
• Language: German
• Published: Elsevier Ltd 1974
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/0022-1910(74)90025-0

Absorption and metabolic fate of 14C-glucose after injection into mid-gut preparations from Locusta migratoria were studied in vitro. After 5 min nearly half of the total radioactivity had already passed into the incubation medium and in 2 hr there was an increase to 75 per cent. The radioactivity in the medium was found mainly in glucose and fructose, which were approximately equally labelled, and a minor part appeared in the organic acid and sugar phosphate fraction. This pattern of labelling changed drastically when non-radio active glucose was present in the incubation mixture. In these experiments an extensive synthesis of sucrose could be demonstrated. Sucrose formation from UDP- 14C-glucose by mid-gut homogenates was stimulated by fructose-6-phosphate. The appearance of radioactivity in the contents of the gut and in the faeces was demonstrated in in vivo experiments after injection of 14C-glucose into the haemolymph. Sugar concentrations in the haemolymph of locusts were measured after 24 hr starvation and after feeding. The levels of glucose, fructose, and sucrose were very low in the starving animals and increased ten- to twenty-fold after feeding. The trehalose concentrations remained high and relatively constant. The activities of 18 enzymes of the intermediary metabolism were assayed in the fore-, mid-, and hindgut.