Metabolism in the Crayfish Astacus Astacus (L.): II. – The Energy-Yielding Metabolism

Abstract

The energy-yielding metabolism in Aslaciw astacus was studied. The connection between the oxidative metabolism and the carbohydrate, lipid and protein metabolism lias been investigated. It appeared that both acetate and glucose can be oxidized. The acetate is oxidized more rapidly than glucose, because the latter is stored as glycogen first. The CO₂ from the respiration is fixed partly by the exoskeleton and pyruvic acid (but to a lower degree), and partly expired. The quantity of expired CO₂ is much larger in eyesfalkless animals than in intact animals, (hough the labelling of the CO₂ with carbon-14 is the same in both cases. Much more carbon-H from acetate is incorporated in the fatly acids than from glucose. Glucose is stored as glycogen and is gradually taken into circulation again from this source. In intact animals storage of glycogen takes place both in the hepatopancreas and in the muscles. In eyestalkless animals glycogen is stored mainly in the hepatopancreas. Probably glycogen is the principal form of energy storage and the glucose from this source the most important substrate for the production of energy by the Embden-Meyerhof way and TC.A-cycle. In view of the small quantities in which lipids are always found, and the low labelling of the fatty acids in comparison with the amino acids, it may be concluded that lipids are less important than amino acids are for energy storage in Aslacus aslacus. In animals of the intennolt stage, chit-in is labelled after injection of ¹⁴C-glucose. In eyestalkless animals there is an important decrease of the fatty acids from the hepatopancreas. For the nonsaponifiable lipids hardly any decrease could lie found.