Metabolic adaptations by the leech Nephelopsis obscura during long‐term anoxia and recovery

Metabolic adaptations to long‐term (40 day) anoxia were determined in two size groups (small and large) of the freshwater leech Nephelopsis obscura . Neither size group accumulated the lactic acid during anoxia; rather succinate and alanine were the major end products. Glycogen and amino acids were the primary energy reserves utilized with lipid also utilized by small N. obscura . After 40 days of anoxia glycolytic flux was reduced by 99.8% in small and 99.7% in large N. obscura . Cellular energy status adenosine triphosphate/adenosine diphosphate (ATP/ADP) also declined significantly in small (79%) and large (69%) leeches. After return to normoxia the energy charge in small N. obscura was restored within 6 hours and glycogen, malate, succinate, alanine, and aspartate restored within 24 hours. Large N. obscura utilized lower proportions of their energy reserves than small N. obscura.