ATP content and adenylate energy charge of the mussel Mytilus edulis during the annual reproductive cycle in Lind�spollene, Western Norway

Abstract

Adenine nucleotide levels and the adenylate energy charge (EC) ratio of Mytilus edulis L. were determined at monthly intervals over a one-year cycle. The ATP concentration ranged from 2.7 to 4.7 mg · g-1 dry weight, being significantly (P<0.05) higher in spering and summer than in autumn and winter. The EC ratio ranged from 0.76 to 0.90 (annual mean 0.84), with the lowest values being found in the autumn. The change in the ATP concentration was related to the annual nutritional and reproductive cycle, as revealed by significant correlations with parameters such as gonad indexes, the contents of carbohydrate and ash, the calorific content, and the individual dry weight. The significant (P<0.001) seasonal variations in EC reflected mainly variations in the AMP content and showed no clear-cut relation to the overall annual reproductive cycle. It appears that the seasonal variations in the ATP concentration and the EC ratio to a large degree reflected changing weight-proportions of different tissues containing different amounts of adenine nucleotides.