[In vivo protein synthesis in rainbow trout (Salmo gairdneri R.) muscle. Effect of temperature acclimatization]

Protein synthesis was measured in the muscle of trout acclimatized to 10 and 18 degrees C and weighing about 100 g. Fractional synthesis rate was calculated after a pulse injection of L-leucine U14C by fitting the specific radioactivity of the protein to the computed values obtained with the specific radioactivity of the precursor, according to a precursor product relationship (Martin et al., 1977). At 10 and 18 degrees C, fractional synthesis rate values were 0.9 and 1.2 p. 100/d (plasma as the precursor pool) and 1.9 and 1.8 p. 100/d (intracellular pool as the precursor), respectively. Muscle protein synthesis rates in young trout are lower than in young mammals (rat, rabbit, lamb), and temperature acclimatization had no influence on muscle protein synthesis in trout.