Changes in Glycogen, Pyruvate and Lactate in Rainbow Trout Salmo gairdneri) During and Following Muscular Activity

Abstract

Experiments upon muscular fatigue in [Formula: see text]-year-old rainbow trout (Salmo gairdneri) were carried out at the trout hatchery at Summerland, British Columbia during the summers of 1958 and 1959. Observations were made on hemoglobin, water content of muscle and whole blood, muscle and liver glycogen, and pyruvate and lactate in muscle, blood and liver. Experimental conditions included 30 min moderate activity, 2–15 min severe exercise, and recovery up to 24 hr following 15 min severe exercise. The results for hemoglobin, muscle and liver glycogen and blood lactate were similar to those reported earlier. Muscle glycogen was depleted 50% or more in the first 2 min of severe activity. Correlated with this rapid depletion of glycogen was a sudden accumulation of muscle pyruvate and lactate. Pyruvate and lactate likewise increased in the blood. While the disappearance of both pyruvate and lactate from muscle began immediately upon cessation of activity, resting levels were not approached until the 8th hr of recovery. During recovery, the levels of pyruvate and lactate in the blood after severe exercise continued to increase for the first hour, remained elevated for at least 8 hr and did not return to the resting level until the 12th–24th hr. Muscle glycogen was not restored above half the resting level at the end of 24 hr. Interpretations of the data in relation to metabolism in rainbow trout are discussed.