Muscle LPL activity, plasma and muscle triglycerides in trained thyroidectomized rats.

A training-induced increase in muscle LPL activity was found only in euthyroid animals. However, muscle LPL activity is already elevated in non-exercised thyroid-deficient rats. Training caused similar or greater decreases in muscle and plasma TG levels in hypothyroid as compared to euthyroid animals. These data indicate that training-induced changes in TG metabolism are not dependent on an euthyroid status and suggest that a hypothyroid status may enhance TG utilization during exercise.