The influence of food intake and ambient temperature on the rate of thyroxine utilization.

Young growing pigs of both sexes were subjected to changes in (1) energy intake, (2) ambient temperature, and (3) bulk of food. The rate of disappearance of injected 125I-labelled thyroxine from the plasma (K) was measured. An analysis of variance revealed that the effect attributable to changes in the energy content of the food intake was statistically significant (P less 0-01). A change in ambient temperature had no statistically significant effect on K, nor did a change in the bulk of food when energy intake was constant (P less than 0-05).