Effects of thyroidal status on metabolism and growth of juvenile turtles, Pseudemys scripta elegans

1. 1. Long-term goitrogen or thyroxine (T 4) treatment were used to study the role of the thyroid in growth and metabolism of juvenile turtles. 2. 2. In one study where methimazole had varying effects on thyroid function, growth was correlated with plasma T 4. 3. 3. In a second study, turtles treated with methimazole had depressed appetites and growth rates after 4. 8 weeks of treatment; concurrent treatment with T 4 prevented this depression. 5. 4. Hypothyroid turtles did not have significantly lower oxygen consumption ( dot V Oin2 ) than controls; T 4-injected turtles had higher V dot Oin2 compared to saline-injected controls, but not uninjected controls. 6. 5. Fasting for 10 days significantly depressed V dot Oin2 but did not alter other thyroid parameters measured.