Meeting Abstract
Thyroid hormones play a key role in regulating metabolic rates in mammals and some non-mammal species. Thyroid hormones, especially triiodothyronine (T3), also play a role in altering mitochondrial number and function, as well as oxidative phosphorylation pathways, in skeletal muscle after exercise or increased activity. However, research concerning the role T3 plays in whole-body and muscle metabolism via mitochondrial biogenesis in nonmammals has mixed results. In our study, we experimentally manipulated 40 male green anole lizards split into two treatment groups, with the first group assigned saline injections, and the second group assigned T3 injections. We expected T3 to elevate both whole-body metabolic rate as well as oxygen consumption rate of skeletal muscle fibers. However, we discovered that T3 did not elevate whole-body metabolic rate or oxygen consumption rate of skeletal muscle tissue compared to controls. Our results suggest that either thyroxine (T4) may be the biologically active form for eliciting specific physiological responses in ectotherms instead of T3, or thyroid hormones have fundamentally different roles in lizards compared to mammals.
