Premium
T3: Does It Really Make the Alligator Go “Tick, Tock”?
Author(s) -
Sirsat Tushar Saoji,
Sirsat Sarah K Goy,
Dzialowski Edward M
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.714.17
Subject(s) - alligator , respiration , endocrinology , ectotherm , medicine , biology , skeletal muscle , respirometry , thyroid , mitochondrion , thermoregulation , hormone , physiology , anatomy , zoology , biochemistry , ecology
Thyroid hormones (TH) are key regulators of vertebrate metabolism and are thought to regulate the development of endothermy in mammals and birds. In order to better understand the effect of TH on development of metabolic physiology of an ectothermic species, we treated neonate American alligators with triiodothryronine (T 3 ) or the thyroperoxidase inhibitor, methimazole, for 28 days to induce hyperthyroidism and hypothyroidism, respectively. We measured whole animal O 2 consumption (VO 2 ) by flow though respirometry followed by isolated mitochondria respiration from cardiac muscle and hind limb thigh skeletal muscle. Whole animal VO 2 of T 3 and methimazole treated subjects differed significantly from control: hyperthyroid animals exhibited higher VO 2 while hypothyroid animals showed lower VO 2 , independent of body mass. These differences were present after five days of exposure and were maintained through day 28. The LEAK and OXPHOS states of respiration of isolated cardiac and skeletal mitochondria from hypothyroid animals were significantly lower than control mitochondria. There were no differences in mitochondrial respiration between hyperthyroid and control animals. We provide support that T 3 acts as a metabolic regulator of the American alligator at both the whole animal and mitochondrial level and plays a role in early development of neonate metabolism. Supported by NSF IOS 1146758 (EMD).