Data from: Mitochondrial function is enhanced by thyroid hormones during zebra finch development

An organism’s response to its environment is largely determined by changes
in the energy supplied by aerobic mitochondrial metabolism via
adenosine-tri-phosphate (ATP) production. ATP is especially important
under energy-demanding conditions, such as during rapid growth. It is
currently poorly understood how environmental factors influence energy
metabolism and mitochondrial functioning, but recent studies suggest a
role of thyroid hormones (TH). TH are key regulators of growth and
metabolism, and can be flexibly adjusted to environmental conditions, such
as environmental temperature or food availability. To test whether TH
enhancement is causally linked to mitochondrial function and growth, we
provided TH orally at physiological concentrations during the main growth
phase in zebra finch (Taeniopygia guttata) nestlings reared in a
challenging environment. TH-treatment accelerated maximal mitochondrial
working capacity – a trait that reflects mitochondrial ATP production,
without affecting growth. To our knowledge, this is the first study to
characterize the regulation of mitochondria by TH during development in a
semi-naturalistic context and to address implications for fitness related
traits, such as growth.