University:
York University
Course:
SC/BIOL 4320 | Vertebrate Endocrinology
Academic year:

2023
Views:

491

Pages:

2
Author:

Niklas

Thyroid hormone functions Oxidative Phosphorylation Metabolic actions a. Stimulate BMR Basal Metabolic Rate energy expenditure at rest b. Stimulate thermogenesis through uncoupling of oxidative phosphorylation (UCP-1 makes reaction less efficient, turns glucose + heat → ATP) ↑ T3 ↑ synthesis of UCP-1 Brown Adipose Tissue (where UCP-1) c. Stimulate synthesis of metabolic proteins Succinoxidase Cytochrome C Cytochrome oxidase → All involved in Krebs cycle or electron transport chain 2. Growth differentiation a. Synergistic w/ GH on body (by adding together, they promote each other) combined effect >> added effect GH needs TH for maximum effect b. Nervous system development * most important, occurs w/ I deficiency missing TH during development permanent brain damage helps to put basic structures together c. Nervous system function Missing TH after development transient disruption of brain function can be fixed Hypothyroid people exhibit slow mental activity 3. Hair replacement low TH → high hair loss (↑ cortisol) high TH → low hair growth (↓ cortisol) 4. Reproduction Hypothyroid individuals show delayed sexual maturation decreased androgen (males) irregular ovarian cycles (females) 5. Permissive roles - The allow other bioregulators to do their job allow other bioregulators to function ↑ adenyl cyclase levels affects responsiveness from CNS hypothyroidism depresses all body functions Recap: -Know three classes of deiodinases and their locations. -Know two major thyroid bioassays and what they actually tell us. -Know the major thyroid hormone functions in metabolism, growth/differentiation, hair replacement, reproduction, and permissive function. CLICKER QUESTION #40 (0.5 performance pt.) A person missing Type II deiodinase will likely have: a. elevated TSH. b. elevated T4. c. a goiter d. All of the above. e. a and c only.