BIOLOGY 225 Unit 3

• Hypothalamus-pituitary-thyroid (HTP) axis: important for regulating metabolism, growth, and reproduction

  • TRH is secreted from the hypothalamus, stimulating TSH secretion from the anterior pituitary gland
  • TSH controls synthesis of T3 and T4 
  • T3 and T4 provide negative feedback and inhibit synthesis and release of both TRH and TSH