The synthesis of TSH is
A) negatively regulated by TRH
B) positively regulated by thyroxine levels
C) regulated both by TRH and thyroxine levels in blood
D) at the top of HPA axis and therefore is not regulated by other hormones

Question

Quizplus · Accepted Answer

The synthesis of TSH is regulated by both TRH and thyroxine levels in the blood. TRH stimulates the synthesis and release of TSH, while thyroxine levels in the blood provide negative feedback to the hypothalamus and pituitary gland, inhibiting the further release of TRH and TSH.

The Synthesis of TSH Is