You are presented with the quiz "What is TSH regulated by?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "tRH stimulates the pituitary gland to produce thyroid-stimulating hormone, or TSH" and "tRH synthesis is regulated directly by thyroid hormones". 

So, what's the best answer to the question?


 

 pituitary          