Low Thyroid hormone levels in the blood

Patient X tends to be cold and have very low energy. You are an endocrinologist, and you first determine that X has low thyroid hormone levels in the blood. Your next step is to determine whether the problem lies at the level of the hypothalamus, anterior pituitary or the thyroid gland.Assume that you determine that the problem is very low secretion of TSH by the anterior pituitary, despite adequate levels of TRH. Describe two possible causes of this problem, and how you could gather evidence for those causes.

Assume that you can take small pieces of X’s anterior pituitary gland, keep it alive in a dish, and measure what you need to measure.

4. Possible cause #1 for low secretion of TSH by the anterior pituitary despite adequate TRH: (1 pt) 5. Experimental evidence that would support this cause: (1 pt) 6. Possible cause #2 for low secretion of TSH by the anterior pituitary despite adequate TRH: (1 pt) 7. Experimental evidence that would support this cause: (1 pt)

 

Please help with 4-7!!