Question

Mary presents with symptoms of hyperthyroidism.

1. What would some of those symptoms be?

2. Her blood panel shows elevated T3, elevated TSH, and depressed TRH. Which gland is not working correctly?

3. Based on this, are there any other hormones that might also be elevated?

4. For TSH, TRH, and T3, does each bind an internal or external receptor?

Answer 1

1) Thyroid hormone increases the basal metabolic rate of body. So the most common symptoms of hyperthyroidism include weight loss, irregular heartbeat and increased sweating.

2) Problem lies in pituitary which cause increased secretion of TSH and therefore increased secretion of T3 from thyroid gland. Increased T3 cause negative feedback to hypothalamus to cause decreased secretion of TRH. But there is increased TSH without the need of TRH so there might be some defect in pituitary.

3)As there is hyperactivity of anterior pituitary , other hormones of anterior pituitary can also be present in increased concentration such as ACTH, LH, FSH, GH and prolactin.

4)TSH and TRH has the cell membrane receptors- G protein coupled receptors.(external receptors)

T3 acts on the nuclear receptors. (Internal receptors)