- How can the anterior part of the pituitary gland control the secretion of thyroid hormones?
- A. Some thyroid hormones are actually produced in the pituitary gland.
- B. If there are not enough thyroid hormones available in the body, the anterior pituitary can release thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid gland to release more thyroid hormone.
- C. It cannot affect the secretion of thyroid hormones.
- D. Growth hormone from the anterior pituitary gland can stimulate the secretion of thyroid hormones.
- E. None of the above.
Answer
- B. If there are not enough thyroid hormones available in the body, the anterior pituitary can release thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid gland to release more thyroid hormone.
Explanation
What happens is that the pituitary gland can still stimulate release of thyroid hormones in that the thyroid-releasing hormone (TRH) from the hypothalamus stimulates TSH from the pituitary helps in stimulating thyroid hormone release. Additionally, during this phase, in case the blood concentrations of thyroid hormones increase, they inhibit both TSH and TRH, leading to “shutdown” of thyroid epithelial cells and thus we can conclude that it is true to say if there are not enough thyroid hormones available in the body, the anterior pituitary can release thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid gland to release more thyroid hormone.