Endo 101: Control of the Endocrine System by Negative Feedback

One of the most important features of the endocrine system is its regulation (control) by negative feedback. This means that the glands within the endocrine system that stimulate the release of a hormone (for example, the pituitary) from another gland (for example, the thyroid) are eventually shut off, in a sense, so that too much hormone is not produced and a hormone imbalance is avoided.

As an example, the hypothalamus secretes TRH, which causes the pituitary to release TSH, which causes the thyroid gland to secrete T4 (thyroid hormone). When the body has enough thyroid hormone in the blood, T4 "feeds back" to the hypothalamus and pituitary and causes a decrease in secretion of TRH and TSH. This pattern of negative feedback is also true of the ovaries and testes, as well as the adrenal glands.