Chapter 1: Overview of the Endocrine System
4. Mechanisms of Hormone Regulation and Feedback Loops
4.1. Negative feedback
- The more common method of hormone regulation is the negative feedback loop.
- Negative feedback is characterized by the inhibition of further secretion of a hormone in response to adequate levels of that hormone.
- This allows blood levels of the hormone to be regulated within a narrow range.
- An example of a negative feedback loop is the release of thyroid hormones from the thyroid glands, as directed by the hypothalamus and pituitary gland (see Fig below)
As thyroxine concentrations in the blood rise, the hypothalamus and pituitary gland reduce their signaling to the thyroid glands to prevent additional thyroxine secretion.
