The pituitary gland is about the size of a pea in humans. It produces releasing hormones that direct the glands of the body to secrete more or less hormone making it the master of the hormone system.
For example, TSH (Thyroid Stimulating Hormone) is a pituitary hormone that is secreted when the body needs more hormone production from the thyroid. An elevated TSH can be interpreted as an indication of a low functioning thyroid since the pituitary is increasing its signal to the thyroid because the thyroid is not responding.
Holistic & Integrative Medicine