What is the function of the pituitary gland?
The pituitary gland, generally said "glands", is a twin-gland that is important in key functions of the body, e.g. metabolism.
The pituitary gland (s) is an endocrine gland (i.e. it secretes hormones within the bloodstream) about the size of a pea; it is a "twin", they are two. Further, it is a protrusion off the bottom of the hypothalamus at the base of the brain; see upcoming schemes.
Hormones secreted from the pituitary gland help control key functions, e.g. growth, blood pressure, certain functions of the sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, childbirth, nursing, water/salt concentration and the kidneys, temperature regulation and pain relief.
In some cases such as appetite control, there is a synergistic relation between the pituitary glands and the hypothalamus; by exchange of hormone product.