Normal function of the hypothalamus and pituitary gland are essential to the
function of many other glands and hormone systems. The hypothalamus and pituitary gland coordinate hormone secretion by the thyroid gland, the adrenal glands, and the gonads, and the pituitary gland directly secretes prolactin, growth hormone, vasopressin, and oxytocin. The hypothalamic-pituitary-peripheral target gland axes function by means of traditional feedback loops whereby small peptide hormones secreted by the hypothalamus act as trophic and in some cases as inhibitory factors that control the release of pituitary hormones, which in turn control target gland hormone secretion. Negative feedback of target hormone on pituitary and hypothalamic hormone secretion then occurs.