Hormone release is controlled by negative feedback loops that may include a releasing hormone that causes the release of a stimulating hormone that causes the release of the hormone itself, in addition to its target cell or tissue and its response . Neurohormones are secreted by neurons into the blood. The pituitary gland is the link between the nervous system and many endocrine glands because it is under the influence of brain hormones and its hormones control the activities of various endocrine glands in the body. The posterior pituitary releases hormones that are synthesized into vesicles that walk down microtubules in neurons from the hypothalamus to the pituitary where the hormones are released after appropriate signals. Oxytocin stimulates contraction of the uterus and is involved in the positive feedback loop at birth.
Antidiuretic hormone affects the kidneys to save water .
Aldosterone will be studied later in the chapter on salt and water balance. Prolactin is released under the balance between prolactin releasing hormone and prolactin inhibiting hormone produced in the hypothalamus. Prolactin acts on the breasts in female mammals to stimulate milk production . Prolactin assists with endocrine function of the testes in male mammals. Growth hormone is released under the balance between growth hormone releasing hormone and growth hormone inhibiting hormone produced in the hypothalamus.