Posterior pituitary Posterior pituitary The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. The posterior pituitary is not glandular as is the anterior pituitary. Instead, it is largely a collection of axonal projections from the hypothalamus that terminate behind the anterior pituitary, and serve as a site for the secretion of neurohypophysial hormones (oxytocin and vasopressin) directly into the blood. The hypothalamic–neurohypophyseal system is composed of the hypothalamus (the paraventricular nucleus and supraoptic nucleus), posterior pituitary, and these axonal projections. The posterior pituitary consists mainly of neuronal projections (axons) of magnocellular
Anterior pituitary anterior pituitary contains five types of endocrine cell, and they are defined by the hormones they secrete: somatotropes (GH); Lactotropes (PRL); gonadotropes (LH and FSH); corticotropes (ACTH) and thyrotropes (TSH). It also contains non-endocrine folliculostellate cells which are thought to stimulate and support the endocrine cell populations. Hormones secreted by the anterior pituitary are trophic hormones (Greek: trophe, “nourishment”) and tropic hormones. "Trophic hormones" directly affect growth either as hyperplasia or hypertrophy on the tissue it is stimulating. "Tropic hormones" are named for their ability to act directly on target tissues or other endocrine glands to release hormones, causing numerous