<P> The anterior pituitary is derived from the ectoderm, more specifically from that of Rathke's pouch, part of the developing hard palate in the embryo . </P> <P> The pouch eventually loses its connection with the pharynx, giving rise to the anterior pituitary . The anterior wall of Rathke's pouch proliferates, filling most of the pouch to form the pars distalis and the pars tuberalis . The posterior wall of the anterior pituitary forms the pars intermedia . Its formation from the soft tissues of the upper palate contrasts with the posterior pituitary, which originates from neuroectoderm . </P> <P> The 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 . </P> <P> 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 cascading physiological responses . </P>

Anterior pituitary cell that produces lh and fsh