Hypothalamic–pituitary–gonadal axis controls development, reproduction, and aging in animals. Gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus by GnRH-expressing neurons. The anterior portion of the pituitary gland produces luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonads produce estrogen and testosterone. In oviparous organisms (e.g. fish, reptiles, amphibians, birds), the HPG axis is commonly referred to as the hypothalamus-pituitary-gonadal-liver axis (HPGL-axis) in females. Many egg-yolk and chorionic proteins are synthesized heterologously in the liver, which are necessary for oocyte growth and development. Examples of such necessary liver proteins are vitellogenin and choriogenin. The HPA, HPG, and HPT axes are three pathways
Pituitary stalk interruption syndrome Pituitary stalk interruption syndrome Pituitary stalk interruption syndrome (PSIS) is a congenital disorder characterised by the triad of an absent or exceedingly thin pituitary stalk, an ectopic or absent posterior pituitary and/or absent or hypoplastic anterior pituitary. Affected individuals may present with hypoglycaemia during the neonatal period, or with growth retardation during childhood (those diagnosed in the neonatal period appear to be affected by a particularly severe form of the disorder). PSIS is a common cause of congenital hypopituitarism, and causes a permanent growth hormone deficit. Some PSIS-affected individuals may also present with adrenal hypoplasia (5-29%), diabetes insipidus (5-29%), primary