Hypothalamic–pituitary–somatotropic axis Hypothalamic–pituitary–somatotropic axis The hypothalamic–pituitary–somatotropic axis (HPS axis), or hypothalamic–pituitary–somatic axis, also known as the hypothalamic–pituitary–growth axis, is a hypothalamic–pituitary axis which includes the secretion of growth hormone (GH; somatotropin) from the somatotropes of the pituitary gland into the circulation and the subsequent stimulation of insulin-like growth factor 1 (IGF-1; somatomedin-1) production by GH in tissues such as, namely, the liver. Other hypothalamic–pituitary hormones such as growth hormone-releasing hormone (GHRH; somatocrinin), growth hormone-inhibiting hormone (GHIH; somatostatin), and ghrelin () are involved in the control of GH secretion from the pituitary gland. The HPS axis is involved in postnatal human growth. Individuals
Pituitary apoplexy replacement; in this case, blood levels of cortisol are determined at 9:00 AM (as cortisol levels vary over the day). A level below 550 nmol/l indicates a need for replacement. The decision on whether to surgically decompress the pituitary gland is complex and mainly dependent on the severity of visual loss and visual field defects. If visual acuity is severely reduced, there are large or worsening visual field defects, or the level of consciousness falls consistently, professional guidelines recommend that surgery is performed. Most commonly, operations on the pituitary gland are performed through transsphenoidal surgery. In this procedure, surgical instruments