Excision or ablation* of the adenohypophysis (the anterior lobe of the hypophysis (pituitary gland).

The part that secretes growth hormone, fibroblast growth hormone, corticotropin, β-endorphin, thyrotropin, follicle-stimulating hormone, luteinizing hormone, and prolactin; these are released by hypophysiotropic hormones, releasing hormones secreted by the hypothalamus, and they regulate the functioning of the thyroid gland, gonads, adrenal cortex, and other endocrine organs.

As a consequence, the hypothalamo-pituitary unit is of vital importance to the growth, maturation, and reproduction of the individual.

*Ablation is usually carried out surgically; for example, the surgical removal of the thyroid gland (a total thyroidectomy) is an ablation of the thyroid.

The word ablation comes from the Latin ablatum, "to carry away".