Pituitary gland

The pituitary gland, also known as the hypophysis, is an endocrine gland found at the base of the brain just below the hypothalamus. It is connected to the hypothalamus by the pituitary stalk, which serves as a connection between the nervous and the endocrine system. The pituitary gland consists of two lobes, the anterior pituitary and the posterior pituitary both of which release hormones into the blood.

The anterior pituitary (adenohypophysis) consists of different endocrine tissue that synthesises and secretes six hormones which regulate homeostasis. The release of these hormones are regulated by the hypothalamic hypophysiotropic hormones, which are neurohormones produced in the parvocellular neurones of the hypothalamus. The neurohormones drain into the primary capillary plexus and are transported down to the anterior pituitary via the hypophyseal portal vessels.

The posterior pituitary (neurohypophysis) doesn't actually produce any hormones itself, only stores and secretes the hormones produced by the hypothalamus, a region of the brain that controls many homeostatic funtions^[1]. This is why the cell bodies of the neurones found in the posterior pituitary reside in the hypothalamus. The hormones are synthesised in the paraventricular nuclei and supraoptic nuclei of the magnocellular neurones.

Possible Pituitary Gland Disorders

Childhood and adolescent abnormal tumour growths on the pituitary gland can result in high levels of growth hormone. This can cause gigantism, characterised by abnormal limb growth and growth continuing on well after growth would be expected to stop due to the late fusion of growth plates^[2].

Growths on the pituitary gland in adulthood can cause acromegaly, the adult form of gigantism. This disorder also arises due to excessive growth hormone production but is instead characterised by excessive soft tissue growth and enlargement of the hands and feet. Further limb growth is not usually seen as the growth plates of the individual would usually be fused already. Type 2 diabetes and high blood pressure are commonly seen amongst the affected individuals^[3].

Reference

1. ↑ Silverthorn, D. (2013) Human Physiology: An Integrated Approach, 6th ed., Boston, Pearson Education, pp.219
2. ↑ Rostomyan, Liliya; Daly, Adrian F.; Petrossians, Patrick; Nachev, Emil; Lila, Anurag R.; Lecoq, Anne-Lise; Lecumberri, Beatriz; Trivellin, Giampaolo; Salvatori, Roberto (October 2015). "Clinical and genetic characterization of pituitary gigantism: an international collaborative study in 208 patients". Endocrine-Related Cancer. 22 (5): 745–757.
3. ↑ Ho, Ken (2011). Growth Hormone Related Diseases and Therapy: A Molecular and Physiological Perspective for the Clinician. Springer Science and Business Media. p. 400.