Pituitary gland growth hormone-secreting

Human growth hormone (hGH) is a polypeptide with 191 amino acids. It is secreted by the pituitary gland. This hormone stimulates the production of insulin-like growth factor-1 (IGF-1) from the liver. Most of the positive effects of hGH are mediated by the IGF-1 system, which also includes specific binding proteins. 

With increasing age the pituitary gland decreases in size, and the incidence of microadenomas and focal necrosis increases. Gonadotrophin and AVP secretion increase, and growth hormone secretion decreases. The significance of the latter is the subject of much current investigation. 

Growth hormone (GH) is an endocrine hormone produced and stored in the anterior pituitary gland, which is secreted into the blood circulation in a pulsation... 

Combined immunohistochemical, in situ hybridisation, and biochemical studies provide evidence for nitric oxide synthase synthesis in two cell populations of the anterior pituitary gland, gonadotrophs and folliculo-stellate cells, and for an inhibitory effect of NO on stimulated release of LH (Cec-CATELLi et al. 1993). The folhculo-stellate cells do not produce any known hormones (Horvath and Kovacs 1988) but may indirectly influence growth-hormone secretion. Thioredoxin was prominently localised in the folliculo-stellate cells of the mammalian adenohypophysis while only a minor proportion of the glandular cells were positive (Padilla et al. 1992). Glutaredoxin localisation in the adenohypophysis resembled that of thioredoxin. 

A polypeptide hormone secreted by the anterior pituitary gland in both males and females. The highest serum levels occur in pregnancy, when, along with other hormones, it promotes lactation and mammary gland growth. Prolactin secretion, unlike other pituitary hormones, is limited by a hypothalamic prolactin-release inhibiting factor (PIF). 

GH synthesis and secretion does not disappear when linear growth is complete. In fact isolation of hGH from cadaver pituitary glands would not have been possible if it did. Physicians caring for adult patients with pituitary disease began to realize that even with optimum replacement of other hormones, patients who acquired GH deficiency in adulthood complained bitterly about diminished quality of life. Studies from Europe also documented increased cardiovascular morbidity and mortality in these patients [13], Because it was no longer necessary to conserve scarce supplies of hGH for use in children, physicians were able to study GH effects in adults with growth hormone deficiency. These studies have shown that GH improves body composition (decreases fat mass and increases lean body mass) and decreases risk factors for cardiovascular disease [14]. 

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