Ghrelina e secretagogos do hormônio de crescimento (GHS): modulação da secreção do hormônio de crescimento e perspectivas terapêuticas

Abstract

RESUMOA secreção do hormônio de crescimento (gH) é modulada pelo hormônio liberador de hormônio de crescimento (gHrH) e pela somatostatina. na últi-ma década foi descoberto um terceiro mecanismo de controle, envolvendo os secretagogos de gH (gHs). A ghrelina, o ligante endógeno do receptor dos gHs, é um peptídeo acilado produzido no estômago, que também é sintetizado no hipotálamo. este peptídeo é capaz de liberar gH, além de aumentar a ingesta alimentar. A ghrelina endógena parece amplificar o padrão básico de secreção de gH, ampliando a resposta do somatotrofo ao gHrH, estimulando múltiplas vias intracelulares interdependentes. entretanto, seu local de atuação predominante é o hipotálamo. neste trabalho, será apresentada revisão sobre a descoberta da ghrelina, os mecanismos de ação e o possível papel fisiológico dos gHs e da ghrelina na secreção de gH e, finalmente, as possíveis aplicações terapêuticas destes compostos. ABSTRAcT Ghrelin and Growth Hormone Secretagogues (GHS): Modulation of GrowthHormone Secretion and Therapeutic Applications. growth hormone-releasing hormone (gHrH) and somatostatin modulate growth hormone (gH) secretion. A third mechanism was discovered in the last decade, involving the action of growth hormone secretagogues (gHs). ghrelin, the endogenous ligand of the gHs-receptor, is an acylated peptide mainly produced by the stomach, but also synthesized in the hypothalamus. this compound increases both gH release and food intake. endogenous ghrelin might amplify the basic pattern of gH secretion, optimizing somatotroph responsiveness to gHrH, activating multiple interdependent intracellular pathways. However, its main site of action is the hypothalamus. in the current paper it is reviewed the available data on the discovery of this peptide, the mechanisms of action and possible physiological roles of the gHs and ghrelin on gH secretion, and finally, the possible therapeutic applications of these compounds.

Shift work and its association with metabolic disorders

“…It is also associated with gastrointestinal functioning and the kinetic properties of the stomach. Unlike most intestinal hormones, ghrelin serum levels increase during fasting and reduce after food intake [ 50 ].…”

Which factors are associated with sarcopenia and frailty in elderly persons residing in the community?

“…In addition to the hormones already mentioned, one of the selected studies emphasizes the relationship between the hormone ghrelin and sarcopenia, as the sarcopenic individuals presented significantly lower levels of ghrelin than those without sarcopenia 18 . Ghrelin is an appetite stimulant and inducer of growth hormone (GH), and the low levels of this hormone associated with the anorexia of aging trigger a cascade of events that predisposes the individual to developing sarcopenia 33 .…”