PHYSIOLOGY AND CLINICAL SIGNIFICANCE OF THE SOMATOTROPIC HORMONE

Аннотация

The somatotropic hormone (STH), or growth hormone, is one of the key peptide hormones that regulates growth and metabolic processes in the human body. This article provides an in-depth analysis of the biosynthesis, secretion mechanisms, physiological effects, clinical significance, and pathological conditions associated with STH. Disorders such as gigantism, acromegaly, and pituitary dwarfism, as well as diagnostic and treatment methods, are reviewed on a scientific basis. The article also highlights the role and prospects ofSTHin modern clinical medicine. Keywords: Somatotropin, growth hormone, gigantism, acromegaly, dwarfism, insulin-like growth factor (IGF-1) Introduction. The somatotropic hormone (STH), or growth hormone, is a polypeptide hormone consisting of 191amino acids, produced bythe anterior pituitary gland. It regulates growth, cell proliferation, and regeneration processes in the body. The effects of STH are exerted both directly and indirectly through insulin-like growth factor 1 (IGF-1). In recent years, it has been demonstrated that STH not only influences growth but also has significant effects on metabolic, immune, and cognitive systems. The aim of this article is to analyze thephysiology, clinical significance, and treatment approaches ofthe somatotropichormone. Definition andimportance. Somatotropic hormone (GH) is apeptide hormone produced by the anterior pituitary (adenohypophysis), essential for growth, cell regeneration, and metabolism in humans and other vertebrates. Adequate production ensures normal physical development in children and adolescents, and in adults, it helps maintain muscle and bone tissue. 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www Structure and synthesis of growth hormone. GH is a single-chain peptide composed of 191 amino acids, with a molecular weight of approximately 22 kDa. It is synthesized by somatotroph cells in the pituitary gland and regulated by the hypothalamus. Growth hormone-releasing hormone (GHRH) from the hypothalamus stimulates GH secretion, whereas somatostatin inhibits it. Synthesis stages: Somatotrophs synthesize the hormone as preprosomatotropin. Preprosomatotropin is transferred to the endoplasmic reticulum, where it is processed into the propeptide form. Prosomatotropin is cleaved by proteolytic enzymes into active GH and secreted into thebloodstream. 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www Physiological functions of growth hormone. GH exerts both direct and indirect effects (via IGF-1). Its functions include: Growth stimulation Stimulates the production of IGF-1 in the liver and other tissues. Enhances the retention of water and minerals in bone and cartilage tissues. Increases proliferation and differentiation of chondrocytes. Effects on metabolism. Carbohydrate metabolism: Antagonizes insulin action, increases glycogenolysis and gluconeogenesis. Lipid metabolism: Stimulates lipolysis, increasing the release of free fatty acids from adipose tissue. Protein metabolism: Promotes protein synthesis, shifts nitrogen balance towards positive. Mineral metabolism . Enhances calcium and phosphate absorption, strengthening bone tissue. Regulation of Growth Hormone Secretion Stimulants: Sleep (especially deep sleep), physical activity, stress, fasting, low blood glucose levels. Inhibitors: High glucose and fatty acid levels, IGF-1 (negative feedback), somatostatin. GHsecretion follows acircadian rhythm, peaking between 23:00 and 2:00AM. Hypersecretion Gigantism: Excess GH secretion in children and adolescents leads to excessive growth of body parts. Acromegaly: Excess GH secretion in adults causes abnormal enlargement of hands, feet, facial bones, and soft tissues. Causes: Pituitary adenoma, hypothalamic disorders. Clinical features: Coarse facial features (hyperostosis), enlargement of hands and feet, thickening of the neck, diabetes, arterial hypertension. Hyposecretion. Pituitary dwarfism (growth hormone deficiency): GH deficiency in children leads to slow growth and short stature. Causes: Congenital pituitary anomalies, brain trauma, infections. Clinical features: Short neck, normal body proportions, delayed sexual maturation. 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www Diagnosis and Treatment Diagnosis. Blood tests: GH and IGF-1 levels. Stimulation and suppression tests: Insulin- induced hypoglycemia test, oral glucose suppression test. Radiological studies: Pituitary MRI/CT, bone X-ray (hands and wrists). Treatment . Hyposecretion: Replacement therapy with recombinant growth hormone (somatotropin). Hypersecretion: Surgery (removal of pituitary adenoma). Radiotherapy Pharmacotherapy (somatostatin analogues —octreotide, lanreotide; dopamine agonists)