生长激素缺乏症（Growth hormone deficiency）.docVIP

生长激素缺乏症（Growth hormone deficiency） Second section growth hormone deficiency disease Growth hormone deficiency (growthhormonedeficiency, GHD) is due to the anterior pituitary growth hormone synthesis and secretion (growthhormone, GH) partially or completely lack, or due to abnormal structure, receptor defects and growth disorders. Its stature is in the same age, the same sex, the normal health, the child growth curve 300th sub digit or below two standard deviations, conforms to the low stature (shortstature) standard. The incidence rate is about 20 / 100 thousand to 25 / 100 thousand. [growth hormone synthesis, secretion, and function] Human growth hormone (hGH) is a single chain polypeptide composed of 191 amino acids synthesized and secreted by the anterior pituitary cells. Its molecular weight is 22KD and its coding gene GHl is 17q22 - 24. In the blood circulation, approximately 50% of GH is bound to the growth hormone binding protein (GHBP) and exists in the form of GH - GHBP complex. The release of growth hormone from two neurohormones in the hypothalamus, the growth hormone releasing hormone (GHRH) and growth hormone release inhibiting hormone (somatostatin, SRIH or GHIH) regulation. GHRH is a polypeptide containing 44 amino acid residues, which promotes the synthesis and secretion of GH by pituitary GH secreting cells. SRIH is a 14 peptide with a cyclic structure, which inhibits the secretion of GH by a variety of pro - stimulating agents. The interaction of pituitary in these two kinds of polypeptide under pulse release hGH, and the central nervous system by dopamine, 5 - serotonin and norepinephrine neurotransmitter regulates the secretion of hypothalamic GHRH and SRIH. HGH can act directly on cells and play a biological effect, but most of its functions must be mediated by insulin-like growth factors (insutin, likegrowthfactor, IGF). There are two kinds of IGF in human body, that is, IGF - I and IGF - ii. IGF - I is a single chain polypeptide molecular weig