Which of the following inhibits GH secretion from the anterior pituitary gland?
Growth hormone, also known as somatotropin, is secreted by somatotroph cells, which account for 50% of the anterior pituitary glands. The release of growth hormone from the anterior pituitary is pulsatile in nature, increasing after meals: with exercise, and during slow-wave sleep. Growth hormone, which is necessary for normal growth, exes its effects through mediators such as somatomedins and insulin-like growth factors. In addition to its involvement in growth, somatotropin is involved in stimulating the incorporation of amino acids into protein and inhibiting glucose uptake by tissues. By the latter effect, growth hormone helps restore low blood sugars to normal and is therefore a counterregulatory hormone to insulin. Both hypoglycemia and insulin stimulate growth hormone release, as does the presence of free amino acids such as arginine. Hypothalamic secretagogues also control growth hormone release. These molecules include the stimulatory hormone GHRH and the inhibitory hormone somatostatin (somatotropin release-inhibitory factor). The former is probably more impoant, since sectioning of the pathways between the hypothalamus and the anterior pituitary results in inhibition of growth hormone release. Other neurotransmitters influence growth hormone release, including hypothalamus-derived dopamine, which stimulates GHRH. -Adrenergic agonists stimulate growth hormone release, and -adrenergic blockers inhibit growth hormone increases. Serotonin agonists stimulate growth hormone release; this perhaps accounts for the nocturnal surge in growth hormone secretion. Ref - Harrison's principles of internal medicine 20e pg 2666t
Somatostatin
Growth hormone- releasing hormone (GHRH)
Hypoglycemia
Arginine
C.N.S