Correct option is A
The secretion of growth hormone (GH) is influenced by several physiological and environmental stimuli. Fasting increases GH secretion, as low glucose levels stimulate the hypothalamus to release growth hormone-releasing hormone (GHRH), leading to an increase in GH levels. This mechanism plays a role in maintaining glucose homeostasis during periods of caloric restriction.
On the other hand , REM sleep decreases GH secretion. GH is typically secreted in a pulsatile manner during the early stages of sleep, particularly during deep non-REM (NREM) sleep. However, during REM sleep, this secretion significantly declines.
Correct Options:
Statement A (Fasting increases GH secretion):During fasting or hypoglycemia, the body compensates for low glucose by stimulating GH secretion to promote gluconeogenesis and lipolysis. This GH release is mediated by increased GHRH and decreased somatostatin levels.
Statement B (REM sleep decreases GH secretion):Growth hormone release is highest during slow-wave sleep (deep NREM sleep). REM sleep, which occurs later in the sleep cycle, is associated with lower GH pulses.
Incorrect Options:
Statement C (Cortisol increases GH secretion):This is incorrect. Cortisol, a glucocorticoid, actually suppresses GH secretion when chronically elevated. High cortisol levels, as seen in conditions like Cushing’s syndrome, can blunt GH responses.
Statement D (Hypoglycemia decreases GH secretion):This is false. Hypoglycemia is a potent stimulator of GH secretion. The hypothalamus senses low blood sugar and prompts the pituitary to release GH to elevate glucose levels via gluconeogenesis.
