False about secretion of melatonin
High-Yield Explanation
(C) Increase secretion during daylight hours # PINEAL GLAND:> The pineal gland (epiphysis), believed by Desecrates to be the seat of the soul, has at one time or another been regarded as having a wide variety of functions.> It is now known to secrete melatonin, and it may function as a timing device to keep internal events synchronized with the light-dark cycle in the environment> Regulation of Secretion: In humans and all other species studied to date, melatonin synthesis and secretion are increased during the dark period of the day and maintained at a low level during the daylight hours. This remarkable diurnal variation in secretion is brought about by norepinephrine secreted by the postganglionic sympathetic nerves that innervate the pineal. The norepinephrine acts via p-adrenergic receptors in the pineal to increase intracellular cAMP, and the cAMP in turn produces a marked increase in N-acetyltransferase activity. This results in increased melatonin synthesis and secretion.