<prompt> Melatonin is secreted by-HypothalamusAdrenal cortexPineal glandMelanocytes  <response>: Ans. is c? i.e.. Pineal gland o The pineal gland is a small cone shaped structure lies in the center of the brain behind the third ventricle. It consists of two types of cells : i Pinealocytes, and ii Neuroglial cell. Pinealocytes predominate and produce hormone melatonin N-acetyl-5-methoxytry famine. 