what gland, located in the brain, produces melatonin?
Pineal Gland. The pineal gland is a small, pinecone shaped gland of the endocrine system. A structure of the diencephalon of the brain, the pineal gland produces the hormone melatonin. Melatonin influences sexual development and sleep-wake cycles. The pineal gland is composed of cells called pinealocytes and cells of the nervous system called glial cells.