Melatonin is a molecule that is produced in the pineal gland and secreted into the blood. melatonin then travels to different parts of the brain. it causes drowsiness and decreases body temperature to assist in the regulation of the sleep/wake cycle. what kind of control is used to regulate this molecule? a. muscular control, because the muscles can be used to control the release of melatonin b. neural control, because the brain sends the signal to release melatonin through nerve cells c. cardiovascular control, because melatonin flows through the blood to deliver the message d. endocrine control, because melatonin is secreted into the blood and regulates body processes