what is pineal gland used for?
<answer> The melatonin secreted by the pineal gland is responsible for various aspects of sexual development, animal hibernation, metabolism, and seasonal breeding. <context> The pineal gland is an endocrine gland, like the pituitary gland, thyroid gland, adrenal gland, and pancreas. Like other endocrine glands, it secretes a hormone -- in this case melatonin.d. In reality, the melatonin secreted by the pineal gland is responsible for various aspects of sexual development, animal hibernation, metabolism, and seasonal breeding. The gland secretes its hormone in sync with circadian rhythms, releasing more in the dark and less in the light.