pineal body [L, pineas, pine cone; AS, bodig, body] , a cone-shaped structure in the brain, situated between the superior colliculi, the pulvinar, and the splenicum of the corpus callosum. Its precise function has not been established. It may secrete the hormone melatonin, which appears to inhibit the secretion of luteinizing hormone. Also called epiphysis cerebri, pineal gland.
