The pineal gland.
D000818:Animals; D001923:Brain Chemistry; D002940:Circadian Rhythm; D004971:Estrus; D005260:Female; D008322:Mammals; D008550:Melatonin / Q000096:biosynthesis*; D009638:Norepinephrine / Q000096:biosynthesis; D010870:Pineal Gland / Q000378:metabolism / Q000502:physiology; D011247:Pregnancy; D012701:Serotonin / Q000378:metabolism; D013045:Species Specificity; D009435:Synaptic Transmission
D012701:Serotonin; D008550:Melatonin; D009638:Norepinephrine