Pineal GlandNorepinephrineMelatoninAcetylserotonin O-MethyltransferasePinealomaArylalkylamine N-AcetyltransferaseCircadian RhythmNorepinephrine Plasma Membrane Transport ProteinsReceptors, MelatoninSalivary GlandsMammary Glands, AnimalArylamine N-AcetyltransferaseExocrine GlandsSubmandibular GlandPhotoperiodLightDarknessParotid GlandSerotoninSweat GlandsEpinephrineReceptors, AdrenergicRats, Inbred StrainsSympathetic Nervous SystemRetinaReceptor, Melatonin, MT1Rats, Sprague-DawleyChickensSebaceous GlandsCatecholaminesAdrenal GlandsSublingual Gland