Harderian gland: influence on pineal hydroxyindole-O-methyltransferase activity in neonatal rats.
A circadian rhythm has been found in hydroxyindole-O-methyltransferase activity of the pineal gland of blinded 12-day-old rats. Five additional hours of lighting can partly prevent the nocturnal increase in pineal hydroxyindole-O-methyltransferase activity in such rats. Removal of the Harderian gland abolishes this response to light in 12-day-old blinded animals, giving further support to the suggestion that this gland may function as an extraretinal photosensitive organ influencing the pineal gland in blinded suckling rats.
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002247:Carbon Isotopes; D003624:Darkness; D007765:Lacrimal Apparatus / Q000502:physiology*; D008027:Light; D008550:Melatonin / Q000096:biosynthesis; D010870:Pineal Gland / Q000201:enzymology*; D011830:Radiation Effects; D051381:Rats; D014166:Transferases / Q000378:metabolism*
D002247:Carbon Isotopes; D014166:Transferases; D008550:Melatonin