Timekeeping by the pineal gland.
N-Acetyltransferase, an enzyme involved in melatonin production in the pineal gland, exhibits a circadian rhythm in chickens with peak values in the dark-time and low values during the light-time, commencing at lights-on. When pineal glands of chickens killed during the dark-time (with high N-acetyltransferase activity) were organ-cultured, there was a decline in enzyme activity to light-time values. Regardless of the time of the dark at which the chickens were killed, the enzyme activity reached light-time levels at precisely the same time.
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001683:Biological Clocks; D002645:Chickens; D002940:Circadian Rhythm; D008027:Light; D009924:Organ Culture Techniques; D010870:Pineal Gland / Q000201:enzymology / Q000502:physiology*
D000123:Acetyltransferases