Boonsirm WithyachumnarnkulKanokbhan BuppanirojAnchalee Pongsa-AsawapaiboonMahidol University2018-08-102018-08-101992-01-01Comparative Biochemistry and Physiology -- Part A: Physiology. Vol.102, No.4 (1992), 703-707030096292-s2.0-0026777390https://repository.li.mahidol.ac.th/handle/20.500.14594/222611. 1. N-Acetyltransferase (NAT), and melatonin were determined at 3-hour intervals in the optic lobe of the giant freshwater prawn, Macrobrachium rosenbergii de Man. 2. 2. A relatively high activity of NAT, compared to that in rat pineal, was found in the tissue. The enzyme did not show a significant diurnal rhythm although a slight suppressive level was detected at night. 3. 3. Melatonin level varied considerably and showed a peak during the day (1500 hr) and a nadir during the night (2400 hr). 4. 4. The results suggest that the optic lobe has certain biochemical activities similar to those found in pineal glands of vertebrates. © 1992.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1016/0300-9629(92)90727-8