title: In vitro effects of 5-hydroxytryptophan, indoleamines and leptin on arylalkylamine N-acetyltransferase (AA-NAT) activity in pineal organ of the fish, Clarias gariepinus (Burchell, 1822) during different phases of the breeding cycle.
abstract: Arylalkylamine N-acetyltransferase (AA-NAT) is the rate-limiting enzyme of melatonin biosynthetic pathway. In vitro effects of 5-hydroxytryptophan (5-HTP) and indoleamines (serotonin, N-acetylserotonin and melatonin) were studied on AA-NAT activity in the pineal organ of the fish, C. gariepinus during different phases of its annual breeding cycle. Further, in vitro effects of leptin on AA-NAT activity in the pineal organ were studied in fed and fasted fishes during summer and winter seasons. Treatments with 5-HTP and indoleamines invariably stimulated pineal AA-NAT activity in a dose-dependent manner during all the phases. However, leptin increased AA-NAT activity in a dose-dependent manner only in the pineal organ of the fed fishes, but not of the fasted fishes irrespective of the seasons.
authors.affiliation: Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793 022, India. gupta@nehu.ac.in
authors.forename: B B P
authors.initials: BB
authors.lastname: Gupta
authors.forename: L
authors.initials: L
authors.lastname: Yanthan
authors.forename: Ksh Manisana
authors.initials: KM
authors.lastname: Singh
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D047068:Arylalkylamine N-Acetyltransferase / Q000378:metabolism*; D001947:Breeding; D002397:Catfishes; D020738:Leptin / Q000494:pharmacology*; D008550:Melatonin / Q000494:pharmacology*; D010870:Pineal Gland / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D011863:Radioimmunoassay; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: D018687:Antidepressive Agents, Second-Generation; D000975:Antioxidants; D020738:Leptin; D017366:Serotonin Receptor Agonists; D012701:Serotonin; D006916:5-Hydroxytryptophan; D047068:Arylalkylamine N-Acetyltransferase; D008550:Melatonin; C006389:N-acetylserotonin