title: Age-associated changes in pineal serotonin N-acetyltransferase activity and melatonin content in the male gerbil.
abstract: Pineal serotonin N-acetyltransferase (NAT) activity and melatonin content were measured in 2- and 15-month old male gerbils at various times over a 24h light:dark cycle (LD 14:10). A nocturnal increase over the low daytime values in NAT activity and melatonin content was noted in both 2- and 15-month old gerbils, suggesting the continued existence of a circadian rhythm in each of these biochemical parameters of pineal secretory function at least until 15-months of age. Notable differences in the levels of NAT activity and melatonin content between 2- and 15-month old gerbils included (1) a phase shift in peak NAT activity and melatonin content in 15-month old versus 2-month old gerbils and (2) a latent decrease in NAT activity in 15-month old gerbils after the onset of the light period relative to that in 2-month old gerbils.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism*; D000375:Aging; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D003624:Darkness; D005849:Gerbillinae; D008027:Light; D008297:Male; D008550:Melatonin / Q000032:analysis*; D010507:Periodicity; D010870:Pineal Gland / Q000032:analysis / Q000201:enzymology*
chemical_list: D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin