title: Correlations of serotonin and its metabolites in individual rat pineal glands over light:dark cycles and after acute light exposure.
abstract: Profiles of pineal indolealkylamines were estimated by high performance liquid chromatography and were correlated in individual glands of male rats sacrificed over several light:dark cycles and after acute exposure to light at night. A significant and positive correlation of 5HIAA vs 5HT in individual glands over both normal and experimental lighting conditions suggested that oxidative deamination is not a major factor in photic regulation of pineal 5HT levels and that the formation of 5HIAA is dependent on substrate availability. Regression analysis of other indole constituents revealed that there was a positive and significant correlation between 5HT vs N-acetylserotonin, but not between 5HT vs melatonin and N-acetylserotonin vs melatonin in individual glands during the dark phase of a light:dark cycle. We propose that this effect may be related to a pulsatile release of melatonin into the blood stream and is the result of sampling glands at different stages in the storage/release of melatonin.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002940:Circadian Rhythm; D006897:Hydroxyindoleacetic Acid / Q000096:biosynthesis; D008027:Light; D008297:Male; D008550:Melatonin / Q000096:biosynthesis / Q000378:metabolism; D010870:Pineal Gland / Q000378:metabolism* / Q000528:radiation effects; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D008550:Melatonin; C006389:N-acetylserotonin