Reciprocal day/night relationship between serotonin oxidation and N-acetylation products in the rat pineal gland.
Pineal tryptophan, serotonin [5-hydroxytryptamine (5-HT)], N-acetylserotonin, melatonin, 5-hydroxyindoleacetic acid, 5-hydroxytryptophol, 5-methoxytryptophol, and 5-methoxyindoleacetic acid were measured by high pressure liquid chromatography with electrochemical detection. A complete analysis required less than the equivalent of two rat pineal glands. Samples were obtained at eight time points. A reciprocal physiological relationship was found between oxidation and N-acetylation products of 5-HT. 5-HT and the oxidation products 5-hydroxyindoleacetic acid, 5-hydroxytryptophol, 5-methoxytryptophol, and 5-methoxyindoleacetic acid decreased at night, when the N-acetylation products N-acetylserotonin and melatonin increased. These observations are consistent with the hypothesis that circadian changes in the N-acetylation of 5-HT by indoleamine N-acetyltransferase is the major factor controlling circadian changes in the amounts of 5-HT, and 5-HT oxidation and N-acetylation products in the rat pineal gland.
D000107:Acetylation; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002940:Circadian Rhythm; D006897:Hydroxyindoleacetic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D010870:Pineal Gland / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*
D007211:Indoles; D012701:Serotonin; C001736:5-methoxyindoleacetic acid; D006897:Hydroxyindoleacetic Acid; C002465:methoxytryptophol