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Titolo:
Identification of highly elevated levels of melatonin in bone marrow: its origin and significance
Autore:
Tan, DX; Manchester, LC; Reiter, RJ; Qi, WB; Zhang, M; Weintraub, ST; Cabrera, J; Sainz, RM; Mayo, JC;
Indirizzi:
Univ Texas, Hlth Sci Ctr, Dept Cellular & Struct Biol, San Antonio, TX 78284 USA Univ Texas San Antonio TX USA 78284 truct Biol, San Antonio, TX 78284 USA Univ Texas, Hlth Sci Ctr, Dept Biochem, San Antonio, TX 78284 USA Univ Texas San Antonio TX USA 78284 pt Biochem, San Antonio, TX 78284 USA
Titolo Testata:
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
fascicolo: 1-2, volume: 1472, anno: 1999,
pagine: 206 - 214
SICI:
0304-4165(19991018)1472:1-2<206:IOHELO>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
PINEAL HORMONE MELATONIN; SEROTONIN N-ACETYLTRANSFERASE; IN-VIVO; CARCINOGEN SAFROLE; OXIDATIVE DAMAGE; RAT; RADIOIMMUNOASSAY; MICE; IMMUNOREACTIVITY; GENOTOXICITY;
Keywords:
melatonin; bone marrow; free radicals; antioxidant; immunocompetence;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Reiter, RJ Univ Texas, Hlth Sci Ctr, Dept Cellular & Struct Biol, 7703 Floyd Curl Dr,San Antonio, TX 78284 USA Univ Texas 7703 Floyd Curl Dr San Antonio TX USA 78284 8284 USA
Citazione:
D.X. Tan et al., "Identification of highly elevated levels of melatonin in bone marrow: its origin and significance", BBA-GEN SUB, 1472(1-2), 1999, pp. 206-214

Abstract

Bone marrow is an important tissue in generation of immunocompetent and peripheral blood cells. The progenitors of hematopoietic cells in bone marrowexhibit continuous proliferation and differentiation and they are highly vulnerable to acute or chronic oxidative stress. In this investigation, highly elevated levels of the antioxidant melatonin were identified in rat bonemarrow using immunocytochemistry, radioimmunoassay, high performance liquid chromatography with electrochemical detection and mass spectrometry. Night-time melatonin concentrations (expressed as pg melatonin/mg protein) in the bone marrow of rats were roughly two orders of magnitude higher than those in peripheral blood. Measurement of the activities of the two enzymes (N-acetyltransferase (NAT) and hydroxyindole-O-methoxyltransferase (HIOMT)) which synthesize melatonin from serotonin showed that bone marrow cells havemeasurable NAT activity, but they have very low levels of HIOMT activity (at the one time they were measured), From these studies we could not definitively determine whether melatonin was produced in bone marrow cells or elsewhere. To investigate the potential pineal origin of bone marrow melatonin, long-term (8-month) pinealectomized rats were used to ascertain if the pineal gland is the primary source of this antioxidant. The bone marrow of pinealectomized rats, however, still exhibited high levels of melatonin. These results indicate that a major portion of the bone marrow's melatonin is of extrapineal origin. Immunocytochemistry clearly showed a positive melatonin reaction intracellularly in bone marrow cells. A melatonin concentratingmechanism in these cells is suggested by these findings and this may involve a specific melatonin binding protein. Since melatonin is an endogenous free radical scavenger and an immune-enhancing agent, the high levels of melatonin in bone marrow cells may provide on-site protection to reduce oxidative damage to these highly vulnerable hematopoietic cells and may enhance the immune capacity of cells such as lymphocytes. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

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Documento generato il 24/09/20 alle ore 23:45:06