![]() En los mamiferos, el papel de la melatonina en el control de la estacionalidad está bien documentado, y los sitios y mecanismos de acción involucrados se están comenzando a identificar, El papel exacto de la hormona en el sistema de ritmo diurno (circadiano) debe ser determinado. Su producción es controlada principalmente por el reloj circadiano, el cual en los mamiferos está situado en el núcleo supraquiasmático del hipotálamo, La producción y liberación de melatonina tiene perfiles de secreción caracteristicos tanto diarios (nocturnos) como estacionales (cambios en la duración proporcionales a la duración de la noche), Estos ritmos en la melatonina circulante son fuertes sincronizadores para la expresión de numerosos procesos fisiológicos. La melatonina es una hormona que es sintetizada y secretada durante la noche por la glándula pineal. A better understanding of such “chronobiotic” effects of melatonin will allow clarification of the role of endogenous melatonin in circadian organization. The circadian clock itself appears to be an important site for the entrapment effect of melatonin and the presence of melatonin receptors appears to be a prerequisite. The molecular and cellular mechanisms involved in this well-characterized “chronobiotic” effect have also begun to be characterized. ![]() However, exogenous melatonin has been shown to affect the circadian clock. The exact role of the hormone in the diurnal (Orcadian) timing system remains to be determined. In mammals, the role of melatonin in the control of seasonality is well documented, and the sites and mechanisms of action involved are beginning to be identified. These rhythms in circulating melatonin are strong synchronizers for the expression of numerous physiological processes. The melatonin production and release displays characteristic daily (nocturnal) and seasonal patterns (changes in duration proportional to the length of the night) of secretion. Its production is mainly driven by the Orcadian clock, which, in mammals, is situated in the suprachiasmatic nucleus of the hypothalamus. ![]() ![]() Melatonin is a hormone synthesized and secreted during the night by the pineal gland. ![]()
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