Melatonin secretion regulation

The circadian pattern of pineal NAT activity and consequently melatonin secretion is controlled by the suprachiasmatic nuclei (SCN) as it is abolished by lesions of the SCN, the major circadian oscillator (Klein and Moore 1979). Thus, the environmental L/D cycle acts as the pervasive and pre-eminent Zeitgeber that regulates melatonin synthesis (Scheer and Czeisler 2005). 

Melatonin has been used to regulate the sleep-wake cycle and is used often to treat insomnia. It is not recommended during pregnancy and breast-feeding becanse of a lack of information abont its safety. Lower doses of melatonin (e.g., 0.1-1 mg at bedtime) are effective in initiating sleep higher doses may not improve the hypnotic effect. The rednction in daytime snnUght, which increases melatonin secretion, may exacerbate PMS in the winter this type of seasonal mood disorder may respond to phototherapy. Early sleep deprivation also may help to correct circadian rhythm disturbances in PMDD. ... 

Melatonin. Melatonin (A/-acetyl-5-metlioxytryptaniine) [73-31-4] C 2H gN2O2(250) is secreted from the pineal gland and retina during dark periods of the vertebrate circadian rhythm (65). Melatonin regulates biological rhythms and neuroendocrine function and is formed from serotonin (5-HT). 

Roy, D. Belsham, D. D. (2002). Melatonin receptor activation regulates GnRH gene expression and secretion in GT1-7 GnRH neurons. Signal transduction mechanisms. J. Biol. Chem. 277, 251-8. 

The HPG axis is responsible for the cyclic hormone secretion that regulates and controls ovulation and plays a major role in menstruation-related disorders. The menstrual cycle is characterized by cyclic alterations in the production of gonadal hormones (estradiol and progesterone), pituitary hormones (gonadatropins, prolactin, growth hormone), melatonin, and cortisol and in temperature rhythms. Menstruation-related disorders are likely the result of a complex interaction between ovarian steroids and central neurotransmitters, neurohormones, and neuropeptides. The occurrence of physical... 

Melatonin, a hormone secreted by the pineal gland that regulates circadian rhythms, including wake-sleep cycles, is biosynthesized by a process in which the first step is an enzyme-catalyzed transfer of the acetyl group from sulfur of acetyl coenzyme A to the —NH2 group of serotonin. 

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