Pineal gland hormones

Interestingly, melatonin, the human pineal gland hormone, has been detected in scullcap at a concentration of 0.09 pg/g (Murch et al., 1997). 

Wiesenberg, I., Missbach, M., Kahlen, J. P., Schrader, M., and Carlberg, C. (1995) Transcriptional activation of the nuclear receptor RZR alpha by the pineal gland hormone melatonin and identification of CGP 52608 as a synthetic ligand. Nucleic Acids Res. 23, 327-333. 

Melatonin (V-acetyl-5-methoxytryptamine) is a pineal gland hormone which aggregates melanin granules in the dermal melanophores and is capable of lightening the color of frog melanocytes by reversing the darkening action of MSH, ACTH, and caffeine (116, 149). Its effect on the human and other mammalian melanocytes is, however, questionable (253). 

A hormone synthesized in the pineal gland Certain mental disorders are be lieved to be related to sero tonin levels in the brain )... 

However, despite its enormous importance to human physiology, no pharmacological compounds targeting the components of the circadian clock system have been identified to date. There are, nevertheless, two therapeutic approaches that are currently used for treatment of circadian-related disorders - full-spectrum and bright light therapy and melatonin therapy. Melatonin is a hormone that is produced by the pineal gland in... 

Figure 22.1 Pathways projecting to and from the suprachiasmatic nucleus (SCN). Inputs from photoreceptors in the retina help to reset the circadian clock in response to changes in the light cycle. Other inputs derive from the lateral geniculate complex and the serotonergic, Raphe nuclei and help to reset the SCN in response to non-photic stimuli. Neurons in the SCN project to the hypothalamus, which has a key role in the regulation of the reproductive cycle, mood and the sleep-waking cycle. These neurons also project to the pineal gland which shows rhythmic changes in the rate of synthesis and release of the hormone, melatonin...

Dietary Supplements. In the past 10 years, melatonin, available as a dietary supplement from health food stores or over the Internet, has become a popular sleep agent. Melatonin is a hormone produced by the pineal gland at peak levels during the night. It is believed to help regulate the 24 hour circadian sleep-wake cycle. 

Melatonin is A-acetyl-5-methoxytryptamine, a simple derivative of serotonin. It is a natural hormone secreted by the pineal gland in the brain during the hours of darkness. It is involved in controlling the body s day-night... 

In addition to its presumed role as a neurotransmitter within the brain, serotonin is synthesized in the pineal gland, where it is a precursor for the synthesis of melatonin, a hormone that influences endocrine activity, presumably by an action within the hypothalamus. 

Reiter RJ The pineal gland and its neurohormone melatonin basic aspects, in Hormonal Modulation of Brain and Behavior. Edited by Halbreich U. Washington, DC, American Psychiatric Press [in press b)... 

Melatonin is found in many areas of many animals. It is involved in the skin coloration of amphibians, and in the thermal or motor regulation in some higher animals. Its major regulatory role is in response to light and, in man, is the major hormone produced by the pineal gland. 

Melatonin—A hormone produced by the brain s pineal gland and thought to promote sleep. 

The pineal gland appears also to play a role in maintaining the mammalian circadian cycle.1081-1083 The concentration of the pineal hormone melatonin (Fig. 27-11) as well as its precursor N-acetylserotonin and the enzyme serotonin N-acetyltransferase (Eq. 30-4) all fluctuate far more than do the concentrations of other metabolites during the 24-h cycle. These metabolites increase over 10-fold concentration at night and decrease by day. During the daytime the serotonin N-acyltransferase, which forms the precursor, is rapidly... 

This hormone of the pineal gland, 215, has been labelled201 with carbon-11 to study its role in health, depressive illness and internal clock disorders (cyclic events of life in mammals). The new labelling reagent [nC]acetyl chloride has been used as shown... 

Melatonin (lV-acetyl-5-methoxytryptamine) is a neuro-hormone secreted by the pineal gland from the amino acid precursor [,-tryptophan. Its endogenous secretion is photosensitive and has a circadian rhythm—plasma melatonin concentrations are highest at night in both diurnal and nocturnal animals, and fall with age (1). The nocturnal melatonin peak coincides with a drop in body temperature and increased sleepiness in healthy humans. Oral melatonin has a short half-life (30-50 minutes) and extensive first-pass metabolism. Its clearance is reduced in severe liver disease (2). 

Oxytocin is a lessor known hormone produced in several areas of the body including the testes, pancreas, pineal gland, thymus, adrenal glands, and ovaries. So it would seem apparent that this is an important hormone. You don t know the half of it yet. 

Some parts of the brain, like the cerebral cortex, are much more highly evolved in humans than in other animals. The pineal gland, however, is a very basic organ that first evolved in primitive species. It is found in lampreys, fish, amphibians, and reptiles, as well as in mammals. The hormone melatonin has also been found in insects and plants. 

The production of melatonin varies over the course of a day. Darkness stimulates the pineal gland to produce melatonin, while the presence of light inhibits the release of this hormone. Melatonin levels are so low during the day lime that they are almost immeasurable. The amount of melatonin starts to increase around 9 p.m. or 10 p.m. 

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