The amplitude of endogenous melatonin production is not affected by melatonin treatment in humans

1997 ◽  
Vol 22 (1) ◽  
pp. 42-44 ◽  
Author(s):  
Miki Matsumoto ◽  
Robert L. Sack ◽  
Mary L. Blood ◽  
Alfred J. Lewy
Keyword(s):  
Melatonin Treatment ◽  
Melatonin Production ◽  
Endogenous Melatonin

Effects of daytime melatonin infusion in young adults

1998 ◽  
Vol 275 (1) ◽  
pp. E19-E26
Author(s):  
Cameron J. Van Den Heuvel ◽  
David J. Kennaway ◽  
Drew Dawson
Keyword(s):  
Young Adults ◽  
Physiological Response ◽  
Physiological Responses ◽  
Bed Rest ◽  
Hand Temperature ◽  
Melatonin Administration ◽  
Significant Attenuation ◽  
Steady State Levels ◽  
Melatonin Production ◽  
Endogenous Melatonin

Daytime oral melatonin typically exerts soporific and thermoregulatory effects; however, it is not clear whether these effects reflect the normal physiological response to endogenous nocturnal melatonin production. We infused melatonin at doses that produced physiological and supraphysiological steady-state levels in 24 young adults during two daytime bed rest protocols. From 1000 to 1630, subjects were infused intravenously with saline or melatonin in counterbalanced order. Each group of eight subjects received melatonin (and saline) infusions at one dose rate: 0.04 μg ⋅ h−1 ⋅ kg body wt−1 (low), 0.08 μg ⋅ h−1 ⋅ kg−1(medium), or 8.0 μg ⋅ h−1 ⋅ kg−1(high). Low and medium melatonin infusions produced plasma and saliva levels within the normal nocturnal range observed in young adults. These levels were not associated with any changes in rectal, hand, forehead, or tympanic temperatures or with subjective sleepiness. High melatonin produced supraphysiological plasma and saliva levels and was associated with a significant attenuation in the daytime increase in rectal temperature, significantly increased hand temperature, and greater sleepiness. It is not yet clear whether the thermoregulatory and soporific effects of daytime supraphysiological melatonin administration are equivalent to the physiological responses to endogenous melatonin.

Melatonin treatment promotes endogenous melatonin accumulation and triggers GABA shunt pathway activity in tomato fruits during cold storage

2019 ◽  
Vol 254 ◽  
pp. 222-227 ◽  
Author(s):  
Yavar Sharafi ◽  
Morteza Soleimani Aghdam ◽  
Zisheng Luo ◽  
Abbasali Jannatizadeh ◽  
Farhang Razavi ◽  
...  
Keyword(s):  
Cold Storage ◽  
Melatonin Treatment ◽  
Tomato Fruits ◽  
Gaba Shunt ◽  
Pathway Activity ◽  
Shunt Pathway ◽  
Endogenous Melatonin

Physiological Ischemia/Reperfusion Phenomena and Their Relation to Endogenous Melatonin Production: An Hypothesis

Endocrine ◽  
2005 ◽  
Vol 27 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Dun-Xian Tan ◽  
Lucien C. Manchester ◽  
Rosa M. Sainz ◽  
Juan C. Mayo ◽  
Josefa León ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Melatonin Production ◽  
Endogenous Melatonin

Longitudinal Associations between Endogenous Melatonin Production and Reported Sleep Duration from Childhood to Early Adulthood

2010 ◽  
Vol 74 (6) ◽  
pp. 390-398 ◽  
Author(s):  
Katharina Diethelm ◽  
Lars Libuda ◽  
Katja Bolzenius ◽  
Barbara Griefahn ◽  
Anette E. Buyken ◽  
...  
Keyword(s):  
Sleep Duration ◽  
Early Adulthood ◽  
Longitudinal Associations ◽  
Melatonin Production ◽  
Endogenous Melatonin

scholarly journals Melatonin in animal models

2003 ◽  
Vol 5 (4) ◽  
pp. 343-352
Keyword(s):  
Circadian Clock ◽  
Melatonin Receptors ◽  
Cellular Mechanisms ◽  
Exact Role ◽  
Physiological Processes ◽  
Timing System ◽  
Circadian Organization ◽  
Melatonin Production ◽  
Endogenous Melatonin

Melatonin is a hormone synthesized and secreted during the night by the pineal gland. Its production is mainly driven by the Orcadian clock, which, in mammals, is situated in the suprachiasmatic nucleus of the hypothalamus. The melatonin production and release displays characteristic daily (nocturnal) and seasonal patterns (changes in duration proportional to the length of the night) of secretion. These rhythms in circulating melatonin are strong synchronizers for the expression of numerous physiological processes. 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. The exact role of the hormone in the diurnal (Orcadian) timing system remains to be determined. However, exogenous melatonin has been shown to affect the circadian clock. The molecular and cellular mechanisms involved in this well-characterized "chronobiotic" effect have also begun to be characterized. 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. A better understanding of such "chronobiotic" effects of melatonin will allow clarification of the role of endogenous melatonin in circadian organization.

scholarly journals Phenylalanine 4-Hydroxylase Contributes to Endophytic Bacterium Pseudomonas fluorescens’ Melatonin Biosynthesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Jian Jiao ◽  
Yan Xia ◽  
Yingli Zhang ◽  
Xueli Wu ◽  
Chonghuai Liu ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Pseudomonas Fluorescens ◽  
Current Knowledge ◽  
Endophytic Bacterium ◽  
Significant Decline ◽  
Hydroxylase Activity ◽  
Abiotic Stressors ◽  
Melatonin Production ◽  
Endogenous Melatonin

Melatonin acts both as an antioxidant and as a growth regulatory substance in plants. Pseudomonas fluorescens endophytic bacterium has been shown to produce melatonin and increase plant resistance to abiotic stressors through increasing endogenous melatonin. However, in bacteria, genes are still not known to be melatonin-related. Here, we reported that the bacterial phenylalanine 4-hydroxylase (PAH) may be involved in the 5-hydroxytryptophan (5-HTP) biosynthesis and further influenced the subsequent production of melatonin in P. fluorescens. The purified PAH protein of P. fluorescens not only hydroxylated phenylalanine but also exhibited l-tryptophan (l-Trp) hydroxylase activity by converting l-Trp to 5-HTP in vitro. However, bacterial PAH displayed lower activity and affinity for l-Trp than l-phenylalanine. Notably, the PAH deletion of P. fluorescens blocked melatonin production by causing a significant decline in 5-HTP levels and thus decreased the resistance to abiotic stress. Overall, this study revealed a possible role for bacterial PAH in controlling 5-HTP and melatonin biosynthesis in bacteria, and expanded the current knowledge of melatonin production in microorganisms.

Monosodium glutamate administration early in life alters pineal melatonin nocturnal profile in adulthood

2021 ◽  
Vol 4 (1) ◽  
pp. 99-114
Author(s):  
Janaína B Garcia ◽  
Fernanda G Do Amaral ◽  
Daniela C Buonfiglio ◽  
Rafaela FA Vendrame ◽  
Patrícia L Alves ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Pineal Gland ◽  
Serum Insulin ◽  
Monosodium Glutamate ◽  
Female Rats ◽  
Pineal Melatonin ◽  
Melatonin Synthesis ◽  
Male And Female Rats ◽  
Melatonin Production

The pineal gland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes.  Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different aged male and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.

Melatonin: Protection of the Intervertebral Disc

2019 ◽  
Vol 2 (3) ◽  
pp. 1-9
Author(s):  
Russel J Reiter ◽  
Sergio Rosales-Corral ◽  
Ramaswamy Sharma
Keyword(s):  
Intervertebral Disc ◽  
Molecular Mechanisms ◽  
Intervertebral Discs ◽  
Lumbar Pain ◽  
Low Back ◽  
Work Time ◽  
Protective Actions ◽  
Aging Populations ◽  
Definition Of ◽  
Endogenous Melatonin

     Low back pain (lumbar pain) due to injury of or damage to intervertebral discs is common in all societies.  The loss of work time as a result of this problem is massive.  Recent research suggests that melatonin may prevent or counteract intervertebral disc damage. This may be especially relevant in aging populations given that endogenous melatonin, in most individuals, dwindles with increasing age. The publications related to melatonin and its protection of the intervertebral disc are reviewed herein, including definition of some molecular mechanisms that account for melatonin’s protective actions. 

Desynchronosis markers in risk assessment of metabolic syndrome development

2019 ◽  
Vol 1 (4) ◽  
pp. 21-26 ◽  
Author(s):  
O. V. Bobko ◽  
O. V. Tikhomirova ◽  
N. N. Zybina ◽  
O. A. Klitsenko
Keyword(s):  
Risk Assessment ◽  
Metabolic Syndrome ◽  
Threshold Values ◽  
Fat Tissue ◽  
Diurnal Dynamics ◽  
Laboratory Markers ◽  
Dyscirculatory Encephalopathy ◽  
Melatonin Production ◽  
Pai 1 ◽  
Logistic Regression Equation

The objective of the study is to show significance of desynchronosis laboratory markers in risk assessment of metabolic syndrome (MS) development. Materials and Methods. There were examined 98 men, aged 43-88, diagnosed with dyscirculatory encephalopathy showing one and more risk factors for development of cardiovascular diseases. They were divided into 2 groups according to the international guidelines of 2009: with MS (n = 61) and without MS (n = 37). Parameters of fats, glucose metabolism, inflammatory mediators, fat tissue metabolism markers, melatonin metabolite excretion (6-sulfatoxymelatonin) were defined in blood serum and urine. Results. The article presents data on changes in leptin, adiponectin, PAI-1, testosterone production and 6-sulfatoxymela-tonin excretion in patients with MS. There are calculated threshold values of these markers definitely increasing MS risk and logistic regression equation which allows assessing MS risk for an individual patient. Conclusion. Detected disorders of melatonin synthesis diurnal dynamics in patients with MS and interconnection between melatonin production and adiponectin, leptin, PAI-1, testosterone synthesis allow considering these parameters as desynchronosis markers significant for MS development.

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