LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 115

Search options

  1. Article ; Online: The mammalian gastro-intestinal tract is a NOT a major extra-pineal source of melatonin.

    Kennaway, David J

    Journal of pineal research

    2023  Volume 75, Issue 4, Page(s) e12906

    Abstract: In 1992, a paper reported that the melatonin content of the rat duodenum was 24 000 ± 2000 pg/g tissue (range: 4000-100 000 pg/g) while the pineal melatonin content was 580 000 ± 36 000 pg/g. The data has been used for the last 30 years to infer that the ...

    Abstract In 1992, a paper reported that the melatonin content of the rat duodenum was 24 000 ± 2000 pg/g tissue (range: 4000-100 000 pg/g) while the pineal melatonin content was 580 000 ± 36 000 pg/g. The data has been used for the last 30 years to infer that the gut produces 400 hundred times more melatonin than the pineal gland and that it is the source of plasma melatonin during the daytime. No-one has ever challenged the statement. In this review, evidence is summarised from the literature that pinealectomy eliminates melatonin from the circulation and that studies to the contrary have relied upon poorly validated immunoassays that overstate the levels. Similarly studies that have reported increases in plasma melatonin following tryptophan administration failed to account for cross reactivity of tryptophan and its metabolites in immunoassays. The most extraordinary observation from the literature is that in those studies that have measured melatonin in the gut since 1992, the tissue content is vastly lower than the original report, even when the methodology used could be overestimating the melatonin content due to cross reactivity. Using the more contemporary results we can calculate that rather than a 400:1 ratio of duodenum: pineal melatonin, a ratio of 0.05-0.19: 1 is likely. The gut is not a major extra-pineal source of melatonin; indeed it may well not produce any.
    MeSH term(s) Rats ; Animals ; Melatonin/metabolism ; Pineal Gland/metabolism ; Tryptophan/metabolism ; Circadian Rhythm ; Mammals/metabolism
    Chemical Substances Melatonin (JL5DK93RCL) ; Tryptophan (8DUH1N11BX)
    Language English
    Publishing date 2023-08-31
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 632697-3
    ISSN 1600-079X ; 0742-3098
    ISSN (online) 1600-079X
    ISSN 0742-3098
    DOI 10.1111/jpi.12906
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 2114: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article ; Online: The dim light melatonin onset across ages, methodologies, and sex and its relationship with morningness/eveningness.

    Kennaway, David J

    Sleep

    2023  Volume 46, Issue 5

    Abstract: The onset of melatonin secretion, the dim light melatonin onset (DLMO), is a tool for determining the phase of the circadian timing system. Although small studies have investigated the impacts of age and methods of calculating DLMO, there is no DLMO ... ...

    Abstract The onset of melatonin secretion, the dim light melatonin onset (DLMO), is a tool for determining the phase of the circadian timing system. Although small studies have investigated the impacts of age and methods of calculating DLMO, there is no DLMO reference range. In the current study, the saliva DLMO from 3579 participants from 121 published studies and plasma DLMO from 818 healthy controls from 31 studies (aged 3-73 years) were analyzed. In a subset of 53 papers (1749 participants), individual saliva DLMO and Morningness Eveningness Questionaire (MEQ) scores were obtained from authors or mined from publications and a reference range was constructed. Saliva DLMO was earliest in children to 10 years of age and latest around 20 years of age and thereafter advanced with age by 30 min in the oldest participants. Melatonin assay methods and DLMO calculation methods had little effect on the determination of the DLMO. Saliva DLMO was correlated (p < 0.001) with the MEQ score; lower MEQ scores were associated with later DLMO. MEQ scores increased with age, reflecting a tendency toward morningness. An evaluation of 14 saliva DLMO studies of clinically diagnosed patients living with delayed sleep-wake phase disorder (mean ages 20 to 31 years) revealed mean saliva DLMO within the reference range albeit at the late extreme. Peak plasma melatonin levels from 179 studies of healthy participants revealed a high degree of variability within studies and age groups, but only a small decline between the 20 and 50 years and lowest levels after 70 years.
    MeSH term(s) Child ; Humans ; Young Adult ; Adult ; Circadian Rhythm ; Sleep ; Melatonin ; Circadian Clocks ; Surveys and Questionnaires ; Saliva ; Light
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2023-02-16
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 424441-2
    ISSN 1550-9109 ; 0161-8105
    ISSN (online) 1550-9109
    ISSN 0161-8105
    DOI 10.1093/sleep/zsad033
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 1475: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article: Trough Melatonin Levels Have No Physiological or Clinical Relevance.

    Kennaway, David J

    Clinical psychopharmacology and neuroscience : the official scientific journal of the Korean College of Neuropsychopharmacology

    2021  Volume 19, Issue 2, Page(s) 391–392

    Language English
    Publishing date 2021-04-22
    Publishing country Korea (South)
    Document type Journal Article
    ZDB-ID 2211550-X
    ISSN 1738-1088
    ISSN 1738-1088
    DOI 10.9758/cpn.2021.19.2.391
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 6227: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  4. Article ; Online: Can we believe results obtained from plasma melatonin ELISA kits?

    Kennaway, David J

    Chronobiology international

    2021  Volume 38, Issue 4, Page(s) 616–619

    MeSH term(s) Circadian Rhythm ; Enzyme-Linked Immunosorbent Assay ; Melatonin
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2021-03-04
    Publishing country England
    Document type Letter
    ZDB-ID 998996-1
    ISSN 1525-6073 ; 0742-0528
    ISSN (online) 1525-6073
    ISSN 0742-0528
    DOI 10.1080/07420528.2021.1886112
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 2068: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  5. Article ; Online: Measuring morning melatonin levels with plasma melatonin ELISA kits is a poor choice on two levels.

    Kennaway, David J

    Journal of pineal research

    2021  Volume 72, Issue 1, Page(s) e12773

    MeSH term(s) Circadian Rhythm ; Enzyme-Linked Immunosorbent Assay ; Melatonin
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2021-10-27
    Publishing country England
    Document type Journal Article ; Comment
    ZDB-ID 632697-3
    ISSN 1600-079X ; 0742-3098
    ISSN (online) 1600-079X
    ISSN 0742-3098
    DOI 10.1111/jpi.12773
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 2114: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  6. Article ; Online: What do we really know about the safety and efficacy of melatonin for sleep disorders?

    Kennaway, David J

    Current medical research and opinion

    2021  Volume 38, Issue 2, Page(s) 211–227

    Abstract: Melatonin is a hormonal product of the pineal gland, a fact that is often forgotten. Instead it is promoted as a dietary supplement that will overcome insomnia, as an antioxidant and as a prescription only drug in most countries outside the United States ...

    Abstract Melatonin is a hormonal product of the pineal gland, a fact that is often forgotten. Instead it is promoted as a dietary supplement that will overcome insomnia, as an antioxidant and as a prescription only drug in most countries outside the United States of America and Canada. The aim of this review is to step back and highlight what we know about melatonin following its discovery 60 years ago. What is the role of endogenous melatonin; what does melatonin do to sleep, body temperature, circadian rhythms, the cardiovascular system, reproductive system, endocrine system and metabolism when administered to healthy subjects? When used as a drug/dietary supplement, what safety studies have been conducted? Can we really say melatonin is safe when it has not been systematically studied and many studies show interactions with a wide range of physiological processes? Finally the results of studies investigating the efficacy of melatonin as a drug to alleviate insomnia are critically evaluated. In summary, melatonin is an endogenous pineal gland hormone with specific physiological functions in animals and humans, with its primary role in humans to maintain synchrony of sleep with the day/night cycle. When administered as a drug it affects a wide range of physiological systems and has clinically important drug interactions. With respect to efficacy for treating sleep disorders, melatonin can advance the time of sleep onset but the effect is modest and variable. In children with neurodevelopmental disabilities melatonin appears to have the greatest impact on sleep onset but little effect on sleep efficiency.
    MeSH term(s) Animals ; Circadian Rhythm/physiology ; Humans ; Melatonin/adverse effects ; Melatonin/metabolism ; Sleep ; Sleep Initiation and Maintenance Disorders/drug therapy ; Sleep Wake Disorders/drug therapy
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2021-11-24
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 80296-7
    ISSN 1473-4877 ; 0300-7995
    ISSN (online) 1473-4877
    ISSN 0300-7995
    DOI 10.1080/03007995.2021.2000714
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 955: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  7. Article ; Online: Melatonin insufficiency in the follicular fluid of aged mice; is it real?

    Kennaway, David J

    Redox biology

    2020  Volume 38, Page(s) 101829

    MeSH term(s) Aneuploidy ; Animals ; Female ; Follicular Fluid ; Maternal Age ; Melatonin ; Mice ; Oocytes
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2020-12-13
    Publishing country Netherlands
    Document type Letter ; Comment
    ZDB-ID 2701011-9
    ISSN 2213-2317 ; 2213-2317
    ISSN (online) 2213-2317
    ISSN 2213-2317
    DOI 10.1016/j.redox.2020.101829
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  8. Article ; Online: Melatonin measurement in epilepsy; are the assays letting us down?

    Kennaway, David J

    Epilepsy & behavior : E&B

    2020  Volume 114, Issue Pt A, Page(s) 107594

    MeSH term(s) Child ; Epilepsy/diagnosis ; Humans ; Melatonin ; Seizures
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2020-11-25
    Publishing country United States
    Document type Letter ; Comment
    ZDB-ID 2010587-3
    ISSN 1525-5069 ; 1525-5050
    ISSN (online) 1525-5069
    ISSN 1525-5050
    DOI 10.1016/j.yebeh.2020.107594
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 5289: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  9. Article ; Online: Melatonin rich foods in our diet: food for thought or wishful thinking?

    Kennaway, David J

    Food & function

    2020  Volume 11, Issue 11, Page(s) 9359–9369

    Abstract: Melatonin continues to generate interest in the scientific community and the general public. In recent years, there has been growing interest in the possibility that melatonin present in human foods may have physiological effects. This has led to the ... ...

    Abstract Melatonin continues to generate interest in the scientific community and the general public. In recent years, there has been growing interest in the possibility that melatonin present in human foods may have physiological effects. This has led to the promotion of "melatonin-rich" foods and "phyto-melatonin". The night time secretion of endogenous melatonin from the pineal gland provides a daily circadian signal which is detected by receptors in various tissues. In animals the changing circadian pattern of melatonin secretion across seasons is important to them to program their reproductive behaviours to ensure optimal reproductive success, while in humans it probably plays a prominent role in anchoring sleep to the night period. When melatonin is administered in non-physiological, milligram amounts to humans, the onset of sleep can be manipulated and in larger doses anti-oxidant properties may emerge. Melatonin-rich foods are considered in this context too, but the question remains whether the amounts of melatonin in the food can be expected to be high enough to realistically change sleep or have antioxidant properties. In this review, papers reporting the effects of ingestion of melatonin-rich food on plasma or saliva melatonin or its urinary metabolite are critically evaluated. Unfortunately many of the papers are compromised by poor experimental design and assay methodologies and uncritical evaluation of results. The conclusion drawn from this review is that it is wishful thinking to expect that the amount of melatonin in "melatonin-rich" foods will impact on sleep or have any other physiological impact.
    MeSH term(s) Diet ; Functional Food ; Humans ; Melatonin ; Sleep
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2020-11-10
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2612033-1
    ISSN 2042-650X ; 2042-6496
    ISSN (online) 2042-650X
    ISSN 2042-6496
    DOI 10.1039/d0fo02563a
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Bonn / Germany

    Z 7872: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  10. Article ; Online: Measuring melatonin by immunoassay.

    Kennaway, David J

    Journal of pineal research

    2020  Volume 69, Issue 1, Page(s) e12657

    Abstract: The pineal gland hormone melatonin continues to be of considerable interest to biomedical researchers. Of particular interest is the pattern of secretion of melatonin in relation to sleep timing as well as its potential role in certain diseases. ... ...

    Abstract The pineal gland hormone melatonin continues to be of considerable interest to biomedical researchers. Of particular interest is the pattern of secretion of melatonin in relation to sleep timing as well as its potential role in certain diseases. Measuring melatonin in biological fluids such as blood and saliva presents particular methodological challenges since the production and secretion of the hormone are known to be extremely low during the light phase in almost all situations. Active secretion only occurs around the time of lights out in a wide range of species. The challenge then is to develop practical high-throughput assays that are sufficiently sensitive and accurate enough to detect levels of melatonin less than 1 pg/mL in biological fluids. Mass spectrometry assays have been developed that achieve the required sensitivity, but are really not practical or even widely available to most researchers. Melatonin radioimmunoassays and ELISA have been developed and are commercially available. But the quality of the results that are being published is very variable, partly not only because of poor experimental designs, but also because of poor assays. In this review, I discuss issues around the design of studies involving melatonin measurement. I then provide a critical assessment of 21 immunoassay kits marketed by 11 different companies with respect to validation, specificity and sensitivity. Technical managers of the companies were contacted in an attempt to obtain information not available online or in kit inserts. A search of the literature was also conducted to uncover papers that have reported the use of these assays, and where possible, both daytime and night-time plasma or saliva melatonin concentrations were extracted and tabulated. The results of the evaluations are disturbing, with many kits lacking any validation studies or using inadequate validation methods. Few assays have been properly assessed for specificity, while others report cross-reaction profiles that can be expected to result in over estimation of the melatonin levels. Some assays are not fit for purpose because they are not sensitive enough to determine plasma or saliva DLMO of 10 and 3 pg/mL, respectively. Finally, some assays produce unrealistically high daytime melatonin levels in humans and laboratory animals in the order of hundreds of pg/mL. In summary, this review provides a comprehensive and unique assessment of the current commercial melatonin immunoassays and their use in publications. It provides researchers new to the field with the information they need to design valid melatonin studies from both the perspective of experimental/clinical trial design and the best assay methodologies. It will also hopefully help journal editors and reviewers who may not be fully aware of the pitfalls of melatonin measurement make better informed decisions on publication acceptability.
    MeSH term(s) Body Fluids/metabolism ; Circadian Rhythm ; Enzyme-Linked Immunosorbent Assay ; Humans ; Melatonin/analysis ; Melatonin/metabolism ; Pineal Gland/metabolism ; Radioimmunoassay
    Chemical Substances Melatonin (JL5DK93RCL)
    Language English
    Publishing date 2020-04-27
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 632697-3
    ISSN 1600-079X ; 0742-3098
    ISSN (online) 1600-079X
    ISSN 0742-3098
    DOI 10.1111/jpi.12657
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 2114: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top