<abstract xmlns="http://www.w3.org/1999/xhtml"> Objective. Melatonin is a hormone predominantly synthesized and secreted during the night by the pineal gland. Artificial light at night, especially its blue part, acutely suppresses the melatonin production. Th e aim of the present study was to find out, whether an intense blue light phototherapy of severe hyperbilirubinemia, may suppress the melatonin production during the night when the eyes will be properly protected by a sleep mask.Methods. The main melatonin metabolite, 6-sulphatoxymelatonin was measured in urine in a nine-year old boy suffering from the Crigler-Najjar syndrome type I. The boy was treated during the sleep period with an intense blue light (to 1800 lx) 10 h/day, since his birth. During the phototherapy, his eyes were protected with a sleep mask. The concentration of 6-sulphatoxymelatonin was determined in the first morning urine and urine collected afternoon during the six days. The patient was exposed to phototherapy for three nights, two nights without and the last one with the treatment. The control urine samples were obtained from 8 healthy nine-year old boys. The level of 6-sulphatoxymelatonin was measured by radioimmunoassay and the data were normalized to urinary creatinine.Results. A distinct melatonin production rhythm was found and 6-sulphatoxymelatonin concentration in urine of the patient was comparable with the values obtained by the control group. No differences in 6-sulphatoxymelatonin levels were found between the nights with and without the phototherapy applied.Conclusions. We conclude that the whole night treatment of hyperbilirubinemia with intense blue light has negligible side effect on the rhythmic melatonin production, when the eyes are sufficiently protected by the sleep mask.</abstract>

Objective. Melatonin is a hormone predominantly synthesized and secreted during the night by the pineal gland. Artificial light at night, especially its blue part, acutely suppresses the melatonin production. Th e aim of the present study was to find out, whether an intense blue light phototherapy of severe hyperbilirubinemia, may suppress the melatonin production during the night when the eyes will be properly protected by a sleep mask.Methods. The main melatonin metabolite, 6-sulphatoxymelatonin was measured in urine in a nine-year old boy suffering from the Crigler-Najjar syndrome type I. The boy was treated during the sleep period with an intense blue light (to 1800 lx) 10 h/day, since his birth. During the phototherapy, his eyes were protected with a sleep mask. The concentration of 6-sulphatoxymelatonin was determined in the first morning urine and urine collected afternoon during the six days. The patient was exposed to phototherapy for three nights, two nights without and the last one with the treatment. The control urine samples were obtained from 8 healthy nine-year old boys. The level of 6-sulphatoxymelatonin was measured by radioimmunoassay and the data were normalized to urinary creatinine.Results. A distinct melatonin production rhythm was found and 6-sulphatoxymelatonin concentration in urine of the patient was comparable with the values obtained by the control group. No differences in 6-sulphatoxymelatonin levels were found between the nights with and without the phototherapy applied.Conclusions. We conclude that the whole night treatment of hyperbilirubinemia with intense blue light has negligible side effect on the rhythmic melatonin production, when the eyes are sufficiently protected by the sleep mask.

Intense blue light therapy during the night-time does not suppress the rhythmic melatonin biosynthesis in a young boy

PhD., Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava,

1st Department of Pediatrics, University Children’s Hospital, Bratislava,

Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava,

Endocrine Regulations

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Objective. Melatonin is a hormone predominantly synthesized and secreted during the night by the pineal gland. Artificial light at night, especially its blue...

Intense blue light therapy during the night-time does not suppress the rhythmic melatonin biosynthesis in a young boy

Published Online: Feb 17, 2017

Page range: 31 - 34

DOI: https://doi.org/10.1515/enr-2017-0004

Keywords
melatonin, 6 sulphatoxymelatonin, phototherapy, blue light, hyperbilirubinemia

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Intense blue light therapy during the night-time does not suppress the rhythmic melatonin biosynthesis in a young boy

Published Online: Feb 17, 2017

Page range: 31 - 34

DOI: https://doi.org/10.1515/enr-2017-0004

Keywordsmelatonin, 6 sulphatoxymelatonin, phototherapy, blue light, hyperbilirubinemia

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
melatonin, 6 sulphatoxymelatonin, phototherapy, blue light, hyperbilirubinemia