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Source, Impact, and Perspective of Light Pollution
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
Essia Hannachi, Yassine Slimani
Stevens’ group hypothesized that exposure to light in the evening may be dangerous and cause breast cancer in developed civilizations through its capacity to destroy the nocturnal creation of melatonin [62]. This supposition is founded on investigations indicating that melatonin impedes the development of breast cancer, while surgical resection of the pineal gland or exposition to steady light promotes the formation of breast tumors in rodents [64]. This hypothesis was further supported by the validation that nocturnal levels of melatonin directly hinder the proliferation of human MCF-7 breast cancer cells in culture [65].
Chronobiology and Human Health
Published in Lisa Heschong, Visual Delight in Architecture, 2021
Indeed, the extremely long tails of these ipRGC nerve cells, their axons, were found to go directly to the brain’s primary controller of circadian rhythms, the suprachiasmatic nucleus, or the SCN for short. The SCN then communicates with many regions of the brain. One important pathway leads to the pineal gland, which produces the hormone melatonin. The pineal gland begins to manufacture melatonin with the onset of dim light in the evening, with concentrations peaking later in the middle of the night and gradually dissipating with the arrival of morning light.
Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The next major subdivision encountered is the diencephalon, consisting mainly of the thalamus, the hypothalamus just below the thalamus, including the posterior part of the pituitary gland, and the pineal gland. The thalamus constitutes about 80% of the diencephalon by volume and processes all sensory signals on their way to the cerebral cortex, with the exception of olfactory signals. It is involved in regulating sleep and wakefulness, arousal, and awareness. Its functions are discussed in Chapter 12. The hypothalamus is a regulatory center for several metabolic, autonomic, and behavioral responses, including body temperature, fluid and electrolytic balance, hunger, thirst, fatigue, sleep, circadian rhythms, sexual activity, and emotional responses such as anger, fear, and pleasure. It controls endocrine function through the pituitary gland. The pineal gland produces melatonin, which regulates the circadian rhythm, that is, the night and day cycle.
A Review of Human Physiological Responses to Light: Implications for the Development of Integrative Lighting Solutions
Published in LEUKOS, 2022
Céline Vetter, P. Morgan Pattison, Kevin Houser, Michael Herf, Andrew J. K. Phillips, Kenneth P. Wright, Debra J. Skene, George C. Brainard, Diane B. Boivin, Gena Glickman
In addition to light’s capacity to shift the circadian phase of various human hormones, light exposure during the biological night can also acutely reduce the high nocturnal levels of circulating melatonin, which is produced and secreted by the pineal gland. While there are substantial inter-individual differences in absolute melatonin levels, nocturnal melatonin is robustly suppressed by bright light in most individuals (Arendt 2006; Bojkowski et al. 1987; Lewy et al. 1980; McIntyre et al. 1989). Laboratory studies of melatonin suppression by light in humans involve collection of blood, saliva or urine at night, when the hormone typically rises in healthy individuals. Human studies employing the acute melatonin suppression response as a primary dependent variable are generally less labor- and time-intensive than the protocols required for assessment of circadian phase shifting, allowing for more powerful within-subjects experimental designs and increased replication within and between labs.
Melatonin therapy for blunt trauma and strenuous exercise: A mechanism involving cytokines, NFκB, Akt, MAFBX and MURF-1
Published in Journal of Sports Sciences, 2018
Gerald J. Maarman, Russel J. Reiter
Melatonin is an indole amine derivative of the amino acid tryptophan and produced in the pineal gland (Stehle, Reuss, Riemann, Seidel, & Vollrath, 1991). The rhythmic production and secretion of melatonin by the pineal gland regulates the circadian clock and thus melatonin plays a role in timing of sleep, but also nocturnal blood pressure and core body temperature (Dawson & Encel, 1993; Pechanova, Paulis, & Simko, 2014; Reiter, Tan, & Korkmaz, 2009). Melatonin is present in cells and tissues as well as biological fluids such as saliva, breast milk and cerebrospinal fluid (Acuna-Castroviejo et al., 2014; Reiter, Tan, Rosales-Corral, & Manchester, 2013). Melatonin has many functions including antioxidant (Maarman et al., 2016, 2015; Tan, Manchester, Esteban-Zubero, Zhou, & Reiter, 2015; Verma, Hashim, Jayapalan, & Subramanian, 2014) and anti-inflammatory properties (Esposito & Cuzzocrea, 2010; Mauriz, Collado, Veneroso, Reiter, & Gonzalez-Gallego, 2013; Tahan et al., 2011).
A review of the impact of shift work on occupational cancer: Part 2 – mechanistic and health and safety evidence
Published in Policy and Practice in Health and Safety, 2018
J. O. Crawford, J. W. Cherrie, A. Davis, K. Dixon, C. Alexander, H. Cowie, D. M. McElvenny
Melatonin, which is produced in the pineal gland acting via the suprachiasmatic nucleus, varies rhythmically throughout the day, regulating the expression of clock genes and promoting the onset of sleep. Autonomous circadian clocks, also controlled by the suprachiasmatic nucleus, are also present in cells in peripheral tissues (Kelleher, Rao, & Maguire, 2014). Exposure to light during the ‘biological night’ supresses the production of melatonin and it has been hypothesized that this may increase the risk of breast cancer. Animal experiments have fairly consistently shown that melatonin can inhibit the growth of mammary tumours (Blask et al., 2005; Stevens, Brainard, Blask, Lockley, & Motta, 2013; Van Dycke et al., 2015). Blask et al. (2005) was the first to clearly demonstrate in an animal model with human breast cancer xenografts, that increasing intensities of light during each of the normal dark period produced a dose-related suppression of nocturnal melatonin levels in the blood and a stimulation of tumour growth. It was originally argued that in women, lower circulating melatonin levels might cause or be associated with higher oestrogen concentrations, but it is clear that the mode of action would likely have to be more complex and, for example, Langley et al. (2012) found no association between melatonin and sex hormone levels in a population of nurses working rotating shifts.