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Ige AO, Adekanye OS, Adewoye EO. Intermittent exposure to green and white light-at-night activates hepatic glycogenolytic and gluconeogenetic activities in male Wistar rats. J Basic Clin Physiol Pharmacol 2021:jbcpp-2020-0251. [PMID: 34147042 DOI: 10.1515/jbcpp-2020-0251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 04/15/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Exposure to light-at-night (LAN) has been reported to impair blood glucose regulation. The liver modulates blood glucose through mechanisms influenced by several factors that include peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α) and glucose-6-phosphatase (G6Pase). This study investigated the effect of intermittent exposure to green and white LAN on some hepatic glucose regulatory factors in male Wistar rats. METHODS Animals were divided into three equal groups. Group I (control) was exposed to normal housing conditions. Groups II and III were each daily exposed to either green or white LAN for 2 h (7-9 pm) for 14 days. Body weight and blood glucose was monitored on days 0, 7, and 14. Thereafter, retro-orbital sinus blood was obtained after light thiopental anaesthesia and serum insulin was determined. Liver samples were also obtained and evaluated for glycogen, PGC-1α, and G6Pase activity. Insulin resistance was estimated using the HOMA-IR equation. RESULTS Body weight and blood glucose on days 7 and 14 increased in groups II and III compared to control. Hepatic PGC-1α and G6Pase increased in group II (2.33 ± 0.31; 2.07 ± 0.22) and III (2.31 ± 0.20; 0.98 ± 0.23) compared to control (1.73 ± 0.21; 0.47 ± 0.11). Hepatic glycogen was 71.8 and 82.4% reduced in groups II and III compared to control. Insulin in group II increased (63.6%) whiles group III values reduced (27.3%) compared to control. Insulin resistance increased in group II (0.29 ± 0.09) compared to control (0.12 ± 0.03) and group III (0.11 ± 0.03), respectively. CONCLUSIONS Exposure to 2 h green and white LAN in the early dark phase increases hepatic glycogenolysis and gluconeogenetic activities resulting in increased blood glucose. In male Wistar rats, exposure to green but not white LAN may predispose to insulin resistance.
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Affiliation(s)
- Abayomi O Ige
- Applied and Environmental Physiology Unit, Department of Physiology, University of Ibadan, Ibadan, Nigeria
| | - Olubori S Adekanye
- Applied and Environmental Physiology Unit, Department of Physiology, University of Ibadan, Ibadan, Nigeria
| | - Elsie O Adewoye
- Applied and Environmental Physiology Unit, Department of Physiology, University of Ibadan, Ibadan, Nigeria
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Abstract
Exposing chicks to one hour of light during the night disrupts the release of a hormone that is needed by cells in the developing brain to survive.
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Affiliation(s)
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Canada
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Haraguchi S, Kamata M, Tokita T, Tashiro KI, Sato M, Nozaki M, Okamoto-Katsuyama M, Shimizu I, Han G, Chowdhury VS, Lei XF, Miyazaki T, Kim-Kaneyama JR, Nakamachi T, Matsuda K, Ohtaki H, Tokumoto T, Tachibana T, Miyazaki A, Tsutsui K. Light-at-night exposure affects brain development through pineal allopregnanolone-dependent mechanisms. eLife 2019; 8:45306. [PMID: 31566568 PMCID: PMC6850767 DOI: 10.7554/elife.45306] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 09/29/2019] [Indexed: 12/27/2022] Open
Abstract
The molecular mechanisms by which environmental light conditions affect cerebellar development are incompletely understood. We showed that circadian disruption by light-at-night induced Purkinje cell death through pineal allopregnanolone (ALLO) activity during early life in chicks. Light-at-night caused the loss of diurnal variation of pineal ALLO synthesis during early life and led to cerebellar Purkinje cell death, which was suppressed by a daily injection of ALLO. The loss of diurnal variation of pineal ALLO synthesis induced not only reduction in pituitary adenylate cyclase-activating polypeptide (PACAP), a neuroprotective hormone, but also transcriptional repression of the cerebellar Adcyap1 gene that produces PACAP, with subsequent Purkinje cell death. Taken together, pineal ALLO mediated the effect of light on early cerebellar development in chicks.
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Affiliation(s)
- Shogo Haraguchi
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan.,Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Masaki Kamata
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
| | - Takuma Tokita
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
| | - Kei-Ichiro Tashiro
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
| | - Miku Sato
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
| | - Mitsuki Nozaki
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
| | - Mayumi Okamoto-Katsuyama
- Department of Applied Chemistry, School of Science and Engineering, Waseda University, Tokyo, Japan
| | - Isao Shimizu
- Department of Applied Chemistry, School of Science and Engineering, Waseda University, Tokyo, Japan
| | - Guofeng Han
- Laboratory of Stress Physiology and Metabolism, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka, Japan
| | - Vishwajit Sur Chowdhury
- Laboratory of Stress Physiology and Metabolism, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka, Japan
| | - Xiao-Feng Lei
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Takuro Miyazaki
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Joo-Ri Kim-Kaneyama
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Tomoya Nakamachi
- Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan
| | - Kouhei Matsuda
- Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan
| | - Hirokazu Ohtaki
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Toshinobu Tokumoto
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Tetsuya Tachibana
- Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, Japan
| | - Akira Miyazaki
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo, Japan
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González-González A, Mediavilla MD, Sánchez-Barceló EJ. Melatonin: A Molecule for Reducing Breast Cancer Risk. Molecules 2018; 23:E336. [PMID: 29415446 PMCID: PMC6017232 DOI: 10.3390/molecules23020336] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 01/10/2023] Open
Abstract
The objective of this article is to review the basis supporting the usefulness of melatonin as an adjuvant therapy for breast cancer (BC) prevention in several groups of individuals at high risk for this disease. Melatonin, as a result of its antiestrogenic and antioxidant properties, as well as its ability to improve the efficacy and reduce the side effects of conventional antiestrogens, could safely be associated with the antiestrogenic drugs presently in use. In individuals at risk of BC due to night shift work, the light-induced inhibition of melatonin secretion, with the consequent loss of its antiestrogenic effects, would be countered by administering this neurohormone. BC risk from exposure to metalloestrogens, such as cadmium, could be treated with melatonin supplements to individuals at risk of BC due to exposure to this xenoestrogen. The BC risk related to obesity may be reduced by melatonin which decrease body fat mass, inhibits the enhanced aromatase expression in obese women, increases adiponectin secretion, counteracts the oncogenic effects of elevated concentrations of leptin; and decreases blood glucose levels and insulin resistance. Despite compelling experimental evidence of melatonin's oncostatic actions being susceptible to lowering BC risk, there is still a paucity of clinical trials focused on this subject.
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Affiliation(s)
- Alicia González-González
- Department of Physiology and Pharmacology, School of Medicina, University of Cantabria, 39011 Santander, Spain.
| | - María Dolores Mediavilla
- Department of Physiology and Pharmacology, School of Medicina, University of Cantabria, 39011 Santander, Spain.
| | - Emilio J Sánchez-Barceló
- Department of Physiology and Pharmacology, School of Medicina, University of Cantabria, 39011 Santander, Spain.
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Abstract
Decreased melatonin production, due to nighttime exposure to light, has been proposed as one of the physiological mechanisms increasing cancer risk in night workers. However, few studies measured melatonin production in night workers, and most of these studies did not measure melatonin over 24 h. One study compared total melatonin production between day and night shifts in rotating night workers and did not find significant differences. However, without baseline measures, it was not possible to exclude that melatonin production was reduced during both day and night work. Here, we used data collected in a simulation study of night work to determine the effect of night work on both nighttime and 24-h melatonin production, during three consecutive days of simulated night work. Thirty-eight healthy subjects (15 men, 23 women; 26.6 ± 4.2 years) participated in a 6-d laboratory study. Circadian phase assessments were made with salivary dim light melatonin onset (DLMO) on the first and last days. Simulated day work (09:00-17:00 h) occurred on the second day, followed by three consecutive days of simulated night work (00:00-08:00 h). Light intensity at eye level was set at 50 lux during both simulated day and night work. The subjects were divided into three matched groups exposed to specific daytime light profiles that produced various degrees of circadian phase delays and phase advances. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s). For the entire protocol, urine was collected every 2 h, except for the sleep episodes when the interval was 8 h. The aMT6s concentration in each sample was multiplied by the urine volume and then added to obtain total aMT6s excretion during nighttime (00:00-08:00 h) and during each 24-h day (00:00-00:00 h). The results showed that melatonin production progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. This decrease was larger in women using oral contraceptives. There was no difference between the three groups, and the magnitude of the decrease in melatonin production for nighttime and for the 24 h was not associated with the magnitude of the absolute circadian phase shift. As light intensity was relatively low and because the decrease in melatonin production was progressive, direct suppression by nighttime light exposure was probably not a significant factor. However, according to previous experimental observations, the decrease in melatonin production most likely reflects the circadian disruption associated with the process of re-entrainment. It remains to be determined whether reduced melatonin production can be harmful by itself, but long-term and repeated circadian disruption most probably is.
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Affiliation(s)
- Marie Dumont
- Chronobiology Laboratory, Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal , Montreal, Quebec , Canada and
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Abstract
Artificial light decreases the amplitude of daily rhythms in human lifestyle principally by permitting activity and food intake to occur during hours of darkness, and allowing day-time activity to occur in dim light, indoors. Endogenous circadian timing mechanisms that oscillate with a period of 24 h have evolved to ensure physiology is synchronized with the daily variations in light, food, and social cues of the environment. Artificial light affects the synchronization between these oscillators, and metabolic disruption may be one consequence of this. By dampening the amplitude of environmental timing cues and disrupting circadian rhythmicity, artificial lighting might initiate metabolic disruption and contribute to the association between global urbanization and obesity. The aim of this review is to explore the historical, physiological, and epidemiological relationships between artificial light and circadian and metabolic dysfunction.
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Affiliation(s)
- Cathy A Wyse
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G61 1QH , UK
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Vinogradova IA, Anisimov VN, Bukalev AV, Semenchenko AV, Zabezhinski MA. Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats. Aging (Albany NY) 2009; 1:855-65. [PMID: 20157558 PMCID: PMC2816394 DOI: 10.18632/aging.100092] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 09/30/2009] [Indexed: 01/31/2023]
Abstract
We evaluated
the effect of various light/dark regimens on the survival, life span and
tumorigenesis in rats. Two hundred eight male and 203 females LIO rats
were subdivided into 4 groups and kept at various light/dark regimens:
standard 12:12 light/dark (LD); natural lighting of the North-West of Russia (NL); constant light (LL), and constant darkness (DD) since the age of 25 days until
natural death. We found that exposure to NL and LL regimens accelerated
development of metabolic syndrome and spontaneous tumorigenesis, shortened
life span both in male and females rats as compared to the standard LD
regimen. We conclude that circadian disruption induced by light-at-night
accelerates aging and promotes tumorigenesis in rats. This observation
supports the conclusion of the International Agency Research on Cancer that
shift-work that involves circadian disruption is probably carcinogenic to
humans.
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