ISSN 2415-3060 (print), ISSN 2522-4972 (online)
  • 9 of 50
JMBS 2021, 6(1): 65–71
Clinical Medicine

Effects of Prolonged Light Exposure on the Concentration of Some Hormones, Mineral Metabolic Exchange and Immunity Parameters in Students

Gorbach T. V., Balak O. K., Martynova S. N., Vlasenko O. V.

In this work, we studied the influence of artificially prolonged daylight on the concentration of some hormones, the state of mineral metabolism, and immunity in students. Material and methods. The study involved 50 second-year students (44 girls and 6 boys) of Kharkiv National Medical University with different chronotypes. All students were on a proper diet, did not play sports, did not have any chronic diseases, and were healthy during the study period. Students were divided into 2 groups: 1) waking period from 5:00 to 23:00 (25 people), 2) waking period from 8:00 to 3:00 (25 people). Saliva was collected after careful oral hygiene at 8 a.m., 12 a.m., 4 p.m., and 12 p.m. Results and discussion. Our study showed that the artificial prolongation of daylight reduces the concentration of melatonin, especially at night (at the peak of secretion). It is established that at the artificial prolongation of the light day there is an inversion of a rhythm of thyroid's hormones secretion, decrease in their maximum concentration which probably is connected with the adaptation of an organism to an active mental activity at night. The obtained results showed that in students with the evening chronotype, the concentration of cortisol reduced both during the day and at 24 hours, which was probably associated with a decrease in melatonin secretion and its regulatory effect on the adrenal glands. Decreased concentrations of melatonin, cortisol, and thyroid hormones led to the impaired functional activity of the immune system, as evidenced by a decrease in secretory immunoglobulin and lysozyme in the saliva of students with evening chronotype, compared with students with morning chronotype of activity. Changing circadian rhythms of thyroid hormone secretion, reducing their concentration and cortisol content led to the development of metabolic disorders. We noted that dysfunction of mineral metabolism in students with evening chronotype caused a decrease in the concentration of calcium, magnesium, zinc in the saliva of students. The identified characteristics indicate that prolonged daylight reduced the ability to maintain the daily balance of the studied nutrients, which may be a manifestation of desynchrony. The concentration of immunoglobulin A in the saliva of students in the second group in the morning and the evening was significantly lower than in students of group 1, which indicated an absolute deficiency of immunoglobulin and, accordingly, a decrease in immunity with prolonged daylight. Students of group 2 also had a decrease in the content of lysozyme in saliva, which indicated a decrease in the degree of antibacterial protection. The peculiarities in the content of immunoglobulin A and lysozyme are most likely associated with a decrease in the concentration of melatonin. Conclusion. The artificial prolongation of daylight decreased the melatonin concentration in saliva and cortisol concentration. It also caused an inversion of secretion rhythm of thyroid hormones. The students with evening chronotype had a decrease in immunoglobulin A concentration, decrease in lysozyme in saliva and disturbance in a mineral metabolism

Keywords: melatonin, cortisol, thyroid hormones, TSH, immunoglobulin A, lysozyme, mineral metabolism

Full text: PDF (Ukr) 289K

  1. Mittal S. The metabolic syndrome in clinical practice. Springer. 2008; 260: 235-59.
  2. Gushchin JA, Muzhikyan AA, Selezneva AM, Makarova MN. Integrated morphological assessment of experimental atherosclerotic lesions in the rabbits aortas. Originai’nye statyi. 2017; 1: 50-8.
  3. Khyzhkyn EA, Ylyna TN, Lotosh TA, Ylyukha VA, Vynogradova YA, Anysymov VN. Vlyyanye postoyannogo osveshchenyya na antyoksydantnuyu systemu krys [Effect of constant illumination on the antioxidant system of rats]. Trudy Karelskogo nauchnogo tsentra RAN. 2010; 2: 62-7. [Russian]
  4. Magri F, Locatelli M, Balza, Molla G, Cuzzoni G, Fioravanti M, G et al. Changes in endocrine circadianrhythms as of physiological and pathological brain aging. Chronobiol In. 1997; 14: 385-96.
  5. Schernhammer ES Kroenke CH, Dowsett M, Folkerd E, Hankinson SE. Urinary 6-sulfatoxumelatonin levels and their correlations with lifestyle factors and steroid hormone levels. J Pineal Res. 2006 Mar; 40(2): 116-24.
  6. Cipolla-Neto J, Amaral FG, Afeche SC, Tan DX, Reiter RJ. Melatonin, energy metabolism, and obesity: a review. J Pineal Res. 2014 May; 56(4): 371-81.
  7. Thorpy M. Understanding and diagnosing shift work disorder. Postgrad Med. 2011 Sep; 123(5): 96-105.
  8. Viswanathan AN, Schernhammer ES Circulating melatonin and the risk of breast and endometrial cancer in women. Cancer Lett. 2009; 281(1): 11-7.
  9. Zawilska IB. Skene DI, Arendt J. Phisiology and pharmacology of melatonin in relation tobiological rhythms. Pharmacol Rep. 2009; 61(3): 383-410.
  10. Bondarenko LA, Sotnic NN, Chagovets EM, Sergienko LYu, Cherevko AN. Intensity of In vitro Incorporation of H-Melatonin in the Thiroid Gland of Rabbits with Pineal Gland of Rabbits with Pineal Gland Hypofunction. Bulletin of Experimental Biology and Medicine. 2011; 150(6): 753-5.
  11. Pishak VP. Shyshkopodibne tilo ta biokhimichni osnovy adaptatsiyi [Cone-shaped body and biochemical bases of adaptation]. Chernivtsi: Medakademiya; 2006. 152 s. [Ukrainian]
  12. Skalnyi AV. Khimicheskie elementy v fiziolohiyi i ekolohiyi cheloveka [Chemical elements in human physiology and ecology]. M: Izd dom «Oniks 21 stoletiya», 2004. 216 s. [Russian]
  13. Slepushkyn VD, Pashynskyi VH. Epifiz i adaptatsiya orhanizma [The pineal gland and adaptation of the organism]. T: Izd-vo Tomskoho universyteta; 2000. 210 s. [Russian]
  14. Kronenberh HM, Metmed Sh, Polonsky KSh, Larsen PR. Neyroendokrinolohiya [Neuroendocrinology]. Seriya "Endokrynolohiya po Vilyamsu Per s angl.Ed by II Dedov, HM Melnichenko. M: TOV "Rid Elsiver"; 2010. 472 s. [Russian]
  15. Bondarenko AA, Hubina-Vakulyk HI, Hevorkyan AR. Pinealna zaloza i hipotalamo-tyreoidna systema: vikovi ta khronobiolohichni aspekty [Pineal gland and hypothalamic-thyroid system: age and chronobiological aspects]. Kh; 2015. 262 s. [Ukrainian]
  16. Claustrat B, Brun J, Chazot G. The basic physiology and pathophysiology of melatonin Sleep Med Rev. 2005; 9(1):11-24.
  17. Drahovoz SM, Shtryhol SYu, Kalko KO. Farmakokorektsiya desynkhronozu zapalennya [Pharmacocorrection of inflammatory desynchrony]. Materialy naukovo-praktychnoi konferentsyi z mizhnarodnoyu uchastyu "Vikovi ta khronobiolohichni aspekty medytsyny y farmatsiyi", 2018. p. 47-8. [Ukrainian]
  18. Pedersen BK, Febbraio MA. Muscle as an endocrine or-gan: focus on muscle-derived interleukin-6. Physiol Rev. 2008; 88: 1379-406.