Швидкість всмоктування глюкози в тонкій кишці щурів на тлі надлишку та нестачі мелатоніну

Abstract

У наш час стоїть питання про необхідність усунення, або зменшення ефектів негативного впливу гіпомелатонінемії при тривалому перебуванні організму в умовах цілодобового освітлення у великих містах і при деяких видах професійної діяльності. У зв’язку з цим, необхідні всебічні дослідження впливу надлишку і нестачі мелатоніну на організм. У даній статті показані результати вивчення впливу надлишку і нестачі мелатоніну на швидкість всмоктування глюкози в тонкій кишці щурів. Надлишок мелатоніну стимулює всмоктування глюкози в тонкій кишці на 10%, а його нестача – навпаки гальмує на 18%. Проведені дослідження виявили, що при гіпермелатонінемії швидкість всмоктування виявилася на 26% більше, ніж при гіпомелатонінемії, що вказує на контрінсулярні властивості мелатоніну.

В наше время стоит вопрос о необходимости устранения, или уменьшения эффектов негативного влияния гипомелатонинемии при длительном пребывании организма в условиях круглосуточного освещения в больших городах и при некоторых видах профессиональной деятельности. В связи с этим, необходимы всесторонние исследования влияния избытка и нехватки мелатонина на организм. В данной статье показанные результаты изучения влияния избытка и нехватки мелатонина на скорость всасывания глюкозы в тонкой кишке крыс. Избыток мелатонина стимулирует всасывание глюкозы в тонкой кишке на 10%, а его недостаток – наоборот тормозит на 18%. Проведенные исследования выявили, что при гипермелатонинемии скорость всасывания оказалась на 26% больше, чем при гипомелатонинемии, что указывает на контринсулярные свойства мелатонина.

Melatonin is a somnogenic neurotransmitter, a hormone, an antioxidant that blocks the proliferation and synthesis and secretion of gonadotropins. It is known that melatonin is a universal endogenous adaptogen, has antioxidant, immunomodulatory properties, and reducing its products in case of violations of the light regime is accompanied by signs of accelerated aging and an increased risk of tumors. In adults, about 30 μg melatonin is synthesized per day, its concentration in blood serum at night is 30 times higher than in the daytime, with peak activity at 2:00 pm, its production is suppressed by the reception of light information by the mesh of the eye. Melatonin is synthesized in the epiphysis only when the light doesn`t influence on the eyes. The melatonin APUD-system acts as apocryphal and paracrine. The presence of melatonin is also determined in all sections of the gastrointestinal tract (GIT) of animals and humans, from the esophagus to the rectum, with a maximum in the mucous layer and less in the submucosal and muscular layers. The presence of melatonin in the organs of the gastrointestinal tract was demonstrated in studies in pineallectomized animals. This indicates the synthesis of melatonin by the organs of the gastrointestinal tract. Based on these studies it is possible to assume that melatonin plays an important role in the physiology of the gastrointestinal tract and disturbance of its secretion may be the cause of various pathologies of the gastrointestinal tract. The problem of the effect of melatonin on the gastrointestinal tract is relevant, since the relationship between the degree of disturbance in the rhythm of melatonin production and the clinical course of some diseases (ulceration of the stomach and duodenum) has been detected, and there isn`t studies on the effect of excess and lack of melatonin on the functioning of the gastrointestinal tract. In addition, there is a large group of people working in the night shift, exists in the conditions of round the clock lighting (large cities, polar day, sleep in light), which blocks the synthesis and secretion of melatonin by the epiphysis. There is also the possibility of uncontrolled use of melatonin as sleeping pills. All this indicates to the nesessity for a more detailed study of melatonin on the physiological processes in the body. Therefore, the purpose of the work was to study the effect of excess and lack of melatonin on the rate of glucose`s absorption in the small intestine of rats. The studies were performed on 24 sexually mature white male rats of the Wistar line weighing 220-260 g (3 groups of 8 animals). The first group was an intact, held in light mode: 12 hours of darkness – 12 hours of light for a period of 30 days. In the second group for modeling hypomelatoninemia animals were kept in the regime of constant illumination (1000-1500 lux) for 30 days. In the third group, hypermelatoninemia was modeled by the administration of melatonin in the diet with a dose of 1 mg/kg body weight/day and 24-hour darkness for 30 days. Determined the amount of glucose that was absorbed in the isolated loop of the small intestine of rats for 10 min. The study found that an excess of melatonin stimulates the absorption of glucose in the small intestine by 10%, and its lack of – on the contrary, inhibits by 18%. With hypermelatoninemia, the rate of absorption was 26% higher than with gipomelatoninemia, which indicates the contrainsular properties of melatonin.