Metabolic Effects of Prolonged Melatonin Administration and Short-Term Fasting in Laboratory Rats

Bojková, Bianka; Marková, Martina; Ahlersová, E; Ahlers, I; Adámeková, E.; Kubatka, Peter; Kassayová, Monika

doi:10.2754/avb200675010021

Cited by 22 publications

(17 citation statements)

References 45 publications

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“…For exam ple, an increase in the incidence of pancreatic diabetes incidence was observed in the hereditary hypertrophy of the PG. According to several authors, this was mediated by an increase in the tolerance to glucose and a decrease in insulin synthesis [28].…”

Section: Functional Changes In the Pg With Agingmentioning

confidence: 99%

Morphofunctional and molecular bases of pineal gland aging

Khavinson

Linkova

2012

Hum Physiol

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Together with the hypophysis and hypothalamus, the epiphysis (pineal gland, PG) is one of the highest centers of the endocrine system of the body [1]. The aging rate of the neuroimmunoendocrine system and age related pathology development are connected with involution of the PG, which, in turn, is determined to a greater degree by a decrease in its functional activity and to a lesser degree, by morphological and molecular changes [2,3]. Morphological Changes in the PG with AgingThe study of autopsy samples of the PGs obtained from 2700 subjects aged from several months to 90 years can be used as the initial point for the analysis of pub lished data on age related changes in the PG. It was shown that PG weight increases from 80-100 to 150 160 mg in the age interval 10-50 years [4]. PG weight is inversely proportional to sexual activity; therefore, this index is higher in pubertal and post menopausal peri ods than in the period of sexual maturity. The increase in the gland weight during aging was related to an increase in the volume of fibrous tissue and the number of cysts without a significant decrease in the number of pinealocytes in an organ's parenchyma. Changes in the connective tissue composition have been observed: the number of collagen fibers is increased, and the number of argyrophilic fibers is decreased [5].According to the computed tomography data, the volume of the PG characterizing its functional activity decreased at the age interval from 21 to 60 and then sta bilized [6]. These data are in good correlation with the study [7], which shows that there are no pronounced differences in PG structures at a young and elderly age.Sequential changes in three prevaling types of PG structure (cellular, trabecular, and alveolar) occur [8].The cellular type of structure of the PG is typical of a young age. PG is represented by a continuous field of pinealocytes.The trabecular type of the PG, glandular tissue with differently directed stromal septum, is typical of mid dle aged subjects. Replacement of the trabecular type by the alveolar type of PG structure is typical of elderly subjects. Trabeculae subdivide PG in alveolar structure into circular or polygonal lobules separated by stromal rings.In addition, one can see age related changes in the vessels of the PG. After birth, PG vessels are located among pinealocytes. Expansion of argyrophilic stroma around the vessels that takes place with age is the reason of the transition from a cellular to trabecular type of structure of the PG. A dense network of vessels enlaces the parenchymal lobules of the PG determining its alve olar structure. In subjects over 60 years of age, one can see the appearance of outgrowths of the reticular frame of connective tissue in the development of sclerosing processes in the PG. The blood circulation in the PG is decreased as compared to subjects aged 40-45 years. Age related decrease in trophism in the PG results in involution changes in its cells, pinealocytes.Accumulation of lipofuscin and lipid inclusions, as well as fragmentati...

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Section: Functional Changes In the Pg With Agingmentioning

confidence: 99%

Morphofunctional and molecular bases of pineal gland aging

Khavinson

Linkova

2012

Hum Physiol

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“…In addition, recent studies have shown that melatonin influences carbohydrates and lipid metabolism in goldfish liver and muscle 17 ; inconsistent results, instead, were found in mammals. [21][22][23] In this regard, among signals that regulate feeding behavior and metabolism, leptin (LPT) plays a key role as a satiety molecule controlling body weight maintenance. In both mammals and fish, LPT is secreted by a variety of tissues such as adipocytes, stomach, muscle, placenta, and brain, [24][25][26][27] and its anorexigenic action is exerted by stimulating melanocyte-stimulating hormone and subsequently MC4R, the key receptor in appetite regulation of the melanocortin system.…”

Section: Introductionmentioning

confidence: 99%

Melatonin and Peripheral Circuitries: Insights on Appetite and Metabolism in Danio Rerio

et al. 2013

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Melatonin is a neuroendocrine transducer of circadian/circannual rhythms able to synchronize organism's physiological activity. On the basis of our recent findings on appetite regulation by melatonin in the zebrafish brain, the aim of this study was to evaluate melatonin's role in peripheral circuitries regulating food intake, growth, and lipid metabolism. For this purpose, the effect of two melatonin doses (100 nM and 1 lM) administered for 10 days, via water, to adult zebrafish was evaluated at both physiological and molecular levels. The major signals controlling energy homeostasis were analyzed together. Additionally, the effect of melatonin doses on muscle metabolic resources was evaluated. The results obtained indicate that melatonin reduces food intake by stimulating molecules involved in appetite inhibition, such as leptin (LPT), in the liver and intestine and MC4R, a melanocortin system receptor, in the liver. Moreover, melatonin decreases hepatic insulin-like growth factor-I (IGF-I) gene expression, involved in growth process and other signals involved in lipid metabolism such as proliferator-activated receptors (PPARa, b, and c) and sterol regulatory element-binding protein (SREBP). These results were correlated with lower levels of lipids in the muscles as evidenced by the macromolecular pools analyses. The findings obtained in this study could be of great interest for a better understanding of the molecular mechanisms as the basis of food intake control and, in turn, can be a useful tool for medical and aquaculture applications.

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“…Studies focused on the relationship between melatonin and carbohydrate and lipid metabolism in mammals have provided inconsistent results. Particularly, the effects on the glucose metabolism and the underlying mechanisms remain to be elucidated [9, 17]. Hypoglycemia, hyperglycemia [9] and no effect [10, 25] after melatonin administration have been reported in rats.…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, the effects on the glucose metabolism and the underlying mechanisms remain to be elucidated [9, 17]. Hypoglycemia, hyperglycemia [9] and no effect [10, 25] after melatonin administration have been reported in rats. The effect of melatonin on lipid metabolism can also vary depending on the experimental conditions, and both reductions [25, 26] and increases [9] in liver and plasma lipids have been reported.…”

Section: Introductionmentioning

confidence: 99%

Melatonin reduces body weight in goldfish (Carassius auratus): effects on metabolic resources and some feeding regulators

Pedro

Martínez‐Álvarez

Delgado

2008

Journal of Pineal Research

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The objective of the present study was to analyze the effects of chronic melatonin (10 microg/g body weight) on body weight and the main energetic reserves, particularly hepatic and muscle content of proteins, lipids and glycogen in goldfish. In addition, we studied plasma leptin and ghrelin, and hypothalamic content of neuropeptide Y (NPY) and monoamines after chronic melatonin treatment in order to elucidate a possible interplay between melatonin and these feeding regulators on the body weight regulation in this species. Body weight gain and specific growth rate were reduced (74% and 76%, respectively) after chronic (10 days) intraperitoneal (i.p.) treatment with melatonin. The carbohydrate and lipid metabolism was regulated by melatonin in goldfish, because this indoleamine reduced muscle glycogen stores and increased lipid mobilization. A suppressive trend, but not statistically significant, in circulating ghrelin was observed after chronic treatment with melatonin. Chronic melatonin administration significantly reduced noradrenergic metabolism and increased dihydroxiphenylacetic acid content in the hypothalamus, without significant modifications in the serotoninergic system. Thus, it could be suggested that melatonin may mediate its action on energy balance in fish, at least in part, via interactions with hypothalamic catecholaminergic system. Plasma leptin and hypothalamic NPY remained unaltered after melatonin treatment, suggesting that these feeding regulators may not be involved in the effects of melatonin on energy homeostasis in fish.

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Metabolic Effects of Prolonged Melatonin Administration and Short-Term Fasting in Laboratory Rats

Cited by 22 publications

References 45 publications

Morphofunctional and molecular bases of pineal gland aging

Morphofunctional and molecular bases of pineal gland aging

Melatonin and Peripheral Circuitries: Insights on Appetite and Metabolism in Danio Rerio

Melatonin reduces body weight in goldfish (Carassius auratus): effects on metabolic resources and some feeding regulators

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