TCDD Decreases Rapidly and Persistently Serum Melatonin Concentration Without Morphologically Affecting the Pineal Gland in TCDD-Resistant Han/Wistar Rats

1991 ◽  
Vol 69 (6) ◽  
pp. 427-432 ◽  
Author(s):  
Jere Linden ◽  
Raimo Pohjanvirta ◽  
Timo Rahko ◽  
Jouko Tuomisto
2006 ◽  
Vol 97 (5) ◽  
pp. 1279-1287 ◽  
Author(s):  
Alexies Dagnino-Subiabre ◽  
Juan A. Orellana ◽  
Carlos Carmona-Fontaine ◽  
Juan Montiel ◽  
Gabriela Diaz-Veliz ◽  
...  

2007 ◽  
pp. 79-88
Author(s):  
N Vázquez ◽  
E Díaz ◽  
C Fernández ◽  
V Jiménez ◽  
A Esquifino ◽  
...  

The laboratory rat, a non-photoperiodic rodent, exhibits seasonal fluctuations of melatonin. Melatonin has been found to be readily transferred from the maternal to the fetal circulation. No data exist on the possible influence of maternal pineal gland upon seasonal variations of the offspring. The aim of the present study was to asses the influence of the maternal melatonin rhythm on the offspring postnatal development of the reproductive hormones LH, FSH and prolactin. Male offspring from control, pinealectomized (PIN-X) and PIN-X + melatonin (PIN-X+MEL) mother Wistar rats were studied at 21, 31, and 60 days of age. Seasonal age-dependent variations were found for all hormones studied in control offspring but PIN-X offspring showed a tendency to have reduced duration or altered seasonal variations. Maternal melatonin treatment to PIN-X mothers partially restored the effect of pinealectomy. The chronological study of LH, FSH, and prolactin in PIN-X offspring also showed an altered pattern as compared to control-offspring. Melatonin treatment to the mothers partially restored the developmental pattern of reproductive hormones. Results of this study indicate that maternal pineal gland of the laboratory rat is involved in the seasonal postnatal development variations of reproductive hormones of the offspring.


2015 ◽  
Vol 43 (6) ◽  
pp. 838-843 ◽  
Author(s):  
Silke Treumann ◽  
Roland Buesen ◽  
Sibylle Gröters ◽  
Jens-Olaf Eichler ◽  
Bennard van Ravenzwaay

1980 ◽  
Vol 20 (4A) ◽  
pp. 1051-1060 ◽  
Author(s):  
M. G. M. BALEMANS ◽  
J. Van BENTHEM ◽  
W. C. LEGERSTEE ◽  
A. de MOREE ◽  
H. J. P. M. NOTEBORN ◽  
...  

2006 ◽  
Vol 75 (2) ◽  
pp. 161-167
Author(s):  
K. Stebelová ◽  
M. Mach ◽  
I. Herichová ◽  
E. Ujházy ◽  
M. Zeman

Melatonin (MEL) is involved in regulation of variety of physiological processes. Beside the pineal gland, the presence of MEL was confirmed in the gastrointestinal tract (GIT), where it may exert multiple actions. We investigated the effects of a single MEL administration of 0.4, 4.0 and 40.0 μg MEL/ml of tap water on MEL levels in rat plasma, pineal gland and duodenum. In addition, we studied the effect of a prolonged administration of MEL, an anticonvulsant drug phenytoin (PHT) and a combination of MEL+PHT, on MEL concentrations in pregnant rats and their fetuses. Single MEL administration of 4.0 and 40.0 μg MEL/ml resulted in a dose-related increase of MEL concentration in the rat plasma and duodenum but in a decrease of MEL in the pineal gland. After a prolonged MEL administration, MEL levels in duodenal tissues were significantly lower in control group and group treated with PHT as compared to animals, where MEL and PHT were administered simultaneously. A significant increase in MEL concentration was recorded in the intestine of fetuses taken from mothers treated with MEL and MEL + PHT. Our results indicate a dose-related absorption of MEL from tap water to GIT tissues of pregnant rats and their fetuses, where MEL may increase the protection of the intestinal mucose.


2022 ◽  
Author(s):  
Shayan Balkhi ◽  
Marie Saghaeian Jazi ◽  
Nader Mansour Samaei ◽  
Mahtab Farahmandrad

Abstract According to the World Health Organization, glioblastoma, also known as the fourth grade in the development of astrocytoma, is a glial tumor limited to the central nervous system with a strong ability to invade the brain parenchyma. Melatonin can be generated outside of the pineal gland tissue, according to new research. Melatonin is produced by mitochondria independently but in concert with cell demands, and it plays an important function in cell cycle and metabolism regulation. As a result, we set out to investigate the association between cell metabolism and the serum shock-induced increase in endogenous melatonin, as well as the percentage of cell proliferation.Background: Melatonin can be produced in the mitochondria organelle of glioblastoma cells without the involvement of the pineal gland, according to new research. Regarding the physiological function of melatonin secreted by the pineal gland in the regulation of rhythmicity, the goal of this study was to see if the glioblastoma cell's melatonin production ability could be influenced using a typical serum shock technique established for cellular rhythm regulator.Material and methods: First, U87-MG glioblastoma cells were cultured in a DMEM medium containing 10% FBS and then cells were treated with a standard serum shock process (no FBS, 8h). The concentration of melatonin was measured using ELISA method in supernatant and cell extracts of Shock and control groups. The cell proliferation was measured by using BrdU staining and flow cytometry assessment. The gene expression levels of some mitochondria or circadian related genes including TFAM, BMAL1, PPARGC1A(PGC1-α), and DNM1L(DRP1) were measured, using qRT-PCR method.Results: In comparison to the control group, serum shock treated U87-MG glioblastoma cells had higher concentrations of cellular and released endogenous melatonin (two times). At the mRNA level, we discovered considerable upregulation of mitochondrial or circadian regulator genes (TFAM, BMAL1, PPARGC1A, and DNM1L); in the shock group compared to the control group (P <0.0002). Furthermore, although the percentage of proliferative cells (Brdu positive) was higher in the shock group, it was not statistically significant.Conclusion: The serum shock procedure has a significant impact on the U87-MG cell line's cellular activity. In terms of the study's findings, it's worth noting that an increase in endogenous melatonin concentration influences several signaling pathways within the U87-MG cell line, as seen by the increased expression of candidate genes.In light of the findings of this study, it's worth noting that further research into the role of endogenous melatonin and its effects on cancer cells is critical, and that comparing the results of normal and cancer cells can reveal the hotspots of the signaling pathways involved, which could facilitate in better understanding the biology of glioblastoma.


Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2483-2493 ◽  
Author(s):  
Andreas Gunter Bach ◽  
Eckhard Mühlbauer ◽  
Elmar Peschke

A decrease in the nighttime release of the pineal hormone melatonin is associated with aging and chronic diseases in animals an humans. Melatonin has a protective role in type 2 diabetes; however, its synthesis itself is affected in the disease. The aim of this study was to detect crucially impaired steps in the pineal melatonin synthesis of type 2 diabetic Goto-Kakizaki (GK) rats. Therefore, plasma melatonin concentrations and the pineal content of melatonin and its precursors (tryptophan, 5-hydroxytryptophan, serotonin, and N-acetylserotonin) were quantified in GK rats compared with Wistar rats (each group 8 and 50 wk old) in a diurnal manner (four animals per group and per time point). Additionally, the expression of pineal adrenoceptor subtype mRNA was investigated. We found that in diabetic GK rats, 1) inhibitory α-2-adrenoceptors are significantly more strongly expressed than in Wistar rats, 2) the formation of 5-hydroxytryptophan is crucially impaired, and 3) the pineal gland protein content is significantly reduced compared with that in Wistar rats. This is the first time that melatonin synthesis is examined in a type 2 diabetic rat model in a diurnal manner. The present data unveil several reasons for a reduced melatonin secretion in diabetic animals and present an important link in the interaction between melatonin and insulin.


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