• Toxicological Research
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• v.15 no.1
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• pp.39-45
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• 1999

To investigate the preventive effects of melatonin (MLT) on the immunotoxicity of cadmium acetate[Cd(AC)2] in ICR mice, Mlt(10,50mg/kg as cadmium) were orally administered to mice once a day (5:00, PM) for 28 consecutive days. Cadmium(Cd) test solution was also administered at 25mg/kg of cadmium through the same route 2hr after administration of MLT daily, Mice were immunized and challenged with sheep red blood cells (SRBC). Immune functions evaluated were delayed type hypersensitivity (DTH) response, mitogenic response, and flow cytometry analysis. The results of these studies were summarized as follows ; DTH response was abnormally increased in mice treated with Cd alone. DTH response was normally depressed in mice treated with Cd plus MLT along with the increase of MLT doses. The mitogenic response of splenic T cell to Con A and that of B cells to LPS was remarkably increased by MLT treatment as compared with treatment of Cd alone In case of CD 8+ cells, the slight increase was observed in MLT treatment. Splenic T cells and B cells were significantly increased by MLT treatment as compared with treatment with Cd alone. These results suggest that MLT has significant preventive effects on the immunotoxic status induced by Cd exposure.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.143-150
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• 1999

melatonin (MLT), N-acetyl-5-methoxytryptamine, is mainly secreted by the pineal gland. The ultraviolet (UV), infrared (IR) and 1H-NMR spectra of irradiated and non-irradiated MLT were measured, and phototoxicity tests of MLT, anthracence (positive control) and sodium lauryl sulfate (SLS, negative control) were performed. The methods employed include both in vitro test such as MTS assay using the human fibroblast cell and yeast growth inhibition assay using Candida albicans and in vivo method using the skin of guinea pig. UV absorption spectra and 1H-NMR spectra of MLT were changed by UVA (365 nm, 15 J/$\textrm{cm}^2$), but IR spectra of MLT were not changed. The fifty percent inhibitory concentration (IC50) ratio (UV-/UV+) of MLT was 10. The inhibition zone of irradiated-paper disks treated with MLT was not observed. According to the results of histophathological examination, no pathologic lesion was observed in the non-irradiated group, but slight degeneration of keratinocytes in the epidermis, homorrhage and vasodilation in dermis were observed in the irradiated group. These results indicated that the molecular structure of MLT is altered by UVA to unidentified photoproducts and a moderate phototoxicity of MLT is predicted.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.1
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• pp.37-43
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• 2012

We have investigated the effect of melatonin (MLT) on specific growth rate (SGR% $day^{-1}$), condition factor (k), gonado-somatic-index (GSI), histological structures of gonads, serum as well as gonadal protein and lipid in Nile tilapia Oreochromis niloticus. MLT treatment in the dose of 25 ${\mu}g/L$ for three weeks reduced SGR% $day^{-1}$ ($0.9{\pm}0.04$) as compared to control ($1.23{\pm}0.026$). The GSI value was significantly (p<0.05) reduced to $1.77{\pm}0.253$ from control where it was $2.56{\pm}0.25$. Serum protein level increased from $9.33{\pm}2.90$ mg/ml (control) to $11.67{\pm}1.45$ mg/ml after MLT treatment while there was depressed serum triglycerides ($86.16{\pm}1.078$ mg/dl) and cholesterol ($126.66{\pm}0.88$ mg/dl) as compared to control values where these were $123.0{\pm}1.23$ mg/dl and $132.0{\pm}1.65$ mg/dl respectively. Histological structure of ovary showed small eggs of early perinucleolus stage after MLT treatment while testicular structure of control and MLT treated fish was more or less similar. It is concluded that exogenous melatonin suppressed SGR% $day^{-1}$, GSI, ovarian cellular activity, protein and lipid biosynthesis, in tilapia suggesting that melatonin is useful in manipulating the gonadal maturity in fishes.

• Journal of Korean Neurosurgical Society
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• v.57 no.3
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• pp.147-151
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• 2015

Objective : Neuroblastoma is one of common childhood tumors. Although its mortality is very high, there is no effective treatment yet. The aim of this project is to evaluate cytotoxic effects of melatonin (MLT) an endogen hormone and 13-cis retinoic acid (13-cis-RA) also named as isotretinoin an analogue of vitamin A on neuroblastoma SH-SY5Y cell line. Methods : In this study, SH-SY5Y cell line was used. After cell culture, the cells were exposed to different doses of MLT and 13-cis-RA. 24 and 48 hours later. While the viabilities was estimated with MTT cell viability assay test, apoptotic indexes were calculated after staining with TUNEL based apoptosis kit. Results : It was observed that MLT has very effective cytotoxic potential than 13-cis-RA on neuroblastoma cell line. At the same time, when MLT and 13-cis-RA were combined, this effect was potentiated. On the other hand, it was found that the effect of 13-cis-RA individually on neuroblastoma cells was very slight. Conclusion : We suggest that in the treatment of patient with neuroblastoma, MLT is very effective and also this effect can be augmented by combination with 13-cis-RA.

• Journal of Veterinary Clinics
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• v.18 no.4
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• pp.374-379
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• 2001

These studies were performed to investigate the effect of antioxidants, melatonin (MLT) and ascorbic acid (AA), on the diabetic complications. In the experiment, twenty-four Sprague Dawley rats were divided into four groups; Group 1: no treatment (control) (n=6), Group 2: Streptozotocin (STZ; 65 mg/kg b.w. ip) treatment (n=6), Group 3: MLT (10 mg/kg b.w. ip) treatment (n=6), Group 4: ascorbic acid (AA: 40 mg/kg b.w.ip) treatment (n=6). Rats were sacrificed and collected designated samples (blood, kidney, pancreas) at the 21 days after antioxidant treatment (the 8th week after STZ injection). There was no significant change of body weight during the experiment period in the all groups. The concentration of blood glucose was decreased below 200 mg/dl in MLT. The concentration of HbA$_1$c level was decreased significantly in MLT (7.3$\pm$0.66%) compared with STZ (15.1$\pm$1.58%) (p<0.01). No significant change of SOD activity in the RBC and kidney was found in the all groups. In the pancreas, MLT (1.42$\pm$0.17 U/ml) and AA(1.65$\pm$0.16 U/ml) decreased SOD activity compared with STZ (4.10$\pm$0.27 U/ml). However, there was no significant difference among MLT and AA. The level of malondialdehyde(MDA) as an indicator of lipid peroxydation was decreased in MLT compared with STZ in the plasma, kidney and pancreas(p<0.01). These findings suggest that melatonin could prevent the complications of diabetes mellitus.