• Journal of Microbiology and Biotechnology
• /
• v.12 no.2
• /
• pp.222-227
• /
• 2002

Squalene synthase catalyzes the reductive dimerization of two molecules of farnesyl diphosphate to form squalene at the final branch point of the cholesterol biosynthetic pathway. Due to the unique position of this enzyme in the pathway, its inhibitors may have advantages as antihypercholesterolemic agents. Therefore, selective inhibitors of squalene synthase do not prevent the formation of the essential branch products of the isoprene pathway, such as dolichol, coenzyme-Q, and prenylated proteins, as might be expected for inhibitors of enzymes earlier in the pathway; for example, lovastatin and mevalotin. The current study reports that CJ90002, a pentagalloylglucose isolated from Paeonia moutan SIM (Paeoniaceae), which is an important Chinese crude drug used in many traditional prescriptions, was a potent inhibitor of rat microsomal squalene synthase, and also a potent inhibitor of cholesterol biosynthesis in vitro. In addition, the intraperitoneal and oral administration of CJ90002 had a significant lowering effect on plasma cholesterol levels in hamsters.

• Development and Reproduction
• /
• v.14 no.3
• /
• pp.185-197
• /
• 2010

The reproduction of animals is a means to maintain their species. The golden hamsters are seasonal breeders, and their reproduction is regulated by the photoperiod. The shifts of the sexual functions imply the changes of the protein expression, and those are reflected by the proteome. Thus the present study was to examine via two dimensional polyacrylamide gel electrophoresis (2d PAGE), the physiological changes and the alterations of protein expressions in hypothalamus upon the reproductive situation related to the pineal gland. Among the pineal intact animals, the reproductive functions were sustained in animals housed in long photoperiod (LP) but regressed in animals housed in short photoperiod. And those pinealectomized animals showed high sexual activities regardless of photoperiod. Ultimately they were branched into dichotomy, sexually active and inactive animals. Apart from the changes of physiological parameters upon the reproductive conditions, there were obvious differences in proteins extracted from the hypothalamus. The hypothalamus of LP animals presented high levels of enzymes which are involved in the production of energy, glycolysis and Krebs cycle. The increased energy might be related to the GnRH synthesis in hypothalamus and indirectly to the constant cell divisions in spermatogenesis. Taken together, the impacts of the photoperiodic information controlling reproduction could be observed through 2d PAGE. Therefore, the present results suggest the potential of biomarkers collectively to diagnose the fertility and the infertility by way of proteomics in organs with regard to the reproductive system, further could be applied to diagnose various diseases.

• Parasites, Hosts and Diseases
• /
• v.44 no.2 s.138
• /
• pp.163-166
• /
• 2006

The present study observed the resistance to reinfection with Clonorchis sinensis in various experimental animals including mice, guinea pigs, rabbits, and dogs, as well as rats and hamsters. The resistance rates to reinfection in rats, mice, hamsters, guinea pigs, rabbits, and dogs were 79.7%, 58.0%, -12.6%, 54.8%, 62.6%, and 6.0%, respectively. Worms recovered from reinfected rats and mice were immature, and significantly smaller than those from the primarily infected (P < 0.01), whereas those from other animals were fully matured to adults. These findings indicate that the protective response against reinfection with C. sinensis is prominent in rats and mice, and that they may be a good animal model to investigate the mechanism of resistance to reinfection with C. sinensis.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.9
• /
• pp.4597-4606
• /
• 2012

Cholangiocarcinoma (CCA) is an uncommon adenocarcinoma which arises from the epithelial cells of the bile ducts. The aim of the study was to investigate the cytotoxicity, toxicity, and anticancer activity of a crude ethanolic extract of ginger (Zingiber officinale Roscoe) against CCA. Cytotoxic activity against a CCA cell line (CL-6) was assessed by calcein-AM and Hoechst 33342 assays and anti-oxidant activity was evaluated using the DPPH assay. Investigation of apoptotic activity was performed by DNA fragmentation assay and induction of genes that may be involved in the resistance of CCA to anticancer drugs (MDR1, MRP1, MRP2, and MRP3) was examined by real-time PCR. To investigate anti-CCA activity in vivo, a total of 80 OV and nitrosamine (OV/DMN)-induced CCA hamsters were fed with the ginger extract at doses of 1000, 3000, and 5000 mg/kg body weight daily or every alternate day for 30 days. Control groups consisting of 10 hamsters for each group were fed with 5-fluorouracil (positive control) or distilled water (untreated control). Median $IC_{50}$ (concentration that inhibits cell growth by 50%) values for cytotoxicity and anti-oxidant activities of the crude ethanolic extract of ginger were 10.95, 53.15, and $27.86{\mu}g/ml$, respectively. More than ten DNA fragments were visualized and up to 7-9 fold up-regulation of MDR1 and MRP3 genes was observed following exposure to the ethanolic extract of ginger. Acute and subacute toxicity tests indicated absence of any significant toxicity at the maximum dose of 5,000 mg/kg body weight given by intragastric gavage. The survival time and survival rate of the CCA-bearing hamsters were significantly prolonged compared to the control group (median of 54 vs 17 weeks). Results from these in vitro and in vivo studies thus indicate promising anticancer activity of the crude ethanolic extract of ginger against CCA with the absence of any significant toxicity. Moreover, MDR1 and MRP3 may be involved in conferring resistance of CCA to the ginger extract.

• Korean Journal of Environmental Biology
• /
• v.20 no.3
• /
• pp.224-231
• /
• 2002

Photoperiod (length of light per day) is a major factor in regulating reproductive function in golden hamsters. The information of photoperiod is transmitted to the reproductive endocrine system by melatonin. Thus the effects of melatonin aye investigated in male golden hamsters exposed to photoperiods. Paired testicular weights were markedly reduced in the animals housed in short photoperiod $(SP,\le{12\;hours\;day^{-1})$ and injected with melatonin in the evening, but not in long photoperiod $(LP,\le{12.5}\;hours\;day^{-1})$ and injected with melatonin in the morning. The histological examination of regressed testes showed reduction of tubular lumen diameter including the numbers of cells and Leydig cell number. The mean values of both follicle stimulating hormone (FSH) and luteinizing hormone (LH) were also lowered in the sexually inactive animals than in the sexually active animals. Melatonin receptor was identified by reverse-transcription polymerase chain reaction (RT-PCR) and its expression was examined in various tissues to scrutinize the action site of melatonin. It turned out 309 nucleotides and was definitely expressed in hypothalamus and pituitary including spleen, retina, and epididymis. And gonadotropin releasing hormone (GnRH) gene, which is a key element in regulating reproduction, was identified by RT-PCR but the expression of GnRH was not modified by the treatment of melatonin. Taken together, photoperiod via melatonin indirectly affects reproductive endocrine system, possibly through the release of GnRH, not the synthesis of GnRH.

• Korean Journal of Food Science and Technology
• /
• v.39 no.2
• /
• pp.181-188
• /
• 2007

This study examined the effects of green tea extract supplementation (500 or 1,000 mg/kg b.w. per day) in conjunction with an atherogenic diet (10% coconut oil (w/w), 0.1% cholesterol) on plasma lipid composition, regression of pre-existing foam cells, and on the mRNA levels of hepatic HMG-CoA reductase and LDL receptor. Compared to groups fed only with the atherogenic diet, the addition of green tea extract to atherogenic diet-fed groups significantly down-regulated plasma triglyceride and total cholesterol levels, dose-dependently. Supplementation of 1,000 mg/kg b.w. of green tea extract with the atherogenic diet induced significant up-regulation of both HMG-CoA reductase and LDL receptor messenger RNA levels in liver as compared to the group receiving green tea extract supplementation at 500 mg/kg b.w. The F1B hamsters fed the atherogenic diet had greater foam cell accumulation compared to those fed a normal diet, or the atherogenic diet supplemented with green tea extract. Regression of fatty streak lesions was achieved by atherosclerosis in fat- and cholesterol-fed hamsters and this effect was associated with down-regulation of plasma cholesterol and up-regulation of hepatic LDL receptor expression.

• Applied Microscopy
• /
• v.38 no.3
• /
• pp.205-212
• /
• 2008

In this study morphological changes of the testes of golden hamsters treated with 6-aminonicotinamide (6-AN, 10 mg/kg body weight) in every two days were investigated using light and transmission electron microscopes. After the 7th injection of 6-AN, body weights of hamsters were significantly reduced, and the weight of testes were markedly reduced in the group of hamsters after 5th injections. Degeneration of seminiferous epithelium appeared first in the group receiving 5th injections, which were followed by severe degenerations after the 9th injection. In the degenerated seminiferous epithelium, deep vacuolization, and destruction of spermatogenic cells and Sertoli cells were also oberved. Multinuclear giant cells were also observed in the lumen of destructed seminiferous epithelium. But there were no edematous changes in the interstitial tissue, and the Leydig cells were found to be relatively intact. Therefore, these results show that 6-AN trigger severe morphological alteration of the spermatogenic cells and Sertoli cells, however Leydig cells are unaltered by 6-AN.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 1998.10a
• /
• pp.49-49
• /
• 1998

• Korean Journal of Veterinary Pathology
• /
• v.3 no.2
• /
• pp.83-85
• /
• 1999

Weekly subcutaneous injection of7 ,12-dimethylbenz[a]anthracene(DMBA) at a dose level of 0.25kg/mg body weight induced proliferative lesions in the spleen of syrian golden of syrian In addition, subcutaneous tumors at injection sites were observed. The splenic lesions included stromal hyperplasia and hacmangioma-like lesion.

• Development and Reproduction
• /
• v.21 no.4
• /
• pp.475-475
• /
• 2017