• 대한의생명과학회지
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• 제27권3호
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• pp.170-176
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• 2021

Thapsigargin (TG), a sarco/endoplasmic reticulum (ER) Ca²⁺-ATPase (SERCA) inhibitor, has been widely used as an agonist for platelet aggregation for decades. In this study, we investigated the effect of TG on the release of lactate dehydrogenase (LDH) for platelets and elucidated its mechanism. Platelet LDH release and platelet aggregation were increased by TG treatment; 1,000 nM of TG induced the complete lysis of platelets. Other agonists such as collagen (2.5 ㎍/mL), thrombin (0.1 U/mL), and ADP (10 mM) did not induce significant platelet LDH release despite platelet aggregation. Finally, we investigated the effects of pharmacological inhibitors on TG-induced platelet aggregation and LDH release. SP600125, a JNK inhibitor, and LY294002, a PI-3K inhibitor, inhibited TG-induced platelet LDH release but not platelet aggregation. Forskolin, an adenylyl cyclase activator, also inhibited LDH release without affecting platelet aggregation by TG. These results suggest that the TG-induced platelet aggregation was accompanied by LDH release but regulated by a different signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제2권6호
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• pp.753-761
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• 1998

Preconditioning of a heart with small doses of catecholamines induces a tolerance against the subsequent lethal ischemia. The present study was performed to find a specific receptor pathway involved with the catecholamine preconditioning and to test if adenosine plays a role in this cardioprotective effect. Isolated rat hearts, pretreated with small doses of ${\alpha}-\;or\;{\beta}-adrenergic$ agonists/antagonists, were subjected to 20 minutes ischemia and 20 minutes reperfusion by Langendorff perfusion method. Cardiac mechanical functions, lactate dehydrogenase and adenosine release from the hearts were measured before and after the drug treatments and ischemia. In another series of experiments, adenosine $A_1\;or\;A_2$ receptor blockers were treated prior to administration of adrenergic agonists. Pretreatments of a ${\beta}-agonist,\;isoproterenol(10^{-9}{\sim}10^{-7}\;M)$ markedly improved the post-ischemic mechanical function and reduced the lactate dehydrogenase release. Similar cardioprotective effect was observed with an ?-agonist, phenylephrine pretreatment, but much higher $concentration(10^{-4}\;M)$ was needed to achieve the same degree of cardioprotection. The cardioprotective effects of isoproterenol and phenylephrine pretreatments were blocked by a ${\beta}_1-adrenergic$ receptor antagonist, atenolol, but not by an ${\alpha}_1-antagonist,$ prazosin. Adenosine release from the heart was increased by isoproterenol, and the increase was also blocked by atenolol, but not by prazosin. A selective $A_1-adenosine$ receptor antagonist, 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX) blocked the cardioprotection by isoproterenol pretreatment. These results suggest that catecholamine pretreatment protects rat myocardium against ischemia and reperfusion injury by mediation of ${\beta}_1-adrenergic$ receptor pathway, and that adenosine is involved in this cardioprotective effect.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.398-403
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• 1999

In our previous studies, we reported that hybridoma B-lymphocytes can be used to determine the virulence of Listeria species in an in vitro cytotoxicity assay. Here, we examined the cytopathic effect, i.e., membrane damage and the nature of cell death induced by Listeria monocytogenes on murine hybridoma B-lymphocytes (Ped-2E9). Membrane damage was assessed by microscopic analyses and by measuring the release of intracellular alkaline phosphatase(AP) and lactate dehydrogenase (LDH). Cell death was determined by DNA fragmentation analyses using agarose gel electrophoresis. Infection by listeriolysin O (LLO)-producing L. monocytogenes strains induced substantial amounts of AP and LDH release from Ped-2E9 hybridoma B-cells, suggesting severe membrane damage in these cells, while an LLO-negative L. monocytogenes mutant strain had no effect. An LLO-producing recombinant L. innocua ($prifA^+hly^+$) strain also induced high AP and LDH release and cytopathic changes in Ped-2E9 cells. Light or scanning electron microscopic examination revealed L. monocytogenes mediated membrane destabilization, pore formation, intense cytoplasmic granulation, bleb formation, and lysis of Ped-2E9 cells. LLO-producing L. monocytogenes and L. innocua ($prifA^{+}hly{^}+$) also induced ladder-like DNA fragmentation in Ped-2E9 cells. Collectively, these results suggest that L. monocytogenes, specifically LLO-producing strains, can induce a severe cytopathic effect leading to apoptosis in hybridoma B-lymphocytes (Ped-2E9).

• 대한의생명과학회지
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• 제7권3호
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• pp.127-131
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• 2001

This study was undertaken to examine the effect of amino acids on anoxia-induced cell injury in rabbit renal cortical slices. In order to induce anoxic cell injury, slices were exposed to a 100% $N_2$ atmosphere and control slices were exposed to 100% $O^2$. Irreversible cell injury was estimated by measuring lactate dehydrogenase (LDH) release and alterations in renal cell function were examined by measuring p-aminohippurate (PAH) uptake. Anoxia caused the increase in LDH release in a time-dependent manner. Glycine and glutathione almost completely prevented anoxia-induced LDH release. Of amino acids tested, glycine and alanine exerted the protective effect against anoxia-induced cell injury. However, asparagine with amide side chain, leucine and valine with hydrocarbon side chain, and basic amino acids (lysine, histidine, and arginine) were not effective. Anoxia-induced inhibition of PAM uptake was prevented by glycine. ATP content was decreased by anoxia, which was not affected by glycine. Anoxia-induced depletion of glutathione was significantly prevented by glycine. These results suggest that neutral amino acids with simple structure exert the Protective effect against anoxia-induced cell injury the involvement of specific interaction of amino acids and cell structure.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1670-1674
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• 2001

To understand molecular mechanisms that regulate deposition and release of intramuscular fat, a fasting-induced clone was identified by differential screening from cDNA library of adipose tissues of Korean cattle. The clone had a total length of 1,319 nucleotides coding for 334 amino acids. It was identified as one encoding L-lactate dehydrogenase H chain (LDH-B). Comparison of the deduced amino acid sequences of bovine LDH-B with those of pig, human, rat, and mouse showed 98%, 98%, 97%, and 96% identity, respectively. Food deprivation for 48 h increased mRNA levels of LDH-B gene in adipose tissues of Korean cattle compared to fed- and 6 h refed- tissues. The expression of obese mRNA was examined for individual adipose tissue from several fat depots. Fasting induced expression of LDH-B gene in subcutaneous adipose tissues, but it did not affect expression levels in abdominal, perirenal and intramuscular tissues. Results demonstrate that induction of LDH-B gene during fasting may represent a metabolic shift from anaerobic state to aerobic predominance in fasted adipose tissues and that its responses to fasting are different among several adipose tissues.

• 한국환경보건학회지
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• 제21권4호
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• pp.87-95
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• 1995

The concentrations of cadmium, metallothionein(MT), superoxide dismutase(SOD), and lactate dehydrogenase(LDH) were investigated in liver and kidney of rats which were fed the water containing 100 ppm cadmium chloride with basal diet and 5% Agaricus bisporus diet during 16 weeks. Cadmium concentrations in liver and kidney increased during 16 weeks, and there were significantly higher accumulation of cadmium in the kidney than in the liver. The concentrations of MTs in liver and kidney decreased linearly during 16 weeks, but there was no significant difference between control and experimental group. MT concentrations of liver were significantly higher than those of kidney. The superoxide dismutase activities and lactate dehydrogenase activities were not affected by the diet, but there was a significant difference by the duration of administration. These data indicate that the kidney is a major target organ of chronic cadmium poisoning, and suggest that Cd-induced hepatic injury, via release of Cd-MT, may play an important role in the nephrotoxicity. In conclusion, induction of MT occurs in both the liver and the kidney after administration of $CdCl_2$. However, the kidney is less responsive than the liver to the induction of MT by cadmium, which may contribute to making the kidney the target organ of toxicity during chronic Cd exposure.

• 대한한방내과학회지
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• 제28권3호
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• pp.502-509
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• 2007

Objectives : Folium perillae (FP) can relieve superficial pathogenic factors to dissipate cold and promote the circulation of qi and regulate the function of the stomach and is often used for interior qi-stagnation. We hypothesized that FP could rescue cerebral ischemia in rats. Methods : The present study was carried out to investigate the effects of FP on cerebral ischemia in terms of regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in rats. Finally, lactate dehydrogenase (LDH) release was investigated, too. Results : In this study, treatment with FP elevated rCBF and MABP levels in dose-dependent manner. Pre-treatment with indomethacin, an inhibitor of cyclooxygenase, inhibited rCBF increase induced by FP effectively. However, FP did not affect stability during cerebral reperfusion. Finally, FP significantly inhibited LD H activity in vitro Conclusions : These results suggest that FP is useful to treat patient with diseases related to cerebral ischemia, because FP can increase rCBF and MABP.

• 대한한의학회지
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• 제20권1호
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• pp.122-131
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• 1999

This study was carried out to investigate whether water extract of Sagunja-Tang and its composing herbs have the inhibitory effects on cytotoxicity and lipid peroxidation induced by oxidant in rat renal cortical slices. Cytotoxicity was estimated by measuring lactate dehydrogenase (LDH) activity and lipid peroxidation was examined by measuring malondialdehyde (MDA). a product of lipid peroxidation. When rat renal cortical slices were treated with tert-butylhydroperoxicle (t-BHP) of 1 mM and water decocted herbs. LDH release from the slices was inhibited in dose dependent manner at low concentrations of herbs. It shows that herbs can reduce cytotoxicity, but overdose of herbs can be toxic to the slices. And MDA measurements show each herb has its own activities of preventing cytotoxicity from oxidants. So further studies should be followed to make clear the mechanisms of anti-oxidative effects of herbs.

• 한국식품영양과학회지
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• 제27권2호
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• pp.344-349
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• 1998

The purpose of this study was carried out to investigate the effect of scoparone(6, 7-dimethoxyco-umarin) on liver function. Sprague-Dawley rats were treated with scoparone at a dose of 20mg/kg body weight for 5 days. Hepatic bile flow, liver weight, BSP(bromosulfophthalein) biliary excretion, alanine aminotransferase(ALT) and aspartate aminotransferase(AST) activities, malondialdehyde production and lactate dehydrogenase(LDH) release were assayed. Among them, ALT and AST activities, malondialdehyde production and LDH release were assayed by using primary hepatocyte cultures at a concentration of 0.1mg/ml. Scoparone treatment had no effect on liver weight and hepatic bile flow. Scoparone treatment not only increased BSP biliary excretion, but also recovered the decreased BSP biliary excretion by CCl4, Also scoparone significantly decreased with the increases of ALT and AST activities, malondialdehyde production and LDH release induced by CCl4. These results suggested that scoparone could protect the liver damage by chemicals via promoting the liver excretory function.

• 치위생과학회지
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• 제2권1호
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• pp.25-29
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• 2002

본 연구에서는 분자량 78,000과 9,600의 poly-L-lysine(PLL)이 일차배양된 햄스터의 기관표면 상피세포로부터의 뮤신유리에 어떠한 영향을 미치는지를 검증하고자 하였다. 완전히 다 자란 배양세포에 $^3H$-glucosamine을 함유하는 완전 배양액을 첨가하고 24시간 배양함으로써 배양세포 중의 뮤신에 대사적 방사선 표지를 완결한 후 다양한 농도의 PLL을 30분간 처리하고, 유리되는 방사성 뮤신의 함량을 측정하였다. PLL에 의한 세포독성 발현여부를 검증하기 위하여 PLL 처리 후 배양세포로부터 유리되어 배양액 중에 존재하는 Lactate Dehydrogenase(LDH)의 활성을 측정하였다. 실험 결과, PLL은 분자량 78,000 및 9,600의 두 물질 공히 용량 의존적으로 뮤신유리를 억제하였다. 그러나 세포독성의 지표인 LDH 유리에 대한 영향은 PLL 9,600의 경우에는 유의성이 없었으나, PLL 78,000의 경우에는 현저한 유리 증가를 보였다. 이러한 결과는 PLL의 경우, 분자량이 10,000 이하의 범위에서 세포독성을 발현하지 않으면서도 뮤신유리를 특이적으로 억제할 가능성을 제시하고 있으며, 동시에 PLL이 기도점액 과다분비 현상을 연구함에 있어서 유용한 실험수단으로 이용될 가능성도 제시하고 있는 것이다.