• Toxicological Research
• /
• v.2 no.1
• /
• pp.1-7
• /
• 1986

Procarcinogen induced DNA single-strand breaks and unschduled DNA synthesis were measured in primary rat hepatocytes culture. For DNA single-strand breaks assay, rat liver DNA was prelabeled by injection 3H-thymidine during the peak of DNA synthesis following partial hepatectomy. Hepatocytes were isolated from the rat 2 weeks after surgery by a collagenase perfusion techinique and maintained as monolayers in serum free medium on collagen-coated culture dishes. DNA sigle-strand breaks were measured by the alkaline elution techinique.

• The Korean Journal of Pharmacology
• /
• v.2 no.1 s.2
• /
• pp.41-48
• /
• 1966

The author studied the adrenotropic receptors of the non-pregnant uteri of the rabbit and rat, using epinephrine (alpha and beta activator), phenoxybenzamine(alpha blocking agent) and nethalide (beta blockade), and obtained the following results: 1. The spontaneous motility of isolated non-pregnant uteri from rabbits were stimulated by epinephrine, whereas that of isolated non-pregnant rat uterus was inhibited by epinephrine. 2. Both alpha and beta adrenergic receptors were present in the uterine muscle of both animals. 3. In the non-pregnant rabbit uterus, alpha receptors were predominant, whereas in the non -pregnant rat uterus, beta receptors preponderated over alpha receptors.

• Toxicological Research
• /
• v.22 no.4
• /
• pp.323-328
• /
• 2006

Global gene expression profile was analyzed by microarray analysis of rat liver RNA after acute acetaminophen (APAP) administration. A single dose of 1g/kg body weight of APAP was given orally, and the liver samples were obtained after 24, 48 h, and 2 weeks. Histopathologic and biochemical studies enabled the classification of the APAP effect into injury (24 and 48 h) and regeneration (2 weeks) stages. The expression levels of 4900 clones on a custom rat gene microarray were analyzed and 484 clones were differentially expressed with more than a 1.625-fold difference(which equals 0.7 in log2 scale) at one or more time points. Two hundred ninety seven clones were classified as injury-specific clones, while 149 clones as regeneration-specific ones. Characteristic gene expression profiles could be associated with APAP-induced gene expression changes in lipid metabolism, stress response, and protein metabolism. We established a global gene expression profile utilizing microarray analysis in rat liver upon acute APAP administration with a full chronological profile that not only covers injury stage but also later point of regeneration stage.

• Biomolecules & Therapeutics
• /
• v.12 no.3
• /
• pp.185-188
• /
• 2004

The purpose of this study is to evaluate the effect of cigarette smoke condensate (CSC) on toxification/detoxification metabolic pathway in primary cultured rat hepatocytes. We measured the activities of cytochrome P450 monooxygenases (CYP450s) and UDP-glucuronyltransferase, sulfotransferase and glutathione-S-transferase in CSC-treated rat hepatocytes. CSC significantly increased the activities of hepatic CYP4501A1 and CYP4501A2 to 7.5 fold and 1.6 fold respectively, compared with control level. However, CSC did not affect the activities of conjugation enzymes. We a1so examined if treatment of CSC could change thc cytotoxicity of acetaminophen (AA) through modulation of metabolizing enzymes. In rat hepatocytes, pretreatment with CSC potentiated the cytotoxicity of AA. This result indicates that potentiation of AA toxicity by CSC pretreatment may be related to induction of CYP4501A1 and CYP4501A2.

• Journal of Chest Surgery
• /
• v.21 no.2
• /
• pp.231-239
• /
• 1988

Currently numerous methods are in use for myocardial hypothermia as a myocardial preservation modality for cardiac operation. During cardiac ischemia after crystalloid cardioplegia[4C GIK solution], topical cold saline[Group I, a=9], topical ice slush[Group II, n=9] and topical ice chip[Group III, a=10] have been compared for myocardial surface cooling in the isolated rat heart model of cardiopulmonary bypass. During postischemic period, hemodynamic functions[aortic flow, coronary flow, peak aortic pressure and heart rate], biochemical enzymatic activities and cellular injuries with electron microscope were evaluated in this isolated rat heart perfusion model. Postischemic aortic flow, cardiac output and peak aortic pressure in Group I and Group II recovered better than Group III.[p< 0.05] Postischemic creatine kinase and lactate dehydrogenase leakages in Group II and Group III increased more than Group l and postischemic mitochondrial swelling in Group III was more severe than Group I, and Group II.[p< 0.05] These results suggest that topical cold saline was the better method than topical ice slush or topical ice chip as a myocardial preservation modality in the isolated rat heart model of cardiopulmonary bypass.

• Korean Journal of Veterinary Research
• /
• v.40 no.4
• /
• pp.661-664
• /
• 2000

The present study was carried out to reveal the role of ${\gamma}$-aminobutylic acid(GABA) during postnatal period in rat. The suprachiasmatic nucleus(SCN) of hypothalamus has been known as the regulation center of circadian rhythm in the mammalians. In this study, we could find many GABAergic terminals in the SCN from day 1 to day 7 after birth. On the basis of these results, it can be said there are some kinds of inhibitory effects by GABA to the light stimulation of newborn rat.

• Applied Microscopy
• /
• v.27 no.4
• /
• pp.347-355
• /
• 1997

These studies were performed to observe the morphological changes of synapses in the visual cortex of rat during early postnatal development. Specimens of the visual cortex were taken from rats (Sprague Dawley) at 1, 3, 7, 14 and 21 days of age, and prepared for silver impregnation and electron microscopy. The number of synapse and the length of postsynaptic thickening were increased progressively with age, especially 14 and 21 days. The number of dendritic spine was increased conspicuously on postnatal days 14-21. And asymmetic, curved and axo-spinous synapses were increased markedly at the same ages. The present findings suggest that spurt of synaptogenesis in the rat visual cortex occurs during early postnatal development, especially in second to 3rd week period and asymmetric and/or curved axo-spinous synapse is a matured form of synapse with advanced age.

• Mass Spectrometry Letters
• /
• v.2 no.1
• /
• pp.20-23
• /
• 2011

The purpose of this study is to investigate the in vitro metabolism of hesperetin, a bioflavonoid. Hesperetin was incubated with rat liver microsomes in the presence of NADPH and UDP-glucuronic acid for 30 min. The reaction mixture was analyzed by liquid chromatography-ion trap mass spectrometer and the chemical structures of hesperetin metabolites were characterzed based on their MS/MS spectra. As a result, a total of five metabolites were detected in rat liver microsomes. The metabolites were identified as a de-methylated metabolite (eriodictyol), two hesperetin glucuronides, and two eriodictyol glucuronides.

• The Korean Journal of Zoology
• /
• v.37 no.2
• /
• pp.255-261
• /
• 1994

Recombinant human pBrathyriod hormone related peptide (1-341 (rhPTHrP) has been known to stimulate bone resorption in intact bone tissue culture system. Osteoclast has been known as a primary responsible cell for bone resorption. To examine the effect of rhPTHrP on this cell, we employed disaggregated rat osteodast culture. As a result, we found that rhPTHrP sisnificBntly elevates both the number and total area of resorbed pits in this culture. On the other hand, the conflicting results between disagsregated rat osteoc13st culture and Ca2+-deficient hen osteoclast culture system have been a big obstacle for the progress of bone research. To verify the differences between rat 3nd chick osteoclast system, we performed the same experiment using chick embryonic osteoclast. Since the similar results were obtained from the disaggregated chick osteoclast culture, the discrepancy between chick and rat osteoclast culture study seemed to be due to the difference in culture method, rather due to the species-difference.

• YAKHAK HOEJI
• /
• v.34 no.3
• /
• pp.147-154
• /
• 1990

In order to clarify mechanism of the formation of cinnamaldehyde (CNA) in incubation mixtures of tranylcypromine (TCP) with rat liver microsomes, the CNA formed under various incubation conditions were analyzed. For the purpose, HPLC method of the analysis of CNA was developed. The formation of CNA was found to be dependent on the incubation time and the amounts of microsomes added. In addition, exclusion of NADPH or NADP of NADPH-generating system in incubation mixtures resulted in the formation of markedly decreased amounts of CNA to 8.5 and 2.4%, respectively, relative to the amounts formed each in a standard system. The small amounts measured were comparable to those formed by incubation without microsomes or with boiled microsomes. The results clearly suggested that CNA is a metabolic product of TCP by rat liver microsomes though further studies are needed to suggest details of the steps to the formation of CNA from TCP and of the enzymatic entities involved in the formation of CNA.