• The Korean Journal of Physiology and Pharmacology
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• v.3 no.5
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• pp.507-512
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• 1999

Contribution of prostaglandins $D_2,\;E_2\;and\;I_2\;(PGD_2,\;PGE_2\;and\;PGI_2)$ on the regulation of ATP-sensitive $K^+$ channel $(K_{ATP}\;channel)$ was investigated in isolated single rat ventricular cardiac myocytes using the patch clamp technique. $PGD_2,\;PGE_2\;and\; PGI_2$ did not affect $K_{ATP}$ channel activity in the inside-out patch, but increased channel activity in a dose-dependent manner when the channel activities were attenuated by the administration of 100 ${\mu}M$ ATP to the internal solution in the inside-out patch. Channel activations by the prostaglandins were abolished by 50 ${\mu}M$ glibenclamide, a $K_{ATP}$ channel blocker. Dose-response curves of relative channel activity against the ATP concentrations of internal solution in the inside-out patch were shifted to the right in the presence of those three prostaglandins. The rank order of the channel stimulatory potencies $(as\;IC_{50}\;for\;ATP)$ calculated from the dose-response curves were $PGI_2\;>\;PGD_2\;>\;PGE_2.$ Conductance of the channel was not changed by those three prostaglandins. In conclusion, we suggest that prostaglandins $D_2,\;E_2\;and\;I_2$ are involved in the regulation of $K_{ATP}$ channel activity in certain circumstances, and that those three prostaglandins may cause myocardial relaxation by opening $K_{ATP}$ channels, thus protecting the heart from ischema.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.506-511
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• 1992

The Prostaglandins were derivatized rapidly with monodansyl cadaverine as a fluorophore in mild conditions. The carboxylic moiety of prostaglandins was activated with diethyl phosphorocyanidate and successively coupled with fluorophore in dimethylformamide at room temperature. The labeling yield was reached about 95% at 15 min using arachidic acid $(C_{20:0})$ as a test sample. This derivative showed constant fluorescent intensity at $4^{\circ}C$ for 180 days. The derivatives of prostaglandins were shown high solvent selectivity with tetrahydrofuran in reversed-phase column. therefore, these derivatives could be successfully separated on YMC pack A-212(S-5 120A C8) column in tetrahydrofuran-based eluents. The detection limits of these derivatives was ca. 500 fmol and determination limits was ca. 5 pmol as injected amount in fluorescent detection $({\lambda}ex.\;340\;nm,\;{\lambda}em.\;520\;nm)$. In this method, the ranges of recovery and coefficient of variation were $93.6{\sim}102.7%$ and $4.3{\sim}5.8%$, respectively.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.311-319
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• 1988

This study was designed to elucidate the effects of iron, a well known catalyst of lipid peroxidation, on the contents of phospholipids, unsaturated fatty acids composed in phospholipid molecules and their derivatives, prostaglandins, and the composition changes of fatty acids contained in phospholipids. Iron decreased the contents of phospholipids and its components of unsaturated fatty acids. Catalytic action of iron decreased the composition rates of linoleate and linolenate composed in phospholipid molecules, while that of arachidonate was inclined to increase. The content of arachidonate was increased and that of prostaglandins was decreased without regard to increase the precursor of prostaglandins. It may be concluded that the decreases of prostaglandins and the increase of arachidonate are due to inhibition of the activities of enzyme systems responsible for prostaglandin synthesis by lipid peroxides produced by the catalyst of iron.

• Clinical and Experimental Reproductive Medicine
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• v.3 no.1
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• pp.21-25
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• 1976

• Journal of Nutrition and Health
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• v.24 no.2
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• pp.97-103
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• 1991

The increase in alcohol consumption level has been noticed in Korea recently. Alcohol appreciably inhibits cell mediated immunity and this may contribute to the high prevalence of serious infection such as pulmonary tuberculosis among alcoholic subjects. The present study was undertaken to examine the effect of ethanol on the cyclooxygenase metabolites of human monocyte in vitro. Monocytes were activated with 800 units of gamma interferon(IFN-${\gamma}$) for 3 days following apply of Ficool-hypaque density gradient and gelatin coated flasks for separation of monocytes. Ethanol with addition of 100mM, 300mM and 600 mM for 30 minutes to 106 monocytes with/without previous IFN-${\gamma}$ treatment caused a dose dependent decrease in the production of thromboxane B2, 6-keto-PGE1$\alpha$ and PGE2 by radioimmunoassay at 6 hours after ethanol treatment. Quite different from the findings after 6 hours there was dose dependent increase in three prostaglandins without IFN-${\gamma}$ treatment after 24 hours of incubation. With previous treatment of IFN-${\gamma}$ reduced productions of three prostaglandins at 24 hours than control is spite of ethanol stimjulation. These findings show that IFN-${\gamma}$ can inhibit alcohol induced derangement of arachidonic acid metabolism of monocytes.

• Journal of Yeungnam Medical Science
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• v.17 no.1
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• pp.1-11
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• 2000

Inhibition of cyclooxygenase(COX), and thus prevention of the formation of prostaglandins, provided a unifying explanation of the therapeutic and toxic actions of nonsteroidal anti-inflammatory drugs (NSAIDs). Recently, the discovery of the two isoforms of COX was made by molecular biologists studying neoplastic transformation in chick embryo cells. The constitutive enzyme, COX-1, is obviously responsible for the production of prostaglandins involved in housekeeping functions such as maintenance of integrity of the gastric mucosa, renal blood flow and platelet aggregation. The inducible form of COX (COX-2) is responsible for the formation of prostaglandins that pathologically affects inflammation, pain and fever. Clearly, all the experimental and clinical data support the hypothesis that the beneficial effects of NSAIDs are due to inhibition of the COX-2 enzyme, whereas the gastrotoxicity is due to inhibition of COX-1. The cox-2/COX-1 ratios of the NSAIDs in common use have been measured and compared with epidemiological data on their side effects. There is little evidence to suggest that one NSAID is clearly more effective than another, But substantial individual variability is present with respect to the pharmacology and pharmacokinetics of these drugs: therefore it is essential to adjust the dosage and choose specific drug to the patient's response.

• Clinical and Experimental Reproductive Medicine
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• v.3 no.2
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• pp.3-12
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• 1976

• The Korean Journal of Pharmacology
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• v.13 no.2
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• pp.35-39
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• 1977

Cyclic adenosine monophosphate (cAMP), known as a versatile regulator of cellular processes and as a secondary messenger of various hormones and other biogenic agents, such as prostaglandins and histamine, induced prompt and transient antidiuresis followed by mild natriuresis and diuresis, when it was administered into the lateral ventricle of the rabbit in doses ranging from $100\;{\mu}g$ to 1 mg. The initial antidiuresis was brought about by the systemic hypotension, whereas the secondary diuresis seemed to be resulted from the decreased tubular reabsorption of sodium, suggestive of participation of certain endogenous natriuretic agent. This observation suggests that cAMP might be involved in the center-mediated renal action of prostaglandins.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.29-32
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• 1992

The effects of prostaglandins (PG) and indomethacin, a PG synthesis inhibitor, on ovulation in the perfused fowl ovary were studied. Laying hens were killed by cutting the jugular vein 18-19 h before expected ovulation of the second follicle of a clutch sequence. The cannulated ovary was dissected free and connected with a recycling perfusion apparatus. Agents to be studied for their effects on ovulation were added to the perfusion fluid. $PGF_{2{\alpha}}$ at 0.1 and 1 mg/l induced ovulation, with a success rate of 25% and 30%, respectively. The same doses of $PGE_2$ were effective at 60% and 63%, respectively. Indomethacin partially blocked gonadotrophin-induced ovulation. It is suggested that PGs may play a supportive role in the process of follicular rupture in the domestic fowl.

• The Korean Journal of Pharmacology
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• v.11 no.1 s.17
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• pp.61-79
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• 1975

The recent knowledge about the effects and the biological roles of prostaglandins(PGs) in the female reproductive system were reviewed on the following view points in detail and the authors also argued on the efficacy and reliability for the induction of labour and therapeutic abortions in midtrimester pregnancy. 1. The actions of PGs on the myometrium in vivo and in vitro and the effects of ovarian hormones on the actions of PGs. 2. The actions of PGs on the fallopian tube. 3. The role of PGs in the initiation of menstrual bleeding and dysmenorrhea. 4. The biological action of PGs on the mechanism of labour and parturition. 5. The efficacy and reliability of PGs for therapeutic abortion in the first and midtrimester pregnancy. 6. The biological role of PGs in the activity and life-span of corpus luteum.