• 대한의생명과학회지
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• 제10권4호
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• pp.375-383
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• 2004

It has been reported that osteoporosis induced by the deficiency of estrogens in menopause is associated with the unbalance of Ca/sup 2+/ and Pi levels. Proximal tubule is very important organ to regualte Ca/sup 2+/ and Pi level in the body. However, the effect of estrogens on Ca/sup 2+/ and Pi regulation was not elucidated. Thus, we examined the effect of 17-β estradiol (E₂) on Ca/sup 2+/ and Pi uptake in the primary cultured rabbit renal proxiaml tubule cells. In the present study, E₂(> 10/sup -9/M) decreases Ca/sup 2+/uptake and stimulates Pi uptake over 3 days. E₂-induced decrease of Ca/sup 2+/ uptake and stimulation of Pi uptake were blocked by actinomycin D (a gene transcription inhibitor), cycloheximide (a protein synthesis inhibitor). tamoxifen, and progesterone (estrogen receptor antagonists). E₂-induced decrease of Ca/sup 2+/ uptake and stimulation of Pi uptake were blocked by SQ22536 (an adenylate cyclase inhibitor), Rp-cAMP (a cAMP antagonist), and PKI (a protein kinase A inhibitor). Indeed, E₂ increased cAMP formation. In addition, E₂-induced decrease of Ca/sup 2+/ uptake and stimulation of Pi uptake were blocked by staurosporine, H-7, and bisindolylmaleimide I (protein kinase C inhibitors) and E₂ translocated PKC from cytoslic fraction to membrane fraction. In conclusion, E₂ decreased Ca/sup 2+/ uptake and stimulated Pi uptake via cAMP and PKC pathway in the PTCs.

• Animal cells and systems
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• 제6권1호
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• pp.69-74
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• 2002

Recent evidence has suggested that trunk neural crest cell generally assumed to have equivalent differentiation potentials, demonstrate differentiation bias along the anterior/posterior axis. In amphibian and fish, neural crest cells give rise to three chromatophore types, melanophores, xantho-phores, and iridophores. Each pigment cell type has distinct characteristics but there is speculation about the cellular plasticity that exists among them. Neural crest cells migrate along specific routes, ventromedially and dorsolaterally. Neural crest cells that travel dorsolaterally are the first cells to begin migration in the axolotl and are the major contributors to the visible pigment pattern. Many factors and mechanisms that are responsible for guiding migratory neural crest cells along potential pathways or determining their fate remain unknown. A single lineage of the crest, which becomes restricted to one of the three pigment cell types, gives us the opportunity to examine the existence of neural crest stem cell populations and cellular plasticity. Study presented here showed results from recent in vitro studies designed to identify parameters influencing differentiation events of individual neural crest-derived pigment cell lineages. Melanophore production from neural crest explants originating from different levels along the anterior/posterior axis of wild type-axolotl embryos were compared and demonstrate that the differentiation of melanophores is enhanced in subpopulation of neural crest treated with forskolin. Forskolin (an adenylate cyclase activator) increases intracellular CAMP concentration and eventually activates the protein kinase-A signaling pathway. Melanophore number, melanin content, and tyrosinase activity in explants taken from the anterior-most region of the crest increased significantly in response to forskolin treatment. This study suggests implications of region specific influences and developmental regulation in the development of pigment pattern.

• 대한수의학회지
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• 제39권6호
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• pp.1073-1080
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• 1999

Previous studies suggested that the inhibition of thyroxine ($T_4$) release by ${\alpha}_1$-adrenoceptor and muscarinic receptor stimulation results in activated protein kinase C (PKC) from mouse and guinea pig thyroids. In the present study, the effect of carbachol, methoxamine, phorbol myristate acetate (PMA), and R59022 on the release of $T_4$ from the mouse, rat, and guinea pig thyroids was compared to clarify the role of PKC in the regulation of the release of $T_4$. The thyroids were incubated in the medium containing the test agents, samples of the medium were assayed for $T_4$ by EIA kits. Forskolin, an adenylate cyclase activator, chlorophenylthio-cAMP sodium, a membrane permeable analog of cAMP, and isobutyl-methylxanthine, a phosphodiesterase inhibitor, like TSH (thyroid stimulating hormone), enhaced the release of $T_4$ from the mouse, rat, and guinea pig thyroids. Methoxamine, an ${\alpha}_1$-adrenoceptor agonist, inhibited the TSH-stimulated release of $T_4$ in mouse, but not rat and guinea pig thyroids. In contrast, carbachol, a muscarinic receptor agonist, inhibited the release of $T_4$ in guinea pig, but not mouse and rat thyroids. These inhibition were reversed by prazosin, an ${\alpha}_1$-adrenoceptor antagonist or atropine, a muscarinic antagonist or $M_1$- and $M_3$-muscarinic antagonists, in mouse or guinea pig thyroids. In addition, staurosporine, a PKC inhibitor, reversed methoxamine or carbachol inhibition of TSH stimulation. Furthermore, PMA, a PKC activator, and R59022, a diacylglycerol (DAG) kinase inhibitor, inhibited the TSH-stimulated release of $T_4$ in mouse, rat, and guinea pig thyroids. These inhibition were blocked by staurosporine. These findings suggest that the activation of receptor or DAG inhibits TSH-stimulated $T_4$ release through a PKC-dependent mechanism in thyroid gland.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1216-1226
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• 2015

GlxR is considered as a global transcriptional regulator controlling a large number of genes having broad physiological aspects in Corynebacterium glutamicum. However, the expression profile revealing the transcriptional control of glxR has not yet been studied in detail. DNA affinity chromatography experiments revealed the binding of transcriptional regulators SucR, RamB, GlxR, and a GntR-type protein (hereafter denoted as GntR3) to the upstream region of glxR. The binding of different regulators to the glxR promoter was confirmed by EMSA experiments. The expression of glxR was analyzed in detail under various carbon sources in the wild-type and different mutant strains. The sucR and gntR3 deletion mutants showed decreased glxR promoter activities, when compared with the wild type, irrespective of the carbon sources. The promoter activity of glxR was derepressed in the ramB deletion mutant under all the tested carbon sources. These results indicate that SucR and GntR3 are acting as activators of GlxR, while RamB plays a repressor. As expected, the expression of glxR in the cyaB and glxR deletion mutants was derepressed under different media conditions, indicating that GlxR is autoregulated.

• The Korean Journal of Physiology and Pharmacology
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• 제6권5호
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• pp.261-267
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• 2002

The aim of the present study was to investigate the interaction of $estradiol-17{\beta}-bovine$ serum albumin $(E_2-BSA)$ and calcitropic hormones, such as parathyroid hormone, calcitonin, and vitamin D, in regulation of $Ca^{2+}$ uptake in primary cultured renal proximal tubule cells. Statistically significant increase in $Ca^{2+}$ uptake was found from 2 hours after $(E_2-BSA)\;(10^{-9}\;M)$ treatment, while $estradiol-17{\beta}\;(10^{-9}\;M)$ did not affect. Treatment of the cells with $(E_2-BSA)\;(10^{-9}\;M)$ together with parathyroid hormone (PTH) $(10^{-8}\;M),$ vitamin D $(10^{-8}\;M),$ or calcitonin $(10^{-8}\;M)$ significantly stimulated $Ca^{2+}$ uptake by 32.50%, 29.30%, or 27.75%, respectively, compared with the control. However, calcitropic hormones did not exhibit any synergistic effect on the E2-BSA-induced stimulation. $E_2-BSA$ significantly increased cAMP generation and PKC activity. The stimulatory effect of cotreatment of $E_2-BSA$ and PTH or vitamin D was blocked by SQ22536 (an adenylate cyclase inhibitor) and staurosporine (a PKC inhibitor), but the effect of cotreatment of $E_2-BSA$ and calcitonin was not blocked. Furthermore, 8-Br-cAMP and TPA (an artificial PKC promoter) increased $Ca^{2+}$ uptake by 25.51% and 16.47%, respectively, compared with the control. In conclusion, $E_2-BSA$ combined with calcitropic hormones regulated $Ca^{2+}$ uptake partially via cAMP and PKC-dependent mechanisms in renal proximal tubule cells.

• 대한약리학회지
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• 제30권3호
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• pp.263-272
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• 1994

흰쥐 해마(hippocampus)에서 acetylcholine (ACh) 유리에 미치는 $A_{1}-adenosine$ 수용체의 post-receptor 기전에 관한 지견을 얻고자 하여 $^3H-choline$으로 평형시킨 해마 slice를 사용하여 $^3H-ACh$ 유리에 미치는 여러가지 약물들의 영향을 관찰하였다. Adenosine $(0.3{\sim}300\;{\mu}M)$은 전기자극(3Hz, 2 ms, 5 $VCm^{-1}$, 구형파)에 의한 ACh 유리를 용량 의존적으로 감소 시켰으며, 이러한 효과는 $A_1-adenosine$ 수용체의 선택적 차단제인 8-cyclopentyl-1, 3-dipropylxanthine $(2\;{\mu}M)$에 의해 차단됨을 볼 수 있었다. G-단백 억제제인 N-ethylmaleimide (NEM, 10과 $30\;{\mu}M$)는 그 자체에 의하여 자극유발성 ACh 유리를 증가시켰으며, adenosine의 효과는 NEM 전처리에 의하여 완전히 소실되었다. Protein kinase C 활성화제인 $4{\beta}-phorbol$ 12, 13-dibutyrate (PDB, $1{\sim}10\;{\mu}M$)는 ACh 유리 증가를 일으켰으며 억제제인 polymyxin B (PMB, $0.03{\sim}1\;mg$)는 감소를 일으켰으나, adenosine에 의한 ACh 유리 감소효과는 PDB 및 PMB에 의해 영향을 받지 않았다. $Ca^{++}$-통로 차단제인 nifedipine $(1\;{\mu}M)$은 adenosine의 효과를 길항함을 볼 수 있었으나 $K{^+}$-통로 차단제인 glibenclamide는 adenosine의 효과에 영향을 미치지 못하였다. 8-Bromo-cAMP (100과 $300{\mu}M$) 그 자체로는 ACh 유리에 별다른 영향을 미치치 못하였으나 $300\;{\mu}M$ 8-bromo-cAMP 전처리에 의하여 $30\;{\mu}M\;adenosine$의 효과가 억제됨을 볼 수 있었다. 이상의 실험결과로 흰쥐 해마에서 $A_1-adenosine$ 수용체를 통한 adenosine의 ACh유리 감소는 G-단백에 의존적이며, 이러한 효과에 nifedipine에 예민한 $Ca^{++}$-통로와 adenylate cyclase계가 일부 관여함은 확실하나 proteinkinase C 및 glibenclamide에 예민한 $K{^+}$통로는 관여하지 않는 것으로 사료된다.

• 한국양식학회지
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• 제8권3호
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• pp.171-181
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• 1995

붕어의 년 생식주기를 밝히기 위해 1993년 2월부터 1994년 10월까지 gonadosomatic index (GSI)를 조사하였다. GSI는 4월부터 7월까지는 높은 수준을 나타내며 개체간에 편차가 큰 것으로 보아 이 기간이 산란기임을 보여준다. 8월부터 9월까지는 년중에서 가장 낮은 수준이며 이때 난소내 여포는 퇴화가 진행 중이었다 10월부터 GSI 값은 증가하여 이듬해 3월에 최대치를 보였다. Human chorionic gonadotropin (HCG 10 lU), $17\alpha$, 20\beta-dihydroxyprogesterone\;(1-100{\mu}g/ml)$ 및 phorbol 12-myristate 13-acetate (TPA, protein kinase C activator, 0.1-10${\mu}M$)는 인공배양 시 난모세포의 성숙을 유도하였으나 $4\alpha-phorbol$ 12, 13-didicanoate ($4\alpha-PDD$, phorbol ester analogue, $(25{\mu}M$)는 성숙을 일으키지 않았다. 또한, HCG (10 IU), prostaglandin $F_{2\alpha}$ (0.1-10${\mu}g/ml$) 및 TPA (0.1-10${\mu}M$)는 난모세포의 배란을 유도하였으나 $4\alpha-PDD$$(25\;{\mu}M)$에 의해서는 배란이 일어나지 않았다. 여포세포의 $17\alpha-hydroxyprogesterone$은 HCG (1 IU, 10 IU) 및 forskolin (adenylate cyclase activator, 0.1-10 ${\mu}M$)에 의해 생성이 촉진되었으며 HCG (10 IU) 및 forskolin $(10 {\mu}M)$에 의한 time course 는 3시간 내에 생성량이 증가하여 시간경과에 따른 유의한 차이는 보이지 않았다. 이러한 결과를 종합하면 cyclic AMP와 protein kinase C 는 어류의 난모세포의 성숙과 배란과정에 매우 중요한 역할을 담당하는 것으로 생각된다.

• 대한약리학회지
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• 제32권1호
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• pp.1-11
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• 1996

흰쥐 해마(hippocampus)에서 norepinephrine(NE) 유리에 미치는 $A_1-adenosine$ 수용체의 post-receptor 기전에 관한 지견을 얻고자 하여 $^3H-norepinephrine$으로 평형시킨 해마 절편을 사용하여 adenosine의 $^3H-NE$ 유리에 미치는 여러가지 약물의 영향을 관찰하였다. Adenosine($1{\sim}30{\mu}M$)은 전기자극(3 Hz, 2 ms, 5 Vcm-1, 구형파)에 의한 NE 유리를 용량 의존적으로 감소시켰고, 이 효과는 선택적인 $A_1-adenosine$ 수용체 차단제인 $8-cyclopentyl-1,3-dipropylxanthine(2{\mu}M)$에 의해 차단되었다. G-단백 억제제인 N-ethylmaleimide(NEM, 10과 $30{\mu}M$)는 그 자체로써 전기자극으로 유발시킨 NE 유리를 증가시켰으며, adenosine의 NE 유리 억제효과는 NEM 전처리에 의하여 완전히 소실되었다. Protein kinase C 활성화제인 $4{\beta}-phorbol$ 12,13-dibutyrate(PDB, $1{\mu}M$)는 NE 유리 증가를 일으켰고, 이 효소 억제제인 $4{\beta}-polymyxin$ B(PMB, 0.1 mg)는 NE 유리감소를 일으켰으며, adenosine에 의한 NE 유리 감소효과는 PDB에 의해 억제되었고, PMB 전처리하에서는 감소효과가 출현하지 않았다. $Ca^{2+}$-통로 차단제인 $nifedipine(1{\mu}M$)은 adenosine의 NE 유리 억제효과에 영향을 미치지 못하고, ATP에 의존적인 $K^+-$통로 차단제인 glibenclamide역시 adenosine의 NE 유리 억제효과에 영향을 미치지 못하였다. 그러나 delayed rectifier $K^+-$통로 차단제인 tetraethylammonium(TEA, 3 mM)은 그 자체로 NE 유리를 증가 시켰으며, adenosine의 NE 유리 억제효과를 차단함을 볼 수 있었다. 8-bromo-cAMP(100과 $300{\mu}M$) 그 자체로는 NE 유리에 별다른 영향을 미치지 못하였으나 8-bromo-cAMP 전처리에 의하여 adenosine의 NE 유리 억제효과가 억제됨을 볼 수 있었다. 이상의 실험결과로 흰쥐 해마에서 $A_1-adenosine$ 수용체를 통한 adenosine의 NE 유리 감소는 G-단백에 의존적이며, 이러한 효과에 protein kinase C, TEA에 예민한 $K^+-$통로 및 adenylate cyclase계가 복합적으로 관여하고 nifedipine에 예민한 $Ca^{2+}-$통로와 glibenclamide에 예민한 $K^+-$통로는 관여하지 않는 것으로 사료된다.

• 대한수의학회지
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• 제38권4호
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• pp.712-719
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• 1998

Thyroid function is mainly regulated through cAMP and phophatidylinositol, and it is well known that TSH-stimulated thyroxine ($T_4$) release is inhibited by catecholamine from mouse thyroids via the ${\alpha}_1$-adrenoceptor stimulation. Previous study has established that the inhibition of $T_4$ release by ${\alpha}_1$-adrenoceptor stimulation results in activated protein kinase C (PKC). The purpose of this study was to determine if ion transport systems are involved in the inhibition of $T_4$ release elicited by ${\alpha}_1$-adrenergic agonist in mouse thyroids. TSH-, IBMX- and cAMP analogue-stimulated $T_4$ release were significantly inhibited by methoxamine, R59022 (diacylglycerol kinase inhibitor), and MDL (adenylate cyclase inhibitor). TSH-stimulated $T_4$ release could be inhibited by Bay K 8644 and cyclopiazoic acid, but not by verapamil and tetrodotoxin. The addition of nifedipine ($Ca^{2+}$ channel blocker), tetrodotoxin and lidocaine ($Na^+$ channel blockers), but not amiloride (EIPA) and ryanodine, completely blocked the inhibitory effects of methoxamine on $T_4$ release. TSH-stimulated $T_4$ release was also inhibited by benzamil ($Na^+-Ca^{2+}$ exchange inhibitor). TSH-, IBMX- and cAMP-stimulated $T_4$ release were inhibited by methoxamine or R59022, these effects were reversed by nifedipine. but not by verapamil. Furthermore, nifedipine reversed the inhibitory effects of benzamil and R59022 on TSH-stimulated $T_4$ release. These data suggest that the observed ${\alpha}_1$-adrenoceptor-mediated inhibition of $T_4$ release in mouse thyroids is the result of an increase in intracellular $Na^+$ or $Ca^{2+}$ effected via activation of fast $Na^+$ or nifedipine-sensitive $Ca^{2+}$ channels, and that $Na^+-Ca^{2+}$ exchange may play an important role in reducing thyroid hormone by increasing intracellular $Ca^{2+}$.

• 대한약리학회지
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• 제30권2호
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• pp.243-254
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• 1994

Inflammatory diseases, allergic and asthmatic disorders are caused by the mediator release from the activation of the phospholipase C (PLC), phospholipase D (PLD), methyltransferase or adenylate cyclase etc. during IgG or IgE cross-linking of high affinity receptors on mast cells or basophil surface. One important enzyme activated after IgG or IgE receptor cross-linking is PLD, the enzyme which converts phosphatidylcholine (PC) to phosphatidic acid (PA). Under the hypothesis that these may be some differences in mediator release according to the difference in PLD activity, we attempted to confirm the ginseng saponin effects on the PLD activity. We examined the PLD activity during the passively sensitized mast cell activation in the presence of single component of ginsenosides $(Rc,\;Rg_1,\;Rg_2,\;Rg_3)$. We also measured the amount of mediators (histamine and leukotrienes) released by stimulating with ovalbumin (OA) or calcium ionophore (CaI), Guinea Pig lung mast cells were purified using enzyme digestion, count current elutriation, and discontinuous Percoll density gradient. In purified mast cells prelabeled with $[^3H]$ arachidonic acid or $[^3H]$ palmitic acid, PLD activity was assessed more directly by the production of labeled PEt by PLD-mediated transphosphatidylation in the presence of ethanol. Histanine release was determined by Spectrophotofluorometry, and leukotrienes by radioimmunoassay. The PLD activity during the passively sensitized mast cell activation is increased up to $3{\sim}5times$. The PLD activity during the passively sensitized mast cell activation in the presence of all ginsenosides is decreased up to $4{\sim}11$ times. $Rg_l\;and\;Rg_2$ ginsenoside pretreatment decreased histamine and leukotrienes by 50% in the OA-induced or by 40% in the Cal-induced mast cell after passively sensitization. Rc pretreatment poorly decreased histamine but leukotrienes decreased by 70% in the OA-induced or by 35% in the Cal-induced mast cell. $Rg_3$ ginsenoside pretreatment increased histamine release without challenging OA or Cal but leukotrienes decreased. These observations indicate that single unit of ginsenosldes may be an important contributor to inhibit the release of histamine and leukotrienes in the guinea pig lung mast cells, that inhibits the PLD-mediated formation of DAG evoked by mast cell activation.