• BMB Reports
• /
• v.33 no.6
• /
• pp.448-453
• /
• 2000

In yeast the key gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase), is selectively targeted from the cytosol to the lysosome (vacuole) for degradation when glucose starved cells are replenished with glucose. The pathway for glucose induced FBPase degradation is unknown. To identify the receptor-mediated degradation pathway of FBPase, we investigated the presence of the FBPase receptor on the vacuolar membrane by cell fractionation experiments and binding assay using vid mutant (vacuolar import and degradation), which is defective in the glucose-induced degradation of FBPase. FBPase sedimented in the pellets from vid24-1 mutant after centrifugation at $15,000{\times}g$ for 15 min, suggesting that FBPase is associated with subcellular structures. Cell fractionation experiments revealed that FBPase is preferentially associated with the vacuole, but not with other organelles in vid24-1. FBPase enriched fractions that cofractionated with the vacuole were sensitive to proteinase K digestion, indicating that FBPase is peripherally associated with the vacuole. We developed an assay for the binding of FBPase to the vacuole. The assay revealed that FBPase bound to the vacuole with a Kd of $2.3{\times}10^6M$. The binding was saturable and specific. These results suggest that a receptor for FBPase degradation exists on the vacuolar membrane. It implies the existence of the receptor-mediated degradation pathway of FBPase by the lysosome.

• Natural Product Sciences
• /
• v.26 no.4
• /
• pp.345-350
• /
• 2020

In recent years, tyrosine kinases (TKs) have been the target to combat cancers, and most of the developed inhibitors are of synthetic origin. Natural compounds that have the properties as the TK's inhibitors are very limited. This paper described the isolation of a new dammarane triterpene from the tree bark of Sandoricum koetjape, along with three known related dammaranes from the damar resin of Shorea javanica, as well as their inhibitory properties against eight receptor TKs (RTKs: EGFR, HER2, HER4, IGF1R, InsR, KDR, PDGFRα, and PDGFRβ). Based on the NMR and mass spectral data the new compound was identified as (12β,20S)-12,20-dihydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (12β-hydroxydammarenolic acid) (1), while the three known compounds were identified as (20S)-20-hydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (dammarenolic acid) (2), (3β,20S)-3,20-dihydroxydammaran-24-ene (3), and (20S)-3-oxo-20-hydroxydammaran-24-ene (4). The tyrosine kinase assay of the four compounds resulted only 1 and 2 at concentration of 10 μM that had weak activity against EGFR and InsR, with their % inhibitory were 30%, 27% (1), 45%, and 32% (2), respectively. The results suggested that the presence of a linear carboxylic acid group in both compounds could be of significance to the inhibitory properties against the two RTKs.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.2
• /
• pp.137-142
• /
• 2000

The physiological roles of brain angiotensin II in mediating water deprivation-induced drinking and in regulating renal renin release were assessed in male Sprague-Dawley rats. Specific $AT_1$ receptor antagonists, losartan and SK 1080, and antisense oligonucleotide (AS-ODN) directed to $AT_1$ receptor mRNA were intracerebroventricularly (i.c.v.) administered in conscious unrestrained rats. When water was given 20 min after i.c.v. injection of $AT_1$ receptor antagonists in 48-h water-deprived rats, losartan and SK 1080 produced approximatly 20% and 50% decrease in 1-h water intake, respectively. In contrast, i.c.v. treatment of the AS-ODN to $AT_1$ receptor mRNA for 24-h did not alter 1-h water intake in 24-h water-deprived rats, but prevented the increase in overnight water intake after 24-h water-deprivation. Six-day i.c.v. treatment of AS-ODN did not alter either the basal plasma renin concentration or renal cortical levels of renin and renin mRNA. The present results suggest that endogenous brain Ang II plays an important role in thirst and water intake through $AT_1$ receptors, but further studies are required to elucidate its regulatory role in renal renin synthesis.

• Journal of Embryo Transfer
• /
• v.17 no.3
• /
• pp.171-177
• /
• 2002

Glucocorticoid is activating mammary gland cells for lactating animals, resulting in increasing abilities of the milk synthesis. Expression of the prolactin receptor(PRL-R) in mammary gland cells was closely associated with milk production. To increase lactation ability for the Korean Native Goats at mid-lactation period. 0.05, 0.1. and 0.2 g of hydrocortisone was administrated with 5 $m\ell$ of saline. and injected into vein. For the control, 5 $m\ell$ of saline was administrated in to vein. After 24 H, the mammary gland tissue was collected, and mRNA expression rates were investigated for the alpha-casein and PRL-R using competitive PCR(polymerase chain reaction). There was no significant differences between treatment and control groups for the mRNA expression rate of PRL-R in mammary gland cells after 24 h of administration of hydrocortisone. The rate of mRNA expression for the alpha-casein was increased 37%, 630%, and 380% at 0.05, 0.1, and 0.2 g of hydrocortisone administration groups, respectively, comparing with control group. The results suggested that PR L-R mRNA expression of mammary gland cell by administration of hydrocortison was not significant, but increase of the alpha-casein mRNA expression my be differences of expression of functional proteins in the cell and expression patterns of protein secretion time to out of the cell. This study showed increase of alpha-casein mRNA expression by administration of hydrocortisone at mid-lactation period of Korean native goat.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.5
• /
• pp.467-475
• /
• 1997

Although one of the major physiological functions of taurine(2-aminoethanesulfonic acid) is the inhibitory action on the central nervous system(CNS), the mechanism of taurine in controlling the neuronal excitation in the CNS has been in controversy. Electrically evoked pEPSP and spontaneous activity induced by the perfusion of low $Mg^{++}-ACSF$ were recorded in the CA1 pyramidal cell layer of the hippocampal slice. To test the inhibitory effect of taurine on spontaneous responses, taurine was treated for 2 min at various concentrations(1 mM-10 mM). Taurine reduced the spontaneous activity by 22.2% at 1 mM, and 100% at 2 mM in low $Mg^{++}-ACSF$. Evoked response was induced by electrical stimulation of Schaffer collateral-commissural fibers. Taurine reduced the evoked response by 11.68% at 3 mM, and 24.25% at 5 mM. Even 20 mM of taurine reduced the evoked response only by 24 % after 5 min treatment. That is, the inhibitory efficacy was much higher in spontaneous activity than in evoked response. The $GABA_A$ receptor antagonist, 100 uM bicuculline, blocked the inhibitory action of taurine, while $GABA_B$ receptor antagonist, 700 uM phaclofen, did not. Taurine blocked the spontaneous activity in the presence of CNQX, and did not block the electrically evoked responce in the presence of APV. The results suggest that taurine causes hyperpolarization in the cell by binding to $GABA_A$ receptor and preferentially attenuates NMDA receptor-mediated hyperexcitation, leaving synaptic transmission unmodified.

• Archives of Pharmacal Research
• /
• v.27 no.4
• /
• pp.402-406
• /
• 2004

This research team found in previous studies, that the ginseng saponin metabolite IH901 induces apoptosis in HepG2 cells via a mitochondrial-mediated pathway, which resulted in the activation of caspase-9 and subsequently of caspase-3 and -8. Based on these results, the involvement of the Fas/Fas ligand (FasL) death-receptor pathway, in IH901-induced apoptosis in HepG2 cells, was investigated. Levels of Fas and the Fas ligand (FasL) mRNA or protein were not increased by IH901, rather they were decreased significantly at 18 h post treatment. Soluble FasL (sFasL) was detectable by immunoprecipitation analysis En the medium of HepG2 cells treated with IH901. Increased levels of sFasL were inversely correlated with the levels of FasL. Preincubation of HepG2 cells with antagonistic anti-Fas antibody showed little protective effect, if any, on IH901-induced cell death. At a $30{\mu}M$ (24 and 48 h) and $40{\mu}M$ (24 h) concentration of IH901, the cytotoxic effect of IH901 was less then $50\%$, anti-Fas antibody prevented IH901-induced cell death. However, at a $60{\mu}M$ (24 and 48 h) and $40{\mu}M$ (48 h) concentration of IH901, cell death rates were about $80\%$ or more and most of the chemopreventive and chemotherapeutic effects of IH901 were manifested. Blocking the Fas receptor did not influence IH901-induced cell death. These results indicate that the Fas/FasL system is engaged, but not required for IH901-induced cell death, at pharmacologically significant concentrations.

• Development and Reproduction
• /
• v.24 no.4
• /
• pp.287-296
• /
• 2020

The absence of functional estrogen receptor α (Esr1) results in an overgrowth of the epididymal fat, as observed in estrogen receptor α knockout (ERαKO) mouse. The present research was aimed to evaluate expression of various molecules associated with adipocyte differentiation and maturation in the epididymal fat of ERαKO mouse at several postnatal ages by using quantitative real-time polymerase chain reaction. The highest transcript levels of all molecules were detected at 12 months of postnatal age, except leptin which the mRNA level was increased at 5 months of age and was unchanged until 12 months of age. The expression levels of CCAAT enhancer binding protein (Cebp) alpha, androgen receptor, and lipoprotein lipase were decreased at 5 months of age but increased at about 8 months of age. The mRNA levels of Cebp gamma and sterol regulatory element binding transcription factor 1 remained steady until 8 months of age. Continuous increases of transcript levels during postnatal period were found in Cebp beta, estrogen receptor (ER) beta, fatty acid binding protein 4, and delta like non-canonical Notch ligand 1. The increases of peroxisome proliferator-activated receptor gamma and adiponectin mRNA levels were detected as early as 8 months of age. The levels of fatty acid synthase and resistin transcript at 5 and 8 months of age were lower than that at 2 months of age. These findings show the aberrant expression patterns of genes related to adipocyte differentiation and maturation in the postnatal epididymal fat pad by the disruption of ER alpha function.

• Korean Journal of Veterinary Research
• /
• v.24 no.1
• /
• pp.17-23
• /
• 1984

To validate the physiological properties of the histamine receptors of ileal smooth muscle in dog, the effects of adrenergic-, cholineric-, and H-receptor antagonists on the responses of ileal smooth muscle strips to histamine were investigated. The results were summarized as follows; 1. Histamine caused the contraction of ileal smooth muscle and the contractile responses were increased between the concentration of histamine $10^{-7}M$ and $10^{-5}M$ with dose-dependent manner in dog. 2. The shorter the treatment interval of histamine, the lower the contractile activity until the treatment interval extended to 40 minutes. 3. The contractile response induced by histamine was completely blocked by the pre treatment with a $H_1$-receptor blocker, chlorpheniramine and not by the pretreatment with a $H_2$-receptor blockers cimetidine. 4. The contractile response induced by histamine was not blocked by the pretreatment with a cholinergic receptor blocker, atropine. 5. The contractile response induced by histamine was not blocked by the pretreatment with an ${\alpha}$-adrenergic receptor blocker, phenoxybenzamine, or a ${\beta}$-adrenergic receptor blocker, propranolol. From these results, it was suggested that the contraction induced by histamine was elicited through $H_1$-receptor on the ileal smooth muscle in dog.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.1
• /
• pp.31-39
• /
• 1998

As it has been reported that the depolarization induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1$ adenosine heteroreceptor and various lines of evidence suggest the $A_2$ adenosine receptor is present in the hippocampus. The present study was undertaken to delineate the role of adenosine receptors on the hippocampal ACh release. Slices from the rat hippocampus were equilibrated with $[^3H]choline$ and then the release amount of the labelled product, $[^3H]ACh$, which was evoked by electrical stimulation (rectangular pulses, 3 Hz, 2 ms, 24 mA, $5\;V/cm^{-1}$, 2 min), was measured, and the influence of various adenosine receptor-related agents on the evoked tritium outflow was investigated. And also, the drug-receptor binding assay was performed in order to confirm the presence of $A_1$ and $A_2$ adenosine receptors in the rat hippocampus. N-ethylcarboxamidoadenosine (NECA), a potent adenosine receptor agonist with nearly equal affinity at $A_1$ and $A_2$ adenosine receptors, in concentrations ranging from $1{\sim}30\;{\mu}M$, decreased the electrically-evoked $[^3H]ACh$ release in a concentration-dependent manner without affecting the basal rate of release. And the effect of NECA was significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 2 ${\mu}M$), a selective $A_1$ adenosine receptor antagonist, but was not influenced by 3,7-dimethyl-1-propargylxanthine (DMPX, 5 ${\mu}M$), a specific $A_2$ adenosine receptor antagonist. $N^6-cyclopentyladenosine$ (CPA), a selective $A_1$ adenosine receptor agonist, in doses ranging from 0.1 to 10 ${\mu}M$, reduced evoked $[^3H]ACh$ release in a dose-dependent manner without the change of the basal release. And the effect of CPA was significantly inhibited by 2 ${\mu}M$ DPCPX treatment. 2-P-(2-carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS-21680C), a potent $A_2$ adenosine receptor agonist, in concentrations ranging from 0.1 to 10 ${\mu}M$, did not alter the evoked ACh release. In the drug-receptor binding assay, the binding of $[^3H]2-chloro-N^6-cyclopentyladenosine$ ($[^3H]$CCPA) to the $A_1$ adenosine receptor of rat hippocampal membranes was inhibited by CPA ($K_i$ = 1.22 nM), NECA ($K_i=10.17 nM$) and DPCPX ($K_i=161.86 nM$), but not by CGS-21680C ($K_i=2,380 nM$) and DMPX ($K_i=22,367 nM$). However, the specific binding of $[^3H]CGS-21680C$ to the $A_2$ adenosine receptor was not observed. These results suggest that the $A_1$ adenosine heteroreceptor play an important role in evoked ACh release, but the presence of $A_2$ adenosine receptor is not confirmed in this study.

• The Korean Journal of Food And Nutrition
• /
• v.24 no.2
• /
• pp.268-272
• /
• 2011

전곡류의 섭취와 만성질환의 유병율은 음의 상관관계가 있는 것으로 알려져 있다. 본 연구에서는 선행 연구 결과, 지방축적억제능이 우수한 소재로 선정된 기장의 항염증능 여부를 검증하고자 하였다. 이를 위해 RAW264.7 세포에 기장열수분획($1\;{\mu}g/m\ell$ 및 $10\;{\mu}g/m\ell$)과 lipopolysaccharide(LPS)를 함께 처리한 후, 24시간 배양시켜 염증매개인자들의 분비량 및 mRNA 발현 정도를 측정하였다. 또한 LPS 자극에 대한 첫 번째 신호전달인자로 알려져 있는 interleukin-1 receptor associated kinase-4(IRAK-4)의 단백질 발현 정도를 측정하였다. 본 연구결과, 기장의 열수분획($10\;{\mu}g/m\ell$)은 LPS로 유도된 NO, $PGE_2$, TNF-${\alpha}$, IL-6 및 MCP-1의 생성량 및 mRNA 발현량을 유의적으로 억제하였다(p<0.05). 특히 이들 지표 중 pro-inflammatory cytokine인 TNF-${\alpha}$와 IL-6의 mRNA 발현량이 효과적으로 감소하였다(p<0.01). IRAK-4의 단백질 발현량 또한 유의적으로 감소하여 LPS 자극에 대한 기장열수분획의 항염증능은 toll-like receptor(TLR)를 통한 IRAK-4를 매개로 하는 신호전달체계 조절에 기인하는 것으로 사료된다.