• Journal of Photoscience
• /
• 제9권2호
• /
• pp.94-97
• /
• 2002

Light is one of the most important environmental factors that influence plant growth and development. It does not function independently but exerts its role through coordinated interactions with intrinsic developmental programs, such as hormonal regulation. One typical example is hypocotyl growth in which light signals are modulated through growth hormones. However, the underlying molecular mechanisms are largely unknown. We demonstrated that brassinosteroids play an important role in the light signal transduction in etiolated hypocotyl growth. A light-responsive Ras-like G-protein, Pra2 from pea, physically and functionally interacts with a cytochrome P450 that specifically catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 expression, along with Pra2, is induced in the dark and predominantly localized in the rapidly elongating zone of etiolated pea epicotyls. Transgenic plants with a reduced level of Pra2 exhibit a dark-specific dwarfism, which is completely rescued by brassinosteroid application. On the contrary, overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyl growth. It is therefore envisioned that Pra2 is a molecular switch that mediates the crosstalk between light and brassinosteroids in the etiolation process.

• BMB Reports
• /
• 제44권10호
• /
• pp.613-618
• /
• 2011

Two key molecules in skeletal tissues are bone formation master transcription factor Runx2 and the steroid hormone estrogen. It is well known that these two molecules play pivotal roles in bone homeostasis; however, the functional interaction between Runx2 and estrogen synthesis in skeletal tissues is largely unknown. Recent studies have indicated that there is a positive relationship between Runx2 and the estrogen biosynthesis pathway. In this review, a possible functional link between Runx2 and estrogen synthesis pathway in skeletal tissues will be discusses as well as the biological significance of this interaction.

• Journal of Nutrition and Health
• /
• 제33권4호
• /
• pp.395-402
• /
• 2000

This study was carried out to explore the hypocholesterolemic effect of dehyulled defatty soy flour and its possible mechanisms including endocrine status, cholesterol biosynthesis, and fecal excretion in rats. Animals fed casein were used as control and each phospholipid compared with casein feeding. Cholesterol concentrations in all lipoprotein fraction were significantly lower in defatted soy flour group compared with casein-fed control. Defatted soy flour feeding also significantly lowered hepatic total lipid, cholesteol and TG, and increaed fecal bile acid excretion by 270% compared with casein feeding. Defattd soy flour feeding had no significant effect on plasma thyroid hormone levels and hepatic 3-hydroxy-3-methyl glutary coenzyme A(HMG-CoA) reductase activity. However, plasma T4 concentration was slightly elevated and HMG-CoA reductase activity was suppressed in defatted soy flour group. These metabolic alterations partially explain the reduced plasma and hepatic cholesterol levels of rats fed defatted soy flour.

• Reproductive and Developmental Biology
• /
• 제34권2호
• /
• pp.111-115
• /
• 2010

Erythropoietin (EPO), a glycoprotein hormone produced from primarily cells of the peritubular capillary endothelium of the kidney, is responsible for the regulation of red blood cell production. We have been investigating the roles of glycosylation site added in the biosynthesis and function of recombinant protein. In this study, we analyzed by immunohistochemical methods adaptive mechanisms to excessive erythrocytosis in transgenic (tg) mice expressing dimeric human erythropoietin (dHuEPO) gene. Splenomegaly was observed over 11~21 times in the tg mice. The 2,672 candidate spleen-derived genes were identified through the microarray analysis method, and decreased genes were higher than increased genes in the spleen. The specific proteins in the increased and decreased genes were analyzed by immunohistochemical methods. Our results demonstrate that problems of abnormal splenomegaly would solve in tg mice overexpressing dHuEPO gene.

• Journal of Dairy Science and Biotechnology
• /
• 제36권1호
• /
• pp.26-31
• /
• 2018

Tarak is a traditional Korean fermented milk product, which is prepared by the addition of rice wine to milk. The major microbial strains found in Tarak are Leuconostoc citreum, Lactobacillus plantarum, Lactococcus lactis, Saccharomyces cerevisiae, and Pichia kudriavzevii. The activity of lactic acid bacteria isolated from traditional Korean foods of Taraki against the carcinogenic bacteria Helicobacter pylori, Escherichia coli O157:H7, and Cronobacter sakazakii was characterized. Tarak extract significantly increased the proliferation of T-lymphocyte Jurkat (clone E6-1) cells. Tarak also inhibited the tyrosinase activity and melanin biosynthesis induced by an ${\alpha}$-melanocyte-stimulating hormone in pituitary intermediate lobe.

• Applied Biological Chemistry
• /
• 제19권2호
• /
• pp.70-74
• /
• 1976

Thyroid hormone의 생합성반응기작을 알아보기 위하여 방사선 I-131을 쥐에 주사한 후 thyroid gland을 분리하여 분석하였다. Pancreatin viokase를 처리하여 분리한 요드화합물을 여지 크로마토그라피로 분리 동정하고 이를 radioautography로 분석한 결과 I-131은 주사후 바로 쥐의 체내에서 흡수되어 monoiodotyrosine이 되고 이것은 diiodotyrosine으로 전환됨을 관찰하였다. 실험결과는 diiodotyrosine은 thyroxine 생합성에 있어서 중간생성물이나 반면 triiodothyronine은 오히려 분해산물임을 보여 주었다. 또한 환원제인 propylthiouracil을 투여한 쥐에서 iodine의 체내집적현상(Iodine Pump)은 현저히 증가하였으나 유기 요도화합물을 전환되는 것을 저하였다.

• 생명과학회지
• /
• 제13권3호
• /
• pp.248-251
• /
• 2003

갑상선호르몬의 전구체인 thyroglobulin (Tg)이 어떻게 dimerization이 일어나는지를 조사하였다, 변성 혹은 비변성전기영동법으로 관찰한 결과 새롭게 만들어지기 시작한 Tg는 15분에 처음으로 구조적으로 불안정하지만 folded monomer가 관찰되었다. 그 이후에 monomer가 dimer로 바뀌어 결국 30분에 dimer Tg가 만들어지기 시작하여 40분에는 dimer Tg가 관찰되었다. 최종적으로 60분에 완전하게 dimerization된 Tg가 만들어졌다.

• 대한약리학회지
• /
• 제30권1호
• /
• pp.19-28
• /
• 1994

흰쥐의 뇌하수체 전엽배양세포에 gonadotropin-releasing hormone (GnRH)을 처리하였을 때 시간이 경과함에 따라 GnRH농도에 비례하여 luteinizing hormone(LH)의 분비가 증가하였으며, 2시간까지 급격하게 증가하였다. 또한 GnRH를 처리하였을때 ${\alpha}$ subunit mRNA의 농도는 증가하지 않았으나 $LH{\beta}$ subunit mRNA의 농도는 GnRH 농도에 비례하여 증가하였으며, GnRH 처리후 6시간 이후부터 유의하게 증가하였다. 특히 최종농도가 $2{\times}10^{-10}M$이 되도록 GnRH를 처리하였을 때 $LH{\beta}$ subunit mRNA 농도가 2.7배 정도 최대로 증가하였다. 또한 estradiol을 단독으로 또는 GnRH와 동시에 처리하였을때 LH분비가 증가하지 않았으나 progesterone을 GnRH와 동시에 처리하였을때 LH분비가 유의하게 증가하였다. 또한 $LH{\beta}$ subunit mRNA의 농도는 estradiol및 progesterone을 단독으로 또는 GnRH와 동시에 처리하였을때 난소호르몬 농도에 의존적으로 $LH{\beta}$ subunit mRNA의 농도가 증가하였다. Estradiol에 의한 $LH{\beta}$ subunit mRNA의 증가양상은 estrogen 길항제인 LY117018에 의하여 유의하게 감소하였다. 이러한 결과로 보아 GnRH는 steady state $LH{\beta}$ subunit mRNA 농도에 영향을 미치므로써 LH분비 및 LH subunit 생합성을 조절하며 난소호르몬은 뇌하수체에 직접 작용하여 LH분비 및 LH subunit 생합성에 영향을 주는 것으로 보인다.

• 한국환경성돌연변이발암원학회지
• /
• 제26권2호
• /
• pp.53-58
• /
• 2006

Normally, environmental toxicants are classified as endocrine disruptors if they interfere with regulation of cellular function by endogeneous steroids through inhibition of receptor binding and/or transcriptional activation. So, many studies have been performed about agonist/antagonist of hormone receptor to study mechanisms of endocrine disruptors. If toxicants affect steroid biosynthesis and/or degradation and alter hormone homeostasis, these also are classified as endocrine disruptors. But there are not many studies of the mechanisms of endocrine disruptors on the basis of alteration of steroid biosynthesis and/or degradation. Isolation and culture of Leydig cells from testis is one of methods for the steroidogenesis screening assays to evaluate a substance for altering steroidogenesis. Leydig cells were harvested using the method described by Klinefelter with modifications. Leydig cells were purified by perfusion of testis and incubation ($34^{\circ}C$, 80cycles/minute, 20 minutes) with collagenase (0.25 mg/kg), centrifugal elutriation, percoll gradient centrifugation and BSA multidensity gradient centrifugation. To confirm if this method is one of appropriate tools to evaluate a substance for altering steroidogenesis, ketoconazole, positive control was administered to purified Leydig cells. Ketoconazole ($10^{-8}M$ and above) significantly reduced testosterone production in purified Leydig cells. From above results, we suggest that this method for steroidogenesis screening assay appears to be a appropriate tool to detect suspected compounds for altering steroidogenesis.

• 동의생리병리학회지
• /
• 제21권1호
• /
• pp.50-53
• /
• 2007

To develope skin-whitening or therapeutic agents against hyperpigmentation, aqueous extract from Amomum xanthioides (AEAX) was evaluated for melanogenesis inhibitory activity in B16F10 melanoma cell. The treatment with AEAX at the 0.5 and 1.0 mg/ml level significantly inhibits the biosynthesis of melanin compared with untreated control. The AEAX-treated cells at the 1.0 mg/ml level were more efficient than commercial arbutin at 0.1 mg/ml. The tyrosinase activity also significantly decreased in AEAX-treated cells at the 0.5 and 1.0 mg/ml level. The Western analyses confirmed the significantly decreased expression of tyrosinase and tyrosinase-related protein-1 by AEAX treatment. These results indicate that AEAX may contribute to the inhibition of melanin biosynthesis through regulating tyrosinase activity and expression and serve as a new candidate in the design of new skin-whitening or therapeutic agents.