| The Separate and Combined Effects of Insulin, Dexamethasone and
Growth Hormone on the OB Gene Expression and Leptin Secretion
from Cultured Human Visceral Adipose Tissue |
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Il Tae Hwang1, Kyung Hee Kim2, Jin Soon Hwang3, Choong Ho Shin4, Sei Won Yang4 |
1Department of Pediatrics, College of Medicine, Hallym University, Seoul, Korea
2Department of Pediatrics, College of Medicine, Ewha Womans University, Seoul, Korea
3Department of Pediatrics, College of Medicine, Ajou University, Seoul, Korea
4Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea |
| 인체의 복강 내 지방조직 배양을 통한 OB 유전자 발현과Leptin 분비에 미치는 인슐린, Dexamethasone과 성장호르몬의 단독 또는 복합적 영향에 관한 연구 |
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황일태1, 김경희2, 황진순3, 신충호4, 양세원4 |
1한림대학교 의과대학 소아과학교실
2이화여자대학교 의과대학 소아과학교실
3아주대학교 의과대학 소아과학교실
4서울대학교 의과대학 소아과학교실 |
Correspondence:
Sei Won Yang, Email: growth@snu.ac.kr
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| Abstract |
Purpose
: We investigated the hormonal control of OB gene expression and leptin secretion in cultured human visceral adipose tissue.
Methods
: Visceral adipose tissues were cultured for up to 48 hrs in modified Eagle's medium with varying concentration of hormones : Control(no hormone), bovine insulin(100 nM), Dexamethasone(DEX, 100 nM), growth hormone(GH, 40 ng/mL), insulin＋DEX(100 nM each), insulin＋DEX＋GH(100 nM insulin and DEX, 40 ng/mL GH). Quantitative analysis of leptin mRNA was performed by competitive reverse transcription polymerase chain reaction, and leptin secretion in culture medium was measured by IRMA using a commercial kit.
Results
: The addition of dexamethasone to the medium significantly increased OB gene expression and leptin secretion(P<0.05). Unlike dexamethasone, insulin did not affect OB gene expression and leptin secretion. Both insulin and dexamethasone, at high concentration, significantly stimulated leptin secretion compared with basal values(P<0.05). Leptin gene expression was not significantly increased by GH treatment alone, however GH, in combination with high concentrations of insulin and dexamethasone, attenuated the stimulatory effects of high concentrations of insulin and dexamethasone.
Conclusion
: Insulin cannot increase leptin secretion without the presence of dexamethasone. The mechanism suggested is that insulin may increase leptin secretion in cytoplasm only after dexamethasone increases the expression of OB gene. Further studies are necessary to elucidate the mechanism of the action of insulin on leptin secretion after increasing OB gene expression by dexamethasone. |
| Key Words:
OB gene, Leptin secretion, Fat tissue culture |
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