2005 Fiscal Year Final Research Report Summary
The isolation and characterization of anti-diabetic humoral factor mediated by leptin in hypothalamus
| Project/Area Number |
16590890
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Metabolomics
|
|---|
| Research Institution | Oita University |
|---|
Principal Investigator |
KAKUMA Tetsuya Oita University, Faculty of Medicine 1, Assis.Prof., 医学部, 助手 (80343359)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YOSHIMATSU Hironobu Oita University, Faculty of Medicine 1, Professor, 医学部, 教授 (00166993)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | Leptin / Streptozotocin induced diabetes / Sympathetic nerve activity / Neuronal histamine / CRH / Ghrelin / UCP |
|---|
| Research Abstract |
In this study we demonstrated that hypoleptinemia, but not hypoinsulinemia, induces hyperphagia and chronic central leptin infusion restores hyperglycemia independent of food intake and insulin level, by regulating hepatic glucose production, peripheral glucose uptake, and energy expenditure in streptozotocin-induced diabetic rats. Leptin may contribute to the improvement of abnormal hyperglycemia in STZ-induced diabetes that presumably is mediated by the sympathetic nervous and/or neuroendocrine systems. The antiobese and antidiabetic actions of CRH signaling and neuronal histamine have been observed in a previous study and our reports. In this study we demonstrated that CRH and histamine neurons are the important mediators for leptin that contribute to regulation of feeding, and adiposity and UCPs expression through sympathetic nervous activation. Ghrelin, a novel gastrointestinal hormone, has been identified in the stomach, is an endogeous ligand for the growth hormone secretagogue receptor, and the peripheral or central administration of ghrelin increases food intake and body weight. Recent research has reported increased levels of stomach and plasma ghrelin in STZ-induced DM rats. In this study we demonstrated that leptin can reverse elevated plasma ghrelin levels independent of insulin concentration and food intake. These results suggest that CRH, neuronal histamine, and ghrelin are characterized for anti-diabetic factors mediated by leptin.
|
