| Project/Area Number |
02671107
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | Jichi Medical School |
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Principal Investigator |
IWAMOTO Yasuhiko Associate Professor, Division of Endocrinology and Metabolism, Jichi Medical School, 医学部, 助教授 (60143434)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAISHI Ikuo Division of Endocrinology and Metabolism, Jichi Medical School, 医学部, 助手 (10235731)
KUMAKURA Shinobu Division of Endocrinology and Metabolism, Jichi Medical School, 医学部, 助手 (50186467)
KUZUYA Takeshi Professor, Division of Endocrinology and Metabolism Jichi Medical School, 医学部, 教授 (80048959)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Proinsulin Secretion / Proinsulin / insulin Ratio / Pancreatic B cell Function / NIDDM / Borderline Glucose Intolerance (IGT) / Family History of Diabetes Mellitus / Oral Hypoglycemic Agent / 糖尿病発症因子 / 膵β細胞機能 / インスリン非依在性糖尿病 / 糖負荷試験 境昇型 / 肥満 |
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| Research Abstract |
Previously we reported the disproportionate elevation of serum proinsulin (PI)/insulin (I) ratio in patients with diabetes mellitus, and PI/I ratio seems to be one of clinical indicators of the functional state of the pancreatic B cells. In this study, in order to investigate the effects of several diabetogenic factors on proinsulin secretion, we measured serum proinsulin both at fasting and after oral glucose load in obese subjects with various glucose tolerance, in aged subjects with normal glucose tolerance, and in the borderline glucose intolerant subjects with and without family history of diabetes mellitus. In addition, we studied the effect of sulfonylurea therapy on proinsulin secretion in NIDDM patients.
1. In obese subjects both insulin and proinsulin are elevated and the PI/I ratio remained unchanged, suggesting that each B cell seems to function normally in obese subjects.
2. There was no significant difference in serum PI/I ratio between those with and without family history of diabetes mellitus.
3. Proinsulin secretion is disproportionately increased in aged subjects as compared to that in young subjects, suggesting the functional abnormality of the pancreatic B cells in aged subjects.
4. Disproportionate elevation of proinsulin in borderline glucose intolerance was more marked in low insulin responders (insulinogenic index 0.4). In combination with the previous reports that low insulin responders are known at higher risk to develop diabetes, the elevation of PI/I may provide an additional marker to predict the risk of development of NIDDM.
5. After improvement of glycemic control by sulfonylurea therapy, the elevation of serum PI/I ratio in NIDDM patients could be reduced, suggesting that the relative hypersecretion of proinsulin is a reversible change rather than an irreversible change.
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