1991 Fiscal Year Final Research Report Summary
Role of Endocrine Systems on Changes of Kidney Function during Aging
| Project/Area Number |
02640581
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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 |
動物形態・分類学
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| Research Institution | Shimane Medical University |
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Principal Investigator |
KOBAYASHI Yuta Shimane Medical University, Dept. Pharmacol., Assistant, 医学部, 助手 (40162028)
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| Co-Investigator(Kenkyū-buntansha) |
HATTORI Keisuke Shimane Medical University, Dept. Pharmacol., Professor, 医学部, 教授 (80112134)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Aging / Water-electrolyte metabolism / Kidney / Calcium Metabolism / Osteoporosis / Atrial Natriuretic peptide / Wister / Tw rats / NOD mice |
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| Research Abstract |
Wistar/Tw strain male rats show polydipsia and polyuria after 16 months of age, while after 20 months of age in female rats. Current studies have suggested that this strain is a model for accelerated aging in water and electrolyte metabolism and kidney function, which are important for the control of homeostasis of animals. In the present study, age-related changes of kidney function and role of endocrine systems on the changes were investigated using this substrain rats.
1. Kidney function during aging was studied and age-related increases of serum phospholipids and triglyceride were observed in female rats. These changes are considered to agree with the changes of serum parameters with dysfunction of kidney in human. 2. No significant change on serum atrial natriuretic peptide(ANP)concentration was observed during aging of this strain. Changes on ANP with the occurrence of diabetes mellitus were studied using non-obese diabetic(NOD)mice, as the diabetes mellitus animals also show poly
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dipsia. Significant reduction of serum ANP concentration and significant enhancement of atrial ANP content were observed. 3. Reduction of serum aldosterone concentration and plasma renin activity(1 to 10 fold)during aging of Wistar/Tw strain was observed. These results may be explained by the reduction of release of renin with the pathological changes of kidney. Increase of serum vasopressin concentration during aging has reported. Thus, changes of serum hormones which related to water and electrolyte metabolism have clarified in this substrain. 4. Furthermore, marked increase(10 fold)of urinary excretion of calcium in 24 hours with aging of female rats was found. 5. Reduction of bone materials in X-ray photograph, significant reductions of dry weight and calcium content in the femur, significant reductions of dry weight and mechanical strength of tail vertebrae were observed. These changes suggest that this female rats may be a model rat for spontaneous osteoporosis. 6. Serum calcitonin concentration showed no significant change.
Further studies are necessary to clarify the mechanism of such changes in calcium metabolism during aging. Less
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