1990 Fiscal Year Final Research Report Summary
Studies on the Causes of Hyponatremia Associated with Adrenal Insufficiency
| Project/Area Number |
63570519
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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 | Tohoku University |
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Principal Investigator |
MURAKAMI Osamu Tohoku Univ. Sch. of Med, 2nd Dept Int Med, Assistant, 医学部, 助手 (00157744)
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| Co-Investigator(Kenkyū-buntansha) |
MOURI Toraichi Tohoku Univ. Sch. of Med, 2nd Dept Int Med, Assistant, 医学部附属病院, 助手 (80004688)
TOTUNE Kazuhito Tohoku Univ. Sch. of Med, 2nd Dept Int Med, Assistant, 医学部附属病院, 助手 (10217515)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Hypothalamus / Paraventricular nucleus / Arginine vasopressin / Corticotropin-releasing hormone / Adrenal insufficiency / Insulin-induced hypoglycemia / Radioimmunoassay / Immunocytochemistry |
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| Research Abstract |
1. Arginine vasopressin (AVP) and corticotropin-releasing hormone (CRH) in the paraventricular nucleus (PVN) of hypothalamus of adrenalectomized rats. AVP and CRH immunostainings in the parvocellular cells of the PVN were increased by adrenalectomy and suppressed by the supplementation of dexamethasone. Aldosterone administration and dehydration had no effects. These findings suggest that the production of AVP in the parvocellular cells of PVN is increased in adrenal insufficiency and this is caused not by mineralocorticoid deficiency or dehydration, but by glucocorticoid deficiency.
2. Co-existence of AVP and CRH in the PVN and CRH immunoreactive nerve fibers in the human hypothalamus. AVP co-exists with CRH in the parvocellular cells of the PVN in human hypothalamuus. CRH-immunoreactive nerve fibers run laterally and downward from the PVN, and then medially toward the pituitary stalk.
3. Novel neuropeptides in human and/or rat hypothalamus. High concentrations of immunoreactive calcito
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nin-gene related peptide (CGRP), brain natriuretic peptide, melanin concentrating hormone (MCH) and cerebellin were found in the hypothalamus by radioimmunoassay. Immunocytochemical studies using postmortem brain showed that CGRP immunoreactive cells were present in the PVN and supraoptic nucleus, and MCH immunoreactive celles were present around the mammillary body of posterior hypothalamus.
4. Plasma AVP and ACTH in insulin-induced hypoglycemia and the comparison with the effect CRH administration. Plasma ACTH were increased during insulin-induced hypoglycemia in healthy subjects and this increase was about 2.6 times larger than in CRH administration. Plasma AVP were increased during insulin-induced hypoglycemia and this increase was not suppressed by the low plasma osmolarity indused by water load. Therefore, the AVP secretion in hypoglycemia is thought to play an important role in the regulation of hypothalamo-pituitaryadrenal axis.
Conclusion : These studies suggest that AVP which co-exists with CRH in the parvocellular cells of the PVN has an important pathophysiological role in the hyponatremia associated with adrenal insufficiency.
Further studies are reguired to clarify the pathophysiological roles of novel neuropeptides such as CGRP in adrenal insufficiency. Less
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