| Project/Area Number |
61571048
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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 |
Biological pharmacy
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| Research Institution | Kyoto University |
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Principal Investigator |
INUI Ken-ichi Kyoto Univ., Faculty of Med., Associate Professor, 医学部, 助教授 (70034030)
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| Co-Investigator(Kenkyū-buntansha) |
KAMIYA Akira Kyoto Univ., Faculty of Med., Lecturer, 医学部, 講師 (90124792)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1987: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Atrial Natriuretic Polypeptide (ANP) / Vasopressin / Receptor Binding / Cyclic GMP / Renal Plasma Membranes / Cultured Renal Epithelial Cell / 腎臓 / ペプチドホルモン受容体 / 利尿作用 / 尿細管上皮細胞 |
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| Research Abstract |
Although atrial natriuretic polypeptide (ANP) possesses potent natriuretic and diuretic activities, in addition to vasorelaxant activity, the site of action and molecular mechanisms by which ANP elicites natriuresis remain unknown. To investigate the localization of ANP receptors and their regulation mechanisms in the kidney, we examined receptor binding and cGMP response by ANP using renal plasma membranes and kidney epithelial cell line (LLC-PK_1).
1. The binding of ^<125>I-<alpha>-human(h)ANP to renal plasma membranes suggested that specific receptors for <alpha>-hANP were localized on basolateral membranes of the renal cortex.
2. The LLC-PK_1 cells retained specific receptors for ANP and responded to <alpha>-hANP by stimulating cyclic GMP formation.
3. The binding of <alpha>-hANP to basolateral membranes from spontaneously hyper-tensive rats (SHR) and stroke-prone SHR (SHR-SP) was measured, and compared with that of Wistar-Kyoto rats (WKY). The apparent dissociation constant and the maximal binding capacity in SHR and SHR-SP were decreased in comparison with those in WKY.
4. The effects of<beta> -hANP, an antiparallel dimer of <alpha>-hANP, on receptor binding and cGMP formation in the LLC-PK_1 cells were studied. Time course of cGMP formation by <beta>-hANP was slow onset and long action compared with that by <alpha>-hANP. High performance gel permeation chromatography coupled with radio-immunoassay for <alpha>-hANP revealed that <beta>-hANP incubated with the cells was converted into a small peptide corresponing to <alpha>-hANP.
5.[Arg^8]Vasopressin inhibited dose-dependently the <slpha>-hANP-stimulated cGMP formation in the absence of 3-isobutyl-1-methylxanthine (IBMX), but not in the presence of IBMX. The inhibitory effect of vasopressin could be regulated via V_1 receptor.
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