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PubMed · 9582104

Decrease in circulating and urine adrenomedullin concentrations in stroke-prone spontaneously hypertensive rats.

S Hirano·Y Ishiyama·T Matsuo·T Imamura·J Sakata·K Kitamura·Y Koiwaya·T Eto
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Abstract

Adrenomedullin (AM) is a peptide with potent vasodilatory and hypotensive properties. Plasma AM levels in rats with experimentally induced hypertension, such as Dahl salt-sensitive rats and two-kidney, one-clip hypertensive rats, are higher than those in normotensive rats. We previously noted, however, that plasma AM levels in spontaneously hypertensive rats (SHR) are similar to those in Wistar-Kyoto rats. To define the role of AM in rats with severe hypertension, we investigated changes in circulating and tissue AM levels in stroke-prone spontaneously hypertensive rats (SHRSP/Izm). The immunoreactive rat AM levels in plasma, urine, and tissue measured with a sensitive radioimmunoassay, and the AM mRNA levels in various tissues in 15-wk-old SHRSP/Izm were compared with those in age-matched Wistar-Kyoto rats (WKY/Izm). The plasma and urinary AM levels in SHRSP/Izm were significantly lower than those in WKY/Izm [plasma AM, 2.14+/-0.06 (SE) vs. 3.24+/-0.16 fmol/ml, p< 0.001; urinary AM, 16.36+/-3.21 vs. 36.12+/-6.09 fmol/ml, p< 0.01]. A negative correlation was found between the plasma AM level and the systolic blood pressure in both SHRSP/Izm and WKY/Izm. Reverse-phase high-performance liquid chromatography showed that the molecular components of plasma immunoreactive AM in SHRSP/Izm were similar to those in WKY/Izm. Furthermore, tissue AM levels in various organs in SHRSP/Izm were not lower than those in WKY/Izm. In conclusion, low levels of circulating AM may contribute to the maintenance of high blood pressure in 15-wk-old SHRSP/Izm. These low plasma AM levels may be caused by accelerated metabolism of circulating AM in SHRSP/Izm.

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AdrenomedullinAge FactorsAlbuminuriaAnimalsAntihypertensive AgentsBlood PressureBody WeightCerebrovascular DisordersCreatineGene ExpressionHeart RateHypertensionMalePeptidesRNA, MessengerRadioimmunoassayRatsRats, Inbred SHRRats, Inbred WKYJournal Article

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S Hirano, Y Ishiyama, T Matsuo, T Imamura, J Sakata, K Kitamura, Y Koiwaya, T Eto. 1998. Decrease in circulating and urine adrenomedullin concentrations in stroke-prone spontaneously hypertensive rats.. https://doi.org/10.1291/hypres.21.23

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