Abstract:
:Plasma and serum of healthy subjects apparently contain a precursor form of renin, or 'prorenin,' which can be activated by the ice-cold temperature at which samples are customarily handled for prolonged periods in laboratories and blood banks. The effect of such prior cryoactivation for 9 days at 4 degrees C is to increase subsequent plasma renin activity (PRA) at 37 degrees C by 108 +/- 16.3% (mean +/- SE) over the nonactivated control value (P less than 0.001). At a lower temperature (-4 degrees C), the cryoactivation effect is considerably greater than at 4 degrees C. Cryoactivation is not obliterated by the prefreezing of plasma, or reduced by inclusion of bacteriostats. Nor is it attributable to any detectable reduction in angiotensinase activity. In rats, cryoactivation at 4 degrees C is much lower than in humans, suggesting a marked species difference either in prorenin concentration or in the rapidity of its spontaneous conversion after blood collection. Trypsin at near optimal concentrations also consistently activates human plasma prorenin, whether at 4, 23, or 37 degrees C indicating that cold is not an essential concomitant of tryptic activation. In excess, the magnitude of which varies among individuals, trypsin at first produces activation and later a decline in PRA, probably due to degradation of the reactants (prorenin, renin, angiotensinogen) and of the initial product (angiotensin I). The identity of angiotensin I in activated and control plasmas can be established by specific radioimmunoassay, and bioassay. Our data indicate that tryptic activation involves little direct production of angiotensin I but rather converts prorenin, thereby enhancing the angiotensin generating capacity of the plasma renin system itself. Tryptic activation in plasma of anaesthetized dogs is lower than in humans, but higher than in conscious or anaesthetized rabbits in whom the effect appears to be slight. In anaesthetized rats there is virtually no tryptic activation, which is in line with the results by cryoactivation. Since the renin--angiotensin systems of dogs, rabbits, and rats have been extensively studied in experimental models of human hypertension, these observed departures from human levels of cryoactivation and tryptic activation of prorenin deserve further investigation.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Osmond DH,Cooper RMdoi
10.1139/y78-125subject
Has Abstractpub_date
1978-10-01 00:00:00pages
792-805issue
5eissn
0008-4212issn
1205-7541journal_volume
56pub_type
杂志文章abstract::Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y04-034
更新日期:2004-05-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
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pub_type: 杂志文章,评审
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更新日期:2015-03-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
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更新日期:2014-10-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-268
更新日期:1985-12-01 00:00:00
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pub_type: 杂志文章
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doi:10.1139/cjpp-2019-0337
更新日期:2020-06-01 00:00:00
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pub_type: 杂志文章,评审
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
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更新日期:1995-10-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
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journal_title:Canadian journal of physiology and pharmacology
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doi:10.1139/y81-082
更新日期:1981-06-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y08-016
更新日期:2008-03-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
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更新日期:2012-09-01 00:00:00
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pub_type: 临床试验,杂志文章
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journal_title:Canadian journal of physiology and pharmacology
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journal_title:Canadian journal of physiology and pharmacology
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更新日期:1999-03-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
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更新日期:1991-02-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
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更新日期:1988-04-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
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更新日期:2010-01-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y92-001
更新日期:1992-01-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-76-12-1087
更新日期:1998-12-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1998-02-01 00:00:00
abstract::It was recently shown that a peptide (hypertensive factor, HF) isolated from erythrocyte hemolysates from spontaneously hypertensive rats induced a prolonged elevation of blood pressure in normotensive rats. In addition, the peptide produced a marked stimulation of the in vitro uptake of lanthanum-resistant calcium by...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y94-103
更新日期:1994-07-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-167
更新日期:1984-08-01 00:00:00
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journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y92-266
更新日期:1992-01-01 00:00:00