Elsevier

Peptides

Volume 12, Issue 5, September–October 1991, Pages 1135-1141
Peptides

Article
Reassessment of plasma angiotensins measurement: Effects of protease inhibitors and sample handling procedures

https://doi.org/10.1016/0196-9781(91)90070-6Get rights and content

Abstract

Characterization of C- and N-terminal forms of angiotensin (Ang) peptides mandated assessment of methods to determine plasma levels. 125I-Ang I, 125I-Ang II, and 125I-Ang(1–7) were added to blood samples in the presence of protease inhibitors. Ethylenediaminetetraacetic acid (EDTA) inhibited the conversion of 125I-Ang I to 125I-Ang II. o-Phenanthroline and EDTA (EDTA + o-Ph) did not eliminate [des-Asp1] fragments or 125I-Ang(1–7). The combination of EDTA + o-Ph and pepstatin A or 4-(chloromercuri) benzoic acid (PCMB) significantly reduced 125I-Ang(1–7) generation. Only PCMB plus EDTA + o-Ph eliminated [des-Asp1] fragments. Authentic plasma values of Ang peptides require the correct choice of protease inhibitors.

References (33)

  • T. Ayoyagi et al.

    Enzyme inhibitors in relation to cancer therapy

    J. Antibiot.

    (1977)
  • H.H. Bausback et al.

    Degradation of low-molecular-weight opioids by vascular plasma membrane aminopeptidase M

    Biochem. Biophys. Acta

    (1982)
  • D. Campbell et al.

    Simultaneous radioimmunoassay of six angiotensin peptides in arterial and venous plasma of man

    J. Hypertens.

    (1990)
  • T. Chiu et al.

    Soluble metalloendopeptidase from rat brain action of enkephalin-containing peptides and other bioactive peptides

    Endocrinology

    (1985)
  • D.J. Daly et al.

    Proline endopeptidase in human muscle

    Biochem. Soc. Transact.

    (1985)
  • R.J. Delenge et al.

    Leucine aminopeptidase and other N-terminal exopeptidases

  • Cited by (82)

    • Newly developed radioimmunoassay for Human Angiotensin-(1–12) measurements in plasma and urine

      2021, Molecular and Cellular Endocrinology
      Citation Excerpt :

      Furthermore, the anti-Ang-(1–12) antibody does not cross-react with any closely related angiotensin peptides [Ang I, Ang-(1–9), Ang II and Ang-(1–7)] at endogenous concentrations reported in human plasma and urine (Lijnen et al., 1978; Cohall et al., 2015; Katsurada et al., 2007; Kobori et al., 2009; Saito et al., 2009; Juretzko et al., 2017). Using this polyclonal antibody, the assay conditions for Ang-(1–12) measurements were identified in individual blood samples drawn from five adult volunteers (3 males and 2 females, age range 20–55 years) and collected with and without a previously reported inhibitor cocktail (Brosnihan and Chappell, 2017; Kohara et al., 1991; Chappell, 2016a). Similarly, collected spot urine samples were processed in the presence and absence of HCl (described in Methods section).

    • Interference by o-phenanthroline in the radioimmunoassay of angiotensin II in small volume blood samples

      2012, Clinical Biochemistry
      Citation Excerpt :

      Extracted buffer samples had slightly higher concentrations than non extracted buffer samples (Table 1), presumably due to higher concentrations of o-phenanthroline in the extract. Previous studies investigating the effects of o-phenanthroline on measurement of Ang II commonly used radioactive Ang II to look at its degradation profile [5,6]. Whereas those studies were capable of detecting direct effects of o-phenanthroline on degradation of Ang II, they would not detect interference by this compound in the assay.

    View all citing articles on Scopus
    View full text