TY - JOUR
T1 - The suitability of iodinated Angiotensin-(1-7) peptides as pharmacological tools
AU - Loot, Annemarieke E.
AU - Van Buiten, Azuwerus
AU - Roks, Anton J.M.
AU - Henning, Robert H.
PY - 2005
Y1 - 2005
N2 - Introduction: The heptapeptide Angiotensin-(1-7) [(Ang-(1-7)] is a biologically active component of the Renin-Angiotensin System. Pharmacological studies often involve Ang-(1-7) radioactively labelled with 125I. Given the small size of the original peptide, we investigated whether introduction of a rather bulky iodine label interferes with the biological activity of Ang-(1-7). Methods: Ang-(1-7) was labelled with nonradioactive iodine with the chloramine-T method. The reaction products were separated on HPLC and analysed with mass spectrometry. The products were tested for biological activity in two ways: The ability of labelled Ang-(1-7) to block Ang II-induced contraction in rat aortic rings was tested in an organ bath setup. The affinity of labelled angiotensin for ACE in rat plasma was examined in vitro. Results: Iodination of Angiotensin-(1-7) resulted in two main products: monoiodinated and diiodinated Ang-(1-7) that could be easily separated on HPLC. In an organ bath experiment, monoiodinated Ang-(1-7) blocked Ang II responses identical to the native compound, whereas diiodinated Ang-(1-7) had lost its ability to block Ang II responses. Likewise, monoiodinated Ang-(1-7) had retained its affinity for ACE, while the affinity of diiodinated Ang-(1-7) was greatly reduced. Discussion: Monoiodinated Ang-(1-7) has a biological activity identical to the native compound, whereas this is lost in diiodinated Ang-(1-7). Therefore, only the monoiodinated radioactive form seems suited for pharmacological studies.
AB - Introduction: The heptapeptide Angiotensin-(1-7) [(Ang-(1-7)] is a biologically active component of the Renin-Angiotensin System. Pharmacological studies often involve Ang-(1-7) radioactively labelled with 125I. Given the small size of the original peptide, we investigated whether introduction of a rather bulky iodine label interferes with the biological activity of Ang-(1-7). Methods: Ang-(1-7) was labelled with nonradioactive iodine with the chloramine-T method. The reaction products were separated on HPLC and analysed with mass spectrometry. The products were tested for biological activity in two ways: The ability of labelled Ang-(1-7) to block Ang II-induced contraction in rat aortic rings was tested in an organ bath setup. The affinity of labelled angiotensin for ACE in rat plasma was examined in vitro. Results: Iodination of Angiotensin-(1-7) resulted in two main products: monoiodinated and diiodinated Ang-(1-7) that could be easily separated on HPLC. In an organ bath experiment, monoiodinated Ang-(1-7) blocked Ang II responses identical to the native compound, whereas diiodinated Ang-(1-7) had lost its ability to block Ang II responses. Likewise, monoiodinated Ang-(1-7) had retained its affinity for ACE, while the affinity of diiodinated Ang-(1-7) was greatly reduced. Discussion: Monoiodinated Ang-(1-7) has a biological activity identical to the native compound, whereas this is lost in diiodinated Ang-(1-7). Therefore, only the monoiodinated radioactive form seems suited for pharmacological studies.
UR - https://www.scopus.com/pages/publications/21644434339
U2 - 10.1016/j.vascn.2004.07.005
DO - 10.1016/j.vascn.2004.07.005
M3 - Article
C2 - 15596114
AN - SCOPUS:21644434339
SN - 1056-8719
VL - 51
SP - 51
EP - 55
JO - Journal of Pharmacological and Toxicological Methods
JF - Journal of Pharmacological and Toxicological Methods
IS - 1
ER -