PT - JOURNAL ARTICLE AU - WILLIAM E. HAGEMAN AU - KLAUS HOFMANN AU - ROBERT J. ERTEL AU - JOSEPH P. BUCKLEY TI - SOME ASPECTS OF THE PHARMACOLOGY OF VALYL<sup>5</sup>-β-(PYRAZOLYL-3)-L-ALANYL<sup>6</sup>-ANGIOTENSIN II DP - 1969 Aug 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 295--302 VI - 168 IP - 2 4099 - http://jpet.aspetjournals.org/content/168/2/295.short 4100 - http://jpet.aspetjournals.org/content/168/2/295.full SO - J Pharmacol Exp Ther1969 Aug 01; 168 AB - Several pharmacologic actions of valyl6-β-(pynazolyl-3)-L-alanyl6-angiotensin II (Val5-Pyr(3) Ala6-angiotensin II) were investigated and compared to those produced by Val5-angiotensin II. The Pyr(3) Ala6 derivative possessed 53.4% of the pressor activity of Val5-angiotensin II in the pithed rat and 52.9 to 55.7% in the anesthetized dog. The Pyr(3) Ala6 analog caused an increase in the tension developed by the isolated guinea-pig ileum preparation. Log dose-response curves were linear and parallel, and the analog possessed 23.8% of the intestinal stimulating activity of Va15angiotensin II. The peptide was capable of producing a centrally mediated pressor response which was 48% that of Val5-angiotensin II. Val5-Pyr(3) Ala6-angiotensin II also produced an elevation of the aldostenone output from the adrenal glands of dogs which was less than that produced by Val5-angiotensin II. The results of this investigation suggest that, although the degree of ionization of the imidazole ring may not be a requirement for biologic activity, this ring structure may be necessary for activation of receptors. © 1969 by The Williams &amp; Wilkins Co.