Estimation of Plasma Half-Lives of Vasopressin Analogs from Vasopressor Responses by Curve-Fitting

Summary

Vasopressor responses by rats to graded doses of AVP, dAVP, and AVT were analyzed in an attempt to find a method for estimating plasma half-life from responses. The resulting “curve-fit” method indicated half-lives of 2.6 ± 0.3, 4.0 ± 0.3, and 9.2 ± 1.4 min for AVP, AVT, and dAVP, respectively, after single intravenous injections. The half-lives of two peptides can be compared in one rat the “curve-fit” method. This method can also provide useful information concerning the relative contributions of the plasma half-life, the log dose-response relationship, and other factors, to the duration of the response.