Radioimmunoassay of Antiarrhythmic Peptide and Its application

摘要

To establish a specific and sensitive radioimmunoassay (RIA) for antiarrhythmic peptide (AAP) and study serum AAP levels in normal Sprague-Dawley rats (NR) and spontaneous hypertension rats (SHR), AAP-bovine serum albumin (BSA) conjugate was prepared by ammonium bicarbonate method. The New Zealand rabbits were immunized by administering intradermally the conjugate. Then the rabbit anti-AAP serum was produced and iodinated AAP was made by Bolton-Hunter method. The RIA for serum AAP was set up and serum AAP levels in NR and SHR were determined. The minimal detectable range of the AAP RIA was (0. 45 +- 0.06) μg/L. The affinity constant for antiserum was 1.05 X 10~9 L/mol, and the rate of cross-reactivity with atrial peptide (AP) and human growth hormone (hGH) were 0.12% and 0.20%, respectively. The mean recovery rate of high, medium and low doses was 97.6% , and the mean coefficients of variation for intra-and interbath-assay were (6.43 +- 0.85)% and (9.62 +- 1.04)% , respectively. The mean levels of AAP in NR with different age (3 months, 8 - 10 months and 18 - 20 months) were (1.75 +- 0.13) μg/L, (1.74 +- 0.11) μg/L and (1.79 +- 0.15) μg/L, respectively, while those in SHR with different age (3 months, 8-10 months and 18-20 months) were (2.38 +- 0.35) μg/L, (2.54 +- 0.25) μg/L and (2.83 +- 0.21) μg/L, respectively. The levels of serum AAP showed a positive correlation with blood pressure (r = 0.8667, P<0.05). It was indicated that this AAP RIA had high specificity, high accuracy and good reproducibility. The levels of serum AAP had a close relation with blood pressure.