Sherwood O D, Rosentreter K R, Birkhimer M L
Endocrinology. 1975 May;96(5):1106-13. doi: 10.1210/endo-96-5-1106.
Tyrosine was incorporated into highly purified porcine relaxin employing the reagent N-carboxy-L-tyrosine anhydride. The resulting polytyrosyl-relaxin contained 1.67 mol of tyrosine per mol of relaxin, retained its original biological activity, and was readily radioiodinated to specific activities ranging from 80 to 100 muCi per mug. High affinity antibodies applicable in final dilutions ranging from 1:50,000 to 1:200,000 were developed in rabbits against unconjugated highly purified porcine relaxin. A double antibody radioimmunoassay for porcine relaxin sufficiently sensitive to routinely measure from 32 to 1000 pg of pig relaxin was developed. Using this radioimmunoassay, peripheral serum concentrations of porcine relaxin were found to be less than 1 ng/ml during early pregnancy. Serum concentrations of porcine relaxin were high during late pregnancy. The mean concentration of porcine relaxin one day before parturition was 38 ng per ml. Within a day following parturition relaxin concentrations fell to a mean concentration of 2.1 ng per ml.
利用试剂N-羧基-L-酪氨酸酐将酪氨酸掺入高度纯化的猪松弛素中。所得的聚酪氨酰松弛素每摩尔松弛素含有1.67摩尔酪氨酸，保留了其原有的生物活性，并且易于进行放射性碘化，比活度范围为每微克80至100微居里。用未结合的高度纯化的猪松弛素在兔中制备了适用于1:50,000至1:200,000最终稀释度的高亲和力抗体。开发了一种对猪松弛素足够敏感的双抗体放射免疫测定法，可常规测量32至1000皮克的猪松弛素。使用这种放射免疫测定法，发现妊娠早期外周血清中猪松弛素的浓度低于1纳克/毫升。妊娠后期猪松弛素的血清浓度较高。分娩前一天猪松弛素的平均浓度为每毫升38纳克。分娩后一天内，松弛素浓度降至平均每毫升2.1纳克的浓度。
