Comparative study of immunoactivity and bioactivity of sodium insulin

The bioactivity of equal doses (by radioimmunoassay) of regular insulin and sodium insulin were measured in six preconditioned female mongrel hound dogs by a previously described bioassay. The hypoglycemic nadir of blood glucose induced by intravenous injection of the drugs was compared with the nadirs induced by a known amount of the international standard insulin. The level of blood glucose was monitored-instantaneously and continuously using a nonthrombogenic continuous glucose-monitoring system. The hypoglycemic effect of subcutaneously injected sodium insulin was compared with the effect of subcutaneously injected regular insulin. The two drugs were injected at 1-2-week intervals to seven dogs. While the bioactivity of intravenously administered sodium insulin was equal to the bioactivity of intravenously administered regular insulin, the hypoglycemic effect of subcutaneously injected sodium insulin differed from the effect of subcutaneously injected regular insulin. The blood glucose nadir after subcutaneous injection of regular insulin occurred 101 +/- 21 min after the injection. The nadir after subcutaneous injection of sodium insulin occurred 163 +/- 33 min after the injection.