Radioimmunoassay of Calcitonin in the Plasma of Rhesus Monkey

We describe a radioimmunoassay for rhesus monkey and human immunoreactive calcitonin, in which a selected goat anti-human calcitonin antiserum, 131l-labeled synthetic human calcitonin tracer, and purified synthetic human calcitonin standards were used. The mean basal con-centration of calcitonin in normal monkey plasma (254 tg/Iiter) was not significantly different from that in normal human plasma (217 tg/Iiter). The data indicate that the method is sensitive (lower limit of detection, 5 ng/liter), specific, accurate, and reproducible (coefficient of vari-ation, 1-11 % over a wide range of concentrations). Monkey calcitonin response to changes in plasma calcium concentration is similar to that in man, with significant correlation between calcium and calcitonin concentrations. Use of this radioimmunoassay for monkey and huma