Blunted calcitonin responsiveness in Casr+/- mice. On the left (1A), a logarithmic scatterplot of serum calcitonin versus ionized calcium level in wild type and Casr+/- mice. The straight lines indicate the respective best-fit regression lines; the respective 95% confidence intervals for the fitted lines are also shown, and have been demarcated by double-headed arrows for easier recognition. On the right (1B), a normal plot of mean serum calcitonin (± SE) versus mean ionized calcium (± SE) in wild type and Casr+/- mice. Vertical SE bars correspond to the calcitonin values, and horizontal error bars correspond to ionized calcium values. The peak calcitonin response of wild type and Casr+/- was significantly different for both ionized calcium and calcitonin (p < 0.02). In both graphs, the closed squares indicate wild type values, and the open squares indicate Casr+/- values.