The Effect of Alkalosis on the Relationship between Serum Calcium and Protexn in Vivo*

In the absence of definite experimental evidence, it has generally been assumed that the symptoms of tetany associated with increases in serum pH are due to a decrease in the concentration of ionic calcium. However, by means of the frog heart method, McLean and Hastings (1) were unable to demonstrate any significant change in calcium ions with change in pH. Because of the relatively narrow pH range in which these investigators worked, and the limited range of sensitivity of the method, no definite conclusions were offered, and the question of the effect of alkalosis on the capacity of protein to bind calcium was left open. It has been abundantly confirmed that the concentrations of total calcium and protein in serum, in the absence of recognizable defects of calcium metabolism, bear a linear relationship to each other. This has been expressed by the regression equation, total Ca = a X total protein + b, in which a and b are constants. Using data accumulated in the literature, McLean and Hastings (1) have demonstrated that the value for the intercept b in this equation is a close approximation of the concentration of ionic calcium as determined by their frog heart method, under normal conditions. On the basis of these considerations, the relationship between total calcium and proteins in the serum of normal animals, and those with marked elevation of serum pH, was studied. It was hoped that by these means some idea would be gained as to the effect of alkalosis on the ability of serum protein to bind calcium