CHANGES IN THE CHEMICAL AND PHYSICAL CHARACTERISTICS OF THE BLOOD FOLLOWING THE ADMINISTRATION OF PARATHYROID HORMONE

Abstract

A substance present in the parathyroid gland has been proved to increase effectively the amount of calcium in the circulating blood. The substance was first satisfactorily extracted by Collip¹ and his results have since been confirmed by Hjort,² Berman³ and others. This has led to a more definite understanding of certain features in calcium metabolism about which previously there was considerable doubt. There is much speculation as to the condition in which calcium exists in the blood and the factors that operate to maintain or to modify its normal concentration. According to Howland,⁴ calcium, phosphoric acid and carbon dioxide are present in the blood in a finely balanced equilibrium, illustrated by the following equation: As Wells⁵ states, the calcium salts are held partly in solution, partly in protein suspension, and partly in the form of calcium ion protein compounds. This condition is extremely unstable, subject to alteration by very slight