A new preparation of the parathyroid hormone.

The first successful attempt to obtain more active preparations of the parathyroid hormone than, those described by Collip and Clark (1) was reported by Ross and Wood (2) in 1942. Their method was based upon an extraction of beef parathyroid glands with hot dilute acid, followed by fractionation of the extract with alcohol and then with ammonium sulfate, and adsorption of the active principle onto benzoic acid. They obtained a series of preparations with a “nitrogen potency,” activity in U. S. P. units per mg. of nitrogen, of 200 to 300, 2 to 3 times as active as the best preparations of Collip and Clark. This paper is a report upon another method of securing parathyroid hormone preparations of nitrogen potency 200 to 300 in decidedly greater yields than those achieved by Ross and Wood. The new method has three principal steps: (1) preparation of a dry, relatively fat-free gland powder; (2) extraction of the gland powder with warm dilute hydrochloric acid; (3) fractionation of the cleared extract with acetone. The procedure yields about 10,000 units per 100 gm. of fresh glands, several times the quantities obtained by previous methods. The activity of the preparations was in each instance estimated by their effect on the serum phosphorus of the rat, as described in the foregoing paper (3).