The hormone of the parathyroid gland.

Abstract

The first stage in the extraction of parathyroid active principle is accomplished by extracting in hot acid, preferably dilute hydrochloric acid. 1

PREPARATION OF THE HYDROCHLORIC X.

Fresh bovine parathyroid glands (freed from fat as much as possible, without removing parts of the gland) finely divided 30 gm.

Pure distilled water 495 cc.

Concentrated hydrochloric acid (C. P.) 5 cc.

This is boiled for two hours, the solution allowed to cool and made up to 500 cc. with pure distilled water. Most of the insoluble fats are removed by the ordinary process of skimming. Some of the fat adheres to the container in the solidified state. Pyrex glassware is used throughout the entire process, using glass ladles for skimming. The solution is filtered through gauze and fine mesh filter-paper. 5 cc. of the Hydrochloric X are equivalent to 0.3 gm. of the fresh gland. If the fresh glands are finely ground in a Latapie grinder, boiling for fifteen minutes is sufficient to bring out the full amount of the active principle obtainable. Boiling for two hours, however, does not lessen its activity.

The Hydrochloric X may be modified as the first step in its purification, by adding sodium hydroxide, preferably in a concentrated solution to avoid too great an increase in its bulk, to the point of maximum precipitation, filtering and concentrating by evaporating in a vacuum.

The injection of amounts of this preparation equivalent to 0.3 gm. of the fresh gland, causes a marked rise in the calcium content of the blood serum of thyroparathyroidectomized dogs, ranging in weight from 9 kg. to 14 kg. In the dogs reported, a rise in the blood serum calcium above the content normal for each dog, or the content found previous to operation, the percentage increase ranged from 27.6 to 80.8; while the per'centage increase above the lower level, following thyroparathyroidectomy, ranged from 82.5 to 136.