Isolation of parathyroid hormone after extraction with phenol.

In 1925, Collip (1) reported that an endocrine substance, extracted from parathyroid tissue with hot hydrochloric acid, corrected the hypocalcemia which followed parathyroidectomy. Extracts made by this method had been important in early biological studies, but have been difficult to purify, and have seemed to contain several active, but unstable components (2,3). Lately other solvents have been used in an effort to obtain the active principle in more homogeneous form. A potent fraction has been prepared with weak acid in the cold (4), but simple aqueous solutions generally have been poor extractants. Rasmussen (5,6) has obtained highly purified, although incompletely stable material from extracts made with hot 80% acetic acid, a solvent advanced for this purpose by Davies and Gordon (7). Strong phenol solutions have been used to extract a more stable, uniform substance in high yield (8). The product obtained by this means was easily purified to a form suitable for further chemical and biological studies, and its isolation is described herein.