THE POSTERIOR PITUITARY-LIKE ACTIVITY OF COMMERCIAL ANTERIOR PITUITARY PREPARATIONS

¹ From the Department of Pharmacology, University of Bristol, England

1. Nine commercial preparations of Anterior Pituitary Extracts and their fractions were investigated for their posterior pituitary activity.

2. The oxytocic, pressor and antidiuretic activities of each preparation were tested. The resistance to 2N sodium hydroxide of any of the posterior pituitary-like factors found was determined.

3. Seven out of the nine preparations were found to contain neligible amounts of posterior pituitary activity. One preparation contained per cc. the equivalent of 40 to 100 mU. of Pituitary (posterior lobe) Extract. The posterior pituitary-like activity of another extract varied considerably from batch to batch, amounting in one case to the equivalent of about 10 units of Pituitary (posterior lobe) Extract per cc.