THE INFLUENCE OF GELATIN IN THE ASSAY OF PURIFIED PARATHYROID EXTRACTS

Abstract

Parathyroid extracts purified by solvent distribution appeared to have lost activity when assayed in calcium-depleted, parathyroidectomized rats. The addition of gelatin as a vehicle to these extracts almost completely restored their original potency in a 4-hour test; there was little effect at 8, and none at 24 hours. When gelatin was added to Parathyroid Extract, U.S.P. (Lilly), no increase in potency was observed. The potentiating effect of the vehicle with purified preparations might be explained by delayed absorption from the injection site.