TY - JOUR T1 - A METHOD OF STANDARDISING PITUITARY (INFUNDIBULAR) EXTRACTS JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 75 LP - 95 VL - 4 IS - 1 AU - H. H. DALE AU - P. P. LAIDLAW Y1 - 1912/09/01 UR - http://jpet.aspetjournals.org/content/4/1/75.abstract N2 - A method of comparative physiological estimation of the activity of pituitary (infundibular) extracts is described, the test organ being the isolated uterus of the virgin guinea-pig, which, when certain precautions are observed, is found to give a very uniform series of responses to successive equivalent doses. This method is found to detect differences of activity which escape recognition by the blood-pressure test, but appreciable differences of pressor activity always correspond to large differences of action on the uterus in the same direction. The action on the uterus may be adopted, therefore, as a criterion of the general activity of the extract. The method is essentially comparative and not absolute, so that an arbitrary standard must be adopted and renewed at intervals. ER -