Abstract

1. Simple aqueous extracts of the posterior and anterior lobes of the pituitary gland prepared in such a way as to abolish their blood-pressure raising properties and to preclude all chance of bacterial activity were found to possess blood-pressure lowering and broncho-constrictor properties.

2. Extracts of this kind made from the posterior lobe of the gland are from seven to eight times more depressant for the arterial pressure than are similar extracts of the anterior lobe, equal weights of the two lobes being used as the basis of comparison.

3. The broncho-constrictor action of extracts of the posterior lobe is very marked in comparison with that exhibited by extracts of the anterior lobe and the ratio of the activity of equivalent extracts of the two lobes is certainly greater than 8 : 1.

4. Chloroform takes up from a properly prepared and dried extract of sterile posterior and anterior lobes of the pituitary gland a determinable amount of a substance which acts like histamine on the arterial pressure, the uterus and the bronchi. The posterior lobe yields to chloroform about twenty times more of this substance than does the anterior lobe, weight for weight of fresh material.

5. The substance which passes into chloroform and which has the pharmacodynamic action of histamine is thought to be this latter compound, because of its behavior during the chemical manipulations to which it was subjected in my work, as also on the ground of its physiological properties.