Localization of adrenaline in cytoplasmic particles of the bovine adrenal medulla - Naunyn-Schmiedeberg's Archives of Pharmacology

1. Cell-free homogenates of the bovine adrenal medulla, prepared in ice-cold isotonic sucrose, contain at least two-third of their pressor activity in a fraction of granules which can be sedimented on a fast centrifuge.

2. These granules, when resuspended in isotonic sucrose at 0° C, do not give up much adrenaline to the surrounding fluid.

3. If the fresh undenatured granules are injected into the spinal cat, the blood pressure rise shows a maximum equal to that attained after the injection of one-fifth of their adrenaline content; the return of blood pressure to normal is less rapid than after a dose of adrenaline.

4. These findings are discussed in relation to the problems of release and secretion.