The Ability of ATP-Free Granule Material from Bovine Adrenal Medulla to Bind Inorganic Cations and Biogenic Amines

Abstract

Bovine adrenal medullary granules isolated by Millipore filtration were depleted of CA [catecholamines] and ATP by dialysis. The resulting material showed an ability to bind inorganic cations and biogenic amines in a concentration-dependent manner. The similarity of the uptake curves, the identical uptake maxima and the narrow pH range (between 4-7) over which the uptake of the inorganic and organic cations took place indicated a binding of these ions to common sites. In addition, the fact that all the uptake curves fitted the Rothmund-Kornfeld equation for cation exchangers corroborated the cation exchanger properties of the dialyzed granule material. The CA binding capacity corresponded to 20-30% of the normal CA content of bovine medullary granules.