Radioiodination of p-hydroxyphenylisopropyladenosine: development of a new ligand for adenosine receptors.

dl-p-Hydroxyphenylisopropyladenosine has been iodinated with 125I and tested as a ligand of adenosine receptors in membranes from rat brain using a filtration assay. Binding studies using l-[3H]phenylisopropyladenosine as a ligand were carried out in parallel, and the binding of both ligands could be displaced by dl-p-hydroxyphenylisopropyladenosine and l-phenylisopropyladenosine in a similar fashion. These data establish the feasibility of using radioiodinated derivatives of adenosine as ligands of suitable types of adenosine receptors.