3H-Spiroperidol labels dopamine receptors in pituitary and brain

3H-Spiroperidol of high specific radioactivity labels dopamine receptors in membranes of bovine caudate nucleus and anterior pituitary. The saturation and kinetic properties of 3H-spiroperidol binding are similar in the two tissues. In both caudate and pituitary 3H-spiroperidol displays very high affinity with a dissociation constant of 0.2-0.3 nM. The relative potencies of numerous dopamine agonists and antagonists in competing for 3H-spiroperidol binding are closely similar in anterior pituitary and caudate.