Further evidence that desensitization of beta-adrenergic-sensitive adenylate cyclase proceeds in two steps. Modification of the coupling and loss of beta-adrenergic receptors.

In c6 glioma cells adenylate cyclase activation by a P-adrenergic agonist is a Michaelis-Menten function of receptor occupancy as expected in the collision-coupling model.The apparent affinity of the receptor-agonist complex for the adenylate cyclase ( K ) is equal to 0.24 X [RT], [RT] being the maximal receptor concentration.When c6 glioma cells were incubated with lo-' M