Bromoacetylalprenololmenthane binding to β‐receptors modulates the rate of hormone‐induced internalization but not desensitization in S49 cells

Bromoacetylalprenololmenthane was found to inhibit hormone-induced beta-adrenergic receptor internalization in a dose-dependent fashion in S49 lymphoma cells, besides its known ability to bind to beta-receptors irreversibly. This new found property of BAAM+ was taken advantage of in studying whether receptor internalization is a necessary step in the desensitization of adenylate cyclase. BAAM-treated cells showed functional desensitization even when receptor internalization had been blocked substantially by 50-65%. This finding suggests that receptor internalization is not directly involved in desensitization.