Polypeptides having a .beta.-adrenergic receptor activity in man, implicated in the lipolytic response, nucleic acids coding for these polypeptides and the use of these polypeptides for the screening of a substance active on these polypeptides

A substantially pure polypeptide having a .beta.-adrenergic receptor activity comprising:

• the sequence of 402 amino acids of FIG. 12, or a fragment of said sequence, wherein said fragment contains sites in this sequence such that when this fragment is exposed at the surface of a cell, it is capable of participating in the activation of adenylate cyclase in the presence of an agonist, this activation increasing in the order of the agonists as follows:
• salbutamol, ##STR4## (1)-isoproterenol or said fragment is capable of being recognized by antibodies which also recognize the above-mentioned sequence of 402 amino acids, but which do not recognize the .beta.1-adrenergic receptor or the .beta.2-adrenergic receptor,
• or said fragment is capable of generating antibodies which recognize the above-mentioned sequence of 402 amino acids but do not recognize either the .beta.1-adrenergic receptor or the .beta.2-adrenergic receptor.