The present invention provides isolated polypeptides having an amino acid sequence having at least 70% identity to SEQ ID NO:20, wherein the polypeptide has ER-α36 activity. The invention further provides methods for identifying agents that bind to such polypeptides, methods for detecting such polypeptides, and methods for altering the activity of such polypeptides. Also provided are antibodies that specifically bind to an amino acid sequence depicted at SEQ ID NO:1, or an immunogenic fragment thereof, and methods for making and using such antibodies.