Methods of inhibiting osteoclast activity

A method for treating bone loss in a patient, which method comprises the step of administering to said patient an amount of an inhibitor of TNF-related activator induced cytokine (TRANCE)/Receptor activator of NF-B ligand (RANK) that is effective to inhibit osteoclastogenesis or osteoclast function, wherein the inhibitor is a specific peptide having the formula:

• R1—R2—R3—R4—R5
• wherein:
• R1 is 1-5 amino acid residues;
• R2 is a linking amino acid residue;
• R3 is selected from the group consisting of DRGWA (SEQ ID NO:1);
• DGDLAT (SEQ ID NO:2);
• SDFATE (SEQ ID NO:3);
• VKTSIKIPSSH (SEQ ID NO:4);
• TKTSIKIPSSH (SEQ ID NO:5);
• KTSIKIPSSH (SEQ ID NO:6);
• YWSNSEF (SEQ ID NO:7);
• YWNSE (SEQ ID NO:8);
• PDQDAP (SEQ ID NO:9);
• PDSWH (SEQ ID NO:10);
• SKEL (SEQ ID NO:11);
• EIEF (SEQ ID NO:12);
• SRSGHS (SEQ ID NO:13);
• RFQEEIKENTKNDKQ (SEQ ID NO:14);
• TSYPD (SEQ ID NO:15);
• KENTK (SEQ ID NO:16);
• and SEQ ID NOS:1-16 with one or more amino acid residues substituted with another residue in the same designated class;
• R4 is a linking amino acid residue;
• R5 is 1-5 amino acid residues;
• and
• wherein R2 and R4 are bound to each other, thereby forming a cyclic portion which includes R2, R3 and R4 with R1 and R5 forming exocyclic portions, and one or both of R1 and R5 comprising at least one tyrosine or phenylalanine.