Disclosed is a compound represented by Formula I: T-L-P, or pharmaceutically acceptable salts thereof, wherein: P is a peptide comprising at least thirteen contiguous amino-acid residues derived from an intracellular il loop of the APJ receptor L is a linking moiety represented by C(O) and bonded to P at an N terminal nitrogen of an N-terminal amino-acid residue and T is a lipophilic tether moiety bonded to L where the C-terminal amino acid residue of P is optionally functionalized, wherein P is derived from the il loop and is represented by the following structural formula or pharmaceutically acceptable salts thereof, X1-X2-X3-X4-X5-X6-X7-X8-X9-X10-X11-X12-X13-X14-X15-X16-X17-X18-X19-Ri, wherein: X1 is absent or a threonine X2 is absent or a valine X3 is absent or a phenylalanine X4 is absent or an arginine X5 is a serine X6 is a serine X7 is an arginine X8 is a glutamic acid X9 is a lysine X10 is an arginine X11 is an arginine X12 is a serine X13 is an alanine X14 is an aspartic acid X15 is an isoleucine X16 is a phenylalanine X17 is an isoleucine X18 is absent or an alanine X19 is absent or a serine residue Ri is OR2 or N(R2)2 each R2 is independently hydrogen or (C1-C10)alkyl and from 0 to 1 amino acid residues are present in the D configuration and wherein from 0 to 1 amino acid residues may be substituted by alanine
