Table 2. OT Analogues with OTR Preference or Selectivity over VPRs.

^aRSR, receptor selectivity ratio: calculated dividing highest receptor selectivity among receptors by OTR affinity.

^bDisulfide bridge formed with substituted dibromoxylene (m-xylene bridged between residues 1 and 6).

^cthio = S–S bridge was substituted for CH₂–S, with CH₂ in position 6.

^dBuG, N-(n-butyl)glycine.

^ethP = trans-4-hydroxyproline.

^fL(Me) = γ-methylleucine.

^gthio = S–S bridge was substituted for CH₂–S, with CH₂ in position 1.

^hX′ amino acids used to form a lactam bridge.

ⁱzG = azaglycine.

^jG(2-ThiMe) = N-alkylated glycines with 2-thiophenylmethyl.

^kMeBzlG = N-(3methylbenzyl)glycine.

^lFBzlG = N-(4-fluorobenzyl)glycine.

^mC₈ = octanoic acid.

ⁿBiphasic fitting (Hill coefficient for both phases was fixed to −1; “EC₅₀ hi” refers to the high-affinity site and “EC₅₀ lo” to the low-affinity site.¹⁷⁸ All assay values were obtained from pharmacological testing on human isoforms of OTR, V_1aR, V_1bR, and V₂R. *Analogues are based on OT sequence (indicates C-terminal amide). **K_i values are presented in white, EC₅₀ values in gray. n.d. = not determined; “d” = for desamino (no N-terminal amine); d(CH₂)₅ = 1-[β-mercapto-β,β-cyclopentamethylene]propionic acid.