In vivo effects of 2-substituted [Mpa(1)Sar(7)Arg(8)]-oxytocin antagonistson postpartum rat

A set of oxytocin antagonists consisting of [Mpa(1)Sar(7)Arg(8)]-oxytocin s ubstituted by various conformationally restricted or bulky D amino acids at position 2 ware synthetized and biologically tested. In in vivo pharmacolo gical investigations, the effects of these peptides were examined on the sp ontaneous motor activity of postpartum rat. Three of the newly prepared pep tides proved at least as effective in inhibiting uterine contractions as cl inically investigated atosiban. (C) 1999 Elsevier Science Inc. All rights r eserved.