Synonyms: Oxytocin,8-L-arginine-9a-glycine-9b-L-lysine-;1,2-Dithia-5,8,11,14,17-pentaazacycloeicosane, cyclic peptide deriv.; Hydrin 1'(Xenopus laevis pituitary); L-Lysine,L-cysteinyl-L-tyrosyl-L-isoleucyl-L-glutaminyl-L-asparaginyl-L-cysteinyl-L-prolyl-L-arginylglycylglycyl-,cyclic (1®6)-disulfide