<prompt> Half life biological of oxytocin:2-3 min3-4 min5-6 min7-8 min  <response>: OxytocinIt is a nonapeptide Peptide of nine amino acids.Released by posterior pituitary and synthesized in the supra optic and paraventricular nucleus of hypothalamus.Half life 34 minutes.Duration of action 20 minutes.Mechanism of action Acts through calcium mediated channels to initiate myometrial contractions. 