the very potent opioid peptide , dynorphin , has recently been shown by radioimmunoassay and immunocytochemical techniques to be selectively concentrated in the pars nervosa of pituitary , suggesting a possible association of dynorphin with the neurohypophyseal hormones , vasopressin and oxytocin .
C0032017
neurohypophyseal hormones
C0030095
oxytocin