Release of oxytocin from the rat posterior pituitary lobe incubated in situ and from the hypothalamic end of the cut pituitary stalk.

Release of oxytocin from the rat posterior pituitary lobe incubated in situ and from the hypothalamic end of the cut pituitary stalk. Acta Physiol. Pol., 1978, 29 (2):97--105. Using the method of incubation in situ of the posterior pituitary lobe and washing the hypothalamic end of the divided pituitary stalk the activity of neurosecretory neurons was investigated directly. The oxytocic activity of the fluid incubating in situ the posterior pituitary lobe or washing the hypothalamic end of the cut pituitary stalk was determined on the rat myometrium. The oxytocic activity disappeared from this fluid after inactivation with sodium thioglycolate. The samples of the fluid incubating the posterior pituitary lobe obtained at 30 min intervals showed alternatingly increased or decreased oxytocic activity. In the fluid washing the cut pituitary stalk the activity was highest from 31 to 60 minutes after division of the stalk.