Neurosecretory substances released in the median eminence by hypothalamic cells diffuse into blood within capillaries of the median eminence, and are directly transported to the sinusoids of the pars distalis by way of the hypophysial portal veins. Several of these neurosecretory substances are known to affect the release of hormones by cells of the pars distalis. The studies on the release of hypothalamic dopamine into hypophysial portal blood pertain to dopamine in blood collected from all of the portal vessels after transection of the pituitary stalk. Such results are reflective of the concentration of dopamine in the mixture of blood from all the vessels of the stalk. The rate of release of dopamine by hypothalamic neurons into hypophysial portal blood is subject to modification by a variety of agents and conditions.
ASJC Scopus subject areas
- Molecular Biology