hypothalamohypophysial portal system

[hī′pō-thăl′ə-mō-hī′pə-fĭzē-əl, -zē-, -hī-pŏf′ĭ-sēəl]
n.
  1. A system of veins that originate in the hypothalamus and pass through the pituitary gland and into its anterior lobe, where they branch into a capillary bed and convey releasing factors to the anterior lobe.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.