
Elevated levels of Glu and Asp in the blood are able to bypass the
Blood-brain barrier through the circumventricular organs (or CVO), in
particular the adeno and neurohypophysis (pituitary gland) areas.  The
arcuate nucleus of the hypothalamus, and the median eminence regions
are particularly effected.  CVO areas are not subject to the
blood-brain barrier. These areas control the release of gonadotropin,
which controls the release and flux of steroids governing development,
especially sexual development. Changes in adult rats, which are less
sensitive to Glu than humans, have been observed: after ingesting Glu,
on a chronic basis, cycles of several steroids are disrupted. Blood
levels of somatostatin are significantly reduced, and cyclic release
of steroids becomes flattened.