Journal of Neuroscience, Vol 4, 1248-1252, Copyright © 1984 by Society for Neuroscience
Distribution of immunoreactive beta-neo-endorphin in discrete areas of the rat brain and pituitary gland: comparison with alpha-neo-endorphin
N Zamir, M Palkovits and MJ Brownstein
The distribution of immunoreactive (ir)-beta-neo-endorphin in 101
microdissected rat brain and spinal cord regions as well as in the
neurointermediate lobe of pituitary gland was determined using a highly
specific radioimmunoassay. The highest concentration of beta-neo- endorphin
in brain was found in the median eminence (341.4 fmol/mg of protein). High
concentrations of ir-beta-neo-endorphin (greater than 250 fmol/mg of
protein) were found in 11 nuclei, including dorsomedial nucleus, substantia
nigra, parabrachial nuclei, periaqueductal gray matter, anterior
hypothalamic nucleus, and lateral preoptic areas. Moderate concentrations
of the peptide (between 100 and 250 fmol/mg of protein) were found in 66
brain nuclei such as the amygdaloid and septal nuclei, most of the
diencephalic structures (not including the hypothalamus), and the majority
of the medulla oblongata nuclei and others. Low concentrations of
ir-beta-neo-endorphin (less than 100 fmol/mg of protein) were found in 21
nuclei, e.g., cortical structures (frontal., cingulate, piriform, parietal,
entorhinal, occipital), olfactory tubercle, and cerebellum (nuclei and
cortex). The olfactory bulb has the lowest beta-neo-endorphin concentration
(21.3 fmol/mg of protein). Spinal cord segments exhibit low peptide
concentrations. The neurointermediate lobe of the pituitary gland is
extremely rich in ir- beta-neo-endorphin.