Regional distribution of leucine-enkephalin in hypothalamic and extrahypothalamic loci of the human nervous system.
The recent discovery of the endogenous opioid peptide, leucine-enkephalin (L-E), throughout vertebrate species prompted investigation of its potential presence in the human CNS using a specific radioimmunoassay. Twenty CNS structures were dissected from 5 human brains obtained at autopsy and were extracted with 2 N and glacial acetic acid. L-E immunoreactivity, identical to synthetic standard, was found in all structures examined. Highest concentrations (range 76-650 pmol/g wet wt.) were found in the pituitary, infundibular stalk, globus pallidus, putamen, substantia nigra, amygdala, head of caudate, and hypothalamus. Lowest concentrations (range 23-49) were found in frontal cortex and cerebellum. L-E was also found in the spinal cord. It is concluded that L-E immunoreactivity is present in the human CNS. The correspondence between the distribution of L-E and the opiate receptor suggests that L-E represents a biologically significant endogenous opiate in man. The high concentrations of L-E in the human hypothalamus and pituitary raises the possibility of a neuroendocrine role for this peptide.
D001923:Brain Chemistry; D004743:Enkephalin, Leucine / Q000032:analysis*; D006801:Humans; D007031:Hypothalamus / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods; D013116:Spinal Cord / Q000032:analysis*; D014018:Tissue Distribution
D004743:Enkephalin, Leucine