The measurement of neuropeptide Y in discrete hypothalamic and limbic regions of male rhesus macaques with a human NPY-directed antiserum.

The distribution of neuropeptide Y (NPY) in microdissected brain regions of male macaques was quantified with a specific radioimmunoassay (RIA). The RIA consisted of a specific antiserum (R31) against human NPY that could detect 7 pg/tube with an IC50 of 125 pg/tube at a final dilution of 1:20,000. Varying amounts of rabbit and monkey mediobasal hypothalami yielded parallel [125I]NPY displacement curves in the assay and similar chromatographic elution profiles with those of synthetic human NPY. The NPY activity in acid extracts of discrete brain regions in castrate and castrated-testosterone-treated rhesus males was highest in mediobasal hypothalamus, followed by more rostral hypothalamic regions and amygdaloid nuclei. Testosterone did not alter NPY levels in any of the brain areas that we examined.