Neuropeptide tyrosine (NPY) immunoreactivity in norepinephrine-containing cells and nerves of the mammalian adrenal gland.

The application of immunocytochemistry at both light and electron microscopic levels has revealed neuropeptide tyrosine (NPY)-immunoreactive material to be localized to norepinephrine-containing endocrine cells in the adrenal medulla and also to varicose nerve fibers penetrating the adrenal cortex of several mammalian species, including horse, cat, rat, guinea pig and mouse. Correlative electron microscopic immunostaining has revealed that enkephalin and NPY immunoreactivities are co-localized to the same norepinephrine-containing secretory granules. High concentrations of NPY have been extracted from the mouse adrenal gland (1243.7 +/- 122.8 pmol NPY/g wet tissue; mean +/- SE). Chromatographic analysis has shown the extracted material to correspond with pure natural NPY.