Neuropeptide Y in bovine adrenal glands: distribution and characterization.

Neuropeptide Y (NPY) distribution in bovine adrenal glands was studied by RIA and immunohistochemical technique. NPY content (picomoles per mg protein +/- SEM) of chromaffin cells, medulla, cortex, and whole glands was 4.2 +/- 0.16, 2.7 +/- 0.28, 0.19 +/- 0.02, and 0.94 +/- 0.14, respectively, while the chromaffin granule NPY content was 53. Immunohistochemically, NPY immunoreactivity was detected in norepinephrine containing chromaffin cells and also in nerve fibers crossing through adrenal cortex and medulla. NPY and enkephalin immunoreactivities were found in distinct chromaffin cells. Biochemical characterization by HPLC revealed two major NPY immunoreactive peptides. The most abundant molecular form was identified as authentic NPY.