Neuronal localization of pituitary adenylate cyclase-activating polypeptide 38 in the adrenal medulla and growth-inhibitory effect on chromaffin cells

摘要: The chromaffin cells of the adult rat adrenal medulla are essentially growth arrested in situ, but can proliferate vitro, suggesting existence inhibitory factors gland. We have investigated whether pituitary adenylate cyclase-activating polypeptide 38 (PACAP38) could be involved arrest cells. In gland, PACAP38 was detected by radioimmunoassay and high-performance liquid chromatography its concentration estimated as 24 nmol/kg wet tissue. Immunohistochemistry neonatal showed immunoreactivity a widely distributed network delicate nerve fibers surrounding primary culture system, inhibited factor-stimulated DNA synthesis 90% with half-maximal inhibition at 4 0.5 nM, respectively, demonstrated bromodeoxyuridine pulse-labeling immunocytochemical staining cell nuclei. comparison, corticosterone proliferation 70% 95%, effect 100 nM. cells, nM 1 microM added together abolished completely (99.8% inhibition). Finally, increased survival little neurite-promoting activity Our data suggest that neurally derived PACAP38, conjunction glucocorticoids, may override factor mitogenic signals, leading to postmitotic state medulla.