Manserin, a novel peptide from secretogranin II in the neuroendocrine system

We have isolated a novel 40 amino acid neuropeptide, designated manserin, from the rat. Manserin is derived from secretogranin II (SgII), a member of granin acidic secretory protein family by proteolytic processing, as previously reported secretoneurin and EM66. Immunohistochemical analysis using anti-manserin antibody revealed that manserin localized in the endocrine cells of the pituitary anterior lobe, but not in the posterior lobe. Interestingly, manserin never co-localized with ACTH in the anterior pituitary, which is in contrast with SgII, suggesting specific immunoreactivity of the antiserum against manserin. Manserin immunostaining was also observed in the neuronal cells of several hypothalamic nuclei and the neurons in the median eminence. These results suggest that manserin exerts a specific role in the neuroendocrine system.