The involvement of nitric oxide in the secretion of β-endorphin from the pituitary intermediate lobe of the rat

Abstract

Nitric oxide (NO) generated by the enzyme nitric oxide synthase (NOS) has been implicated in the regulation of a variety of endocrine functions. A number of biochemical and anatomical studies have demonstrated the presence of neuronal NOS (nNOS) in the neuroendocrine axis and have shown significant effects of NO on the release of hypothalamic and pituitary hormones. Using a C-terminal directed peptide antibody that is specific for nNOS we have found a predominance of nNOS in the neural lobe of the pituitary and in a single layer of epithelial cells, possibly a remnant of Rathke's pouch that form a border between the intermediate lobe and the anterior lobe. Furthermore, we have examined the e..