Effects of bilateral olfactory bulbectomy on the anterior pituitary corticotropic cell activity in male rats

Bilateral olfactory bulbectomy (OB) has drastic biochemical and behavioral effects and is often associated with an increase in plasma corticosterone c oncentrations. This experiment examined the effects of OB on adrenocorticot ropin (ACTH) and corticosterone release under basal and stress conditions a nd on proopiomelanocortin (POMC) gene expression. Bulbectomy potentiated hy pophysal ACTH and adrenal corticosterone release induced by ether stress bu t had no effect on ACTH release under basal conditions, despite a significa nt increase of circulating corticosterone. POMC gene expression was stronge r (+60%) in OB rats than in sham-operated rats. These results suggest that olfactory bulbectomy substantially altered the negative feed-back exerted b y glucocorticoids on anterior pituitary corticotropic cells in the male rat .