Resumen de Apoptosis is involved in the anti-proliferative effect of corticosteroid in non-tumoral ACTH pituitary cells

M.C. Montero, Ricardo Vázquez, Manuel Rubio Sánchez, Enrique J. Blanco Barco, José Manuel Riesco Santos, J.J. Herrero, G. Vázquez, R. Gonzalez, M. Carretero, M. Basco, José Carretero González

• Glucocorticoids are the physiological negative feedback on ACTH secretion and may be involved in regulating the maintenance of the population of hypophyseal ACTH-cells, because following surgical ablation, adrenalectomy induces an increase in the number of these cells in the early stages. Glucocorticoids have been implicated in the induction of apoptosis in several tissues; but they have been little considered as hormonal inducers of apoptosis in the pituitary gland. By means of a double immunohistochemical study for PCNA and ACTH and a double assay by ISEL and immunohistochemistry for ACTH, the aim of the present study was to analyse whether corticosterone induces apoptosis and inhibits cellular proliferation to control non-tumoral ACTH-cells in the pituitary gland. For this purpose untreated, sham-operated and adrenalectomized rats, treated or not with corticosterone, were compared. The results of the present study demonstrate a very important decrease in proliferation and an increase in apoptosis of pituitary ACTH-positive cells induced by corticosterone, suggesting that the number of pituitary ACTH-producing cells is mainly controlled by glucocorticoids by means of cellular proliferation and apoptosis.