PRL and pituitary gland adenoma: NO plays an important role to activate the release of luteinizing hormone-releasing hormone (LHRH) and follicle-stimulating hormone-releasing hormone (FSHRH) from the hypothalamus, and of LH and FSH from the pituitary [40-42]; to stimulate or inhibit the secretion of PRL [43]; to regulate the secretion of growth hormone (GH) in the normal human pituitary and in acromegaly [44,45]; and to modulate GH secretion in a dose-dependent manner in GH adenomatous cells from human pituitary adenomas [46].