Pituitary gland. Coloured Scanning Electron Micro- graph (SEM) of the pars intermedia region of the pituitary gland. The pituitary gland (hypophysis) is the master endocrine gland, located at the base of the skull. At lower frame (green) is the pars intermedia or middle region of the gland which has rounded hormone-secreting cells (blue).Melanocyte- stimulating hormone (MSH) is secreted here. At top (pink) is the posterior region (neurohypophysis) of the gland. An arteriole with red blood cells is visible at the junction of these regions. Each region of the pituitary secretes different hormones. Magnification: x1,000 at 6x7cm size. x1,430 at 4x5"~LANDSCAPE"