MH 150a Pituitary

Pituitary

The azan stain intensifies the differences between acidophils, basophils, and chromophobes.

• Anterior Pituitary - contains three divisions:
  • Pars Distalis - comprises most of the anterior lobe (~75%) and contains five types of endocrine cells.
    • Chromophils - stain with H&E and secrete hormones.
      • Acidophils - stain dark red with azan.
        • Somatotrophs - growth hormone (GH).
        • Mammotrophs (Lactotrophs) - prolactin.
      • Basophils - stain dark blue with azan.
        • Corticotrophs - ACTH.
        • Thyrotrophs - TSH.
        • Gonadotrophs - FSH and LH.
    • Chromophobes - stain light blue with azan and do not secrete hormones.
    • Sinusoidal Capillaries - extensive network that receives hormones from acidophils and basophils.
  • Pars Tuberalis - not shown.
  • Pars Intermedia - thin remnant (<2%) at interface between the anterior and posterior lobes that contains numerous colloid (protein)-filled (blue) cysts (Rathke's cysts).
• Posterior Pituitary - axons from the hypothalamus that release hormones into the capillaries of the pars nervosa.
  • Pituicytes - most nuclei belong to these glial cells.
  • Herring Bodies (#1, #2 and #3) - dilations of axons filled with neuro-secretion vesicles.