Abstract
Observations of ACTH and TSH-producing cells of the rat pituitary studied immunohistochemically in thick sections were correlated with observations of adjacent thin sections studied by electron microscopy. ACTH-containing cells are small and stellate, with poorly developed organelles and granules ≤250nm in diameter. TSH cells are much larger, contain well-developed intracellular organelles, and variable sized granules (≤270nm), some of which appear in vesicles with dense cores. In addition, TSH cells show ultrastructural changes in response to adrenalectomy.
