Rathke's pouch during autoimmune inflammation of the rat pituitary.

Allergic adenohypophysitis was produced in rats by injection of anterior lobe tissue, Freund's adjuvant, and pertussis vaccine. In addition to the inflammatory changes in the parenchyma, fluid and inflammatory cells were found in the lumen of Rathke's pouch. The cells entered the lumen through small ulcers of the lining of the anterior wall of the pouch. Pituitaries with inflammation were increased in size and weight. The enlargement was caused mostly by dilation of Rathke's pouch with fluid and cells.