Immunocytochemical evidence for the ability of the human pharyngeal hypophysis to respond to change in endocrine feedback.

Two pharyngeal hypophyses from patients with endocrine disorder were examined light microscopically and immunocytochemically. The pharyngeal hypophysis from a patient with primary hypothyroidism was hypertrophic, with TSH cell hyperplasia; while that from a patient treated with metoclopramide, a dopamine-receptor-blocking drug, showed PRL cell hyperplasia. These findings strongly suggest that under certain circumstances the pharyngeal hypophysis is able to respond with specific changes to variations in the endocrine feedback.