Somatotrophs in the human fetal anterior pituitary. An electron microscopic-immunocytochemical study.

An immunocytochemical staining of ultrathin sections using the peroxidase-antiperoxidase complex was employed to localize the somatotrophs in the anterior pituitary of the human fetus. This technique allowed a specific identification of the somatotrophs and a detailed description of their ultrastructure which was well preserved by the fixation employed. They appeared as cells with a dense cytoplasmic matrix, lamellar rough endoplasmic reticulum, and prominent Golgi apparatus. Their secretory granules had a mean diameter of 300 nm.