Isolated growth hormone deficiency: immunocytochemistry.

Light and electron microscopic immunocytochemistry of the pituitary gland of a patient with documented isolated GH deficiency revealed parenchyma rich in GH positive cells. Immunoprecipitate was localized consistently over membrane-enclosed secretory granules whose features were characteristic of those in normal somatotrophs. No profiles of exocytosis of the contents of the secretory granules were observed. These observations demonstrate that the type I recessive form of isolated GH deficiency may be associated with apparently normal appearing somatotrophs which contain immunoreactive GH.