Immunocytochemical localization of thyroglobulin in the endostyle of the anadromous sea lamprey, Petromyzon marinus L.

Thyroglobulin (TG) was localized in the endostyle of the anadromous sea lamprey, Petromyzon marinus L. by means of the unlabeled antibody peroxidase-antiperoxidase immunocytochemical method. TG was found localized on the apical surface and within the cytoplasm of type 2c and 3 cells and in some type 5 cells. By identifying the cells of the endostyle immunocytochemically it may be possible to study more readily the events of endostylar transformation during metamorphosis.