Electron microscope observation of "thyroidectomy cells" in the hypophyseal ventral lobe of a Chondrichthyan fish, the small spotted dogfish, Scyllium canicula Cuv.]

In the adenohypophysis of very young spotted dogfish, only one kind of granulated cells show strcutural changes following thyroidectomy: the small granule cells of the ventral lobe (granule diameter about 110 nm). These cells are similar to the thyrotrophs of other Vertebrates, and well distinct from the supposed gonadotrophs found in the same lobe.