Ultrastructural study of the adenohypophysis of the Chinese hamster.

The adenohypophysis of normal Chinese hamsters of both sexes was examined ultrastructurally. Organs were fixed by intravascular perfusion with S-collidine-buffered glutaraldehyde solution. Seven types of cells were differentiated and, according to morphological characteristics, classified as (1) mammotropes, with very large (400-800 nm) polymorphous secretory granules; (2) somatotropes, either in the storage phase with numerous large, dense granules (average 300 nm), or in the hormone synthesis phase, with abundant endoplasmic reticulum and large Golgi apparatus; (3) corticotropes, with irregular cell shape, and granules (average 160 nm) arranged in lines parallel to the cell membrane; (4) FSH gonadotropes, with abundant and dilated endoplasmic reticulum, and granules (190-320 nm) uniformly distributed in the cytoplasm; (5) LH gonadotropes, with granules (120-220 nm) of varied density; (6) thyrotropes, with irregular cell shape and very small granules (120-160 nm), and (7) agranulated cells. The ultrastructure of the adenohypophysis of the Chinese hamster corresponds closely with observations reported in rats, mice and Syrian hamsters.