Electron microscopical studies of pituitary gland of male hamsters under the effect of estrogen treatment

The ultrastructure of the normal pars intermedia of male hamsters showed two types of cells. The light cells were numerous, regular in shape with rounded or elongated nuclei have different size of secretory granules and were considered as a source of melanocyte stimulating hormone [MSH]. The dark cells were less in number, showed less display of secretory granules and were concerned with colloid production. Some of the dark cells showed foot like processes and irregular nuclear membranes. Progressive changes in the cell organelles were observed in the pars intermedia cells after long term of estrogen treated hamsters over the studied period