Corticotrophs in the Anterior Pituitary Glands of Gonadectomized and Thyroidectomized Rats as Revealed by Electron Microscopy

Abstract

The anterior pituitary glands of rats at various stages after gonadectomy and after thyroidectomy were observed with the electron microscope. The most prominent changes occurred in the cells which produce the trophic hormones stimulating the target organs that were extirpated in the experiment. Corticotrophs are characterized in the normal state by the presence of secretory granules with a marked halo around each granule. These cells underwent slight morphological alteration after surgical ablation of the gonad or thyroid. However, the secretory granules of the corticotrophs increased somewhat in number shortly after the ablation of target organs, and, within 4 weeks after thyroidectomy, most of the corticotroph granules appeared to be solid and dense. These facts indicate the possibility that the corticotrophs are influenced to a considerable extent by gonadectomy and thyroidectomy. As these changes in the corticotrophs were always less marked than those in the gonadotrophs or thyrotrophs after gonadectomy or thyroidectomy, respectively, it is evident that the corticotroph is an independent cell type which is different from both the gonadotroph and thyrotroph.