Immunocytochemical study of the GH cells in the anterior pituitary gland of human fetus II. Anencephalic fetus

In order to elucidate the effects of hypothalamic regulation on the morphology of GH cells, light and electron microscopic immunocytochemical examinations were carried out comparing GH cells in the anterior pituitary gland of anencephalic fetus with those of normal fetuses. Three types of GH cells were identifted in the anterior pituitary gland of anencephalic fetus as well as in the normal fetus. Type1 is a small, round cell containing a few small secretory granules. Type-III is a large, polygonal cell with numerous large secretory granules. Type-II is a polygonal cell with medium-sized secretory granules. The Type-II GH cell was predominant in both anencephalic and normal fetuses. The most striking difference between anencephalic and normal fetuses was the presence of atypical forms of the Type II cell. These were polygonal cells containing secretory granules, which were either immunopositive or imrnunonegative to anti-human GH (anti-hGH) serum. Furthermore, two other types of GH cells were identified. The somatomammotroph (SM cell) contained GH and PRL. in different granules within the same cell. Also. a different type of the GH cell was noted containing two varieties of secretory granules; one was immunolabeled only with anti-hGH and the other was not irnmunolabeled to either anti-hGH or anti-human PRL (anti-hPRL). From these results, we suggest that an absence of hypothalamic regulation in the anencehpalic does not seriously modify GH cell morphology but induces an altered GH storage pattern in some of the cells.