Abstract
The functional differentiation of the posterior limb of Rathke's pouch in the human fetal pituitaries of gestational age ranging from 5 weeks to 24 weeks was studied by the peroxidase-labeled antibody method, using antibodies against ACTH, ACTH17-39, MSH, GH, PRL, TSH and LH. Our results indicated that ACTH was the first hormone localized in the posterior limb at 5 weeks, and the posterior limb possessed the potentiality of the differentiation to MSH, GH, PRL and LH secreting cells. However, ACTH and MSH remained as the predominant hormone secreted by the posterior limb cells. Possible mechanism to promote ACTH and MSH secreting cells is also discussed.
