Histostructure of adenohypophysis of human fetuses and contents of somatotropic and adrenocorticotropic hormones

Abstract

Histochemical study of adenohypophyses of human fetuses was carried out in combination with quantitative determination of the content of STH and ACTH in them. STH and ACTH appeared first in trace amounts in hypophyses of 9-week-old fetuses. At this point, the amount of STH increased rapidly coinciding with periods of rapid differentiation of acidophilic cells in the gland (11–16 weeks of age). Concentration of ACTH in the human hypophysis does not change significantly from 10 to 19 weeks of embryonal life. A definite increase in its amount is observed beginning at 20–22 weeks of intrauterine life. At this period in the gland there appears a great number of cells whose cytoplasm gives a weak reaction for mucoproteins. The observed changes in the structure of the adenohypophysis in combination with the results of assay of STH and ACTH indicate a close relationship between the level of morphological differentiation of the gland and STH and ACTH content contained within it. An increase in the number of acidophilic cells always coincides in time with an increase of STH content in human fetal hypophyses; appearance in the gland of large numbers of cells whose cytoplasm contains only traces of mucoprotein coincides with a considerable increase of ACTH content.