The development of the human fetal adrenals starts in the 6th week gestational age
and adrenal C19 steroid production becomes of major importance for the maintenance of the pregnancy.
Therefore, in the present study, human fetal adrenals at 6 weeks of gestational age
were immunostained for 17α-hydroxylase, the key enzyme for the production of C19-steroids. In parallel, chromaffin cells were characterized by immunohistochemical
staining for chromogranin A, the major soluble protein in adrenal chromaffin granules.
Large 17α-hydroxylase-immunoreactive cells were found in the center of the adrenal
anlagen during the 6th week of gestation. At the same developmental stage, chromaffin
cells with a neuronal-like appearance occurred in the paraaortic area and started
to invade the adrenal primordium. Our results show that, even at week 6 gestational
age, when chromaffin cells start to enter the adrenal anlagen, human adrenals already
contain differentiated, 17α-hydroxylase immunoreactive cortical cells which were located
to the center of the primordium.
Key words
Fetal Development - Immunohistochemistry - Adrenal Medulla - Adrenal Cortex
