17α-Hydroxylase and Chromogranin A in 6th Week Human Fetal Adrenals

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