Immunohistochemistry employing immunoglobulin G fractions raised against aromatase cytochrome P-450 and antiserum against 17β-estradiol dehydrogenase was used to localize these two steroid-converting enzymes in the human placenta. Immunostaining for both enzymes was found exclusively in the syncytiotrophoblast, while the underlying cytotrophoblast and the villus core did not stain. Ultrastructural examination of aromatase cytochrome P-450- and 17β-estradiol dehydrogenaselabeled sections disclosed immunoreactive product in the membranes of the endoplasmic reticulum; the nucleus, mitochondria, Golgi apparatus, and secretory granules were free of staining. These findings suggest that the syncytiotrophoblast is actively involved in the synthesis and metabolism of estrogens and in their role in placental endocrine function.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical