Distribution and development of angiotensin converting enzyme in the fetal and newborn rabbit. An immunofluorescence study.

The distribution and development of angiotensin converting enzyme (EC 3.4.15.1) were studied in fetal and newborn rabbits, using fixed tissues embedded in paraffin and stained with a fluorescein-conjugated antibody specific for the enzyme. The enzyme was found at the luminal plasma membrane of endothelial cells from the second third of gestation to the neonatal period. In addition, two types of epithelial cells also contained the enzyme, renal tubular and intestinal. The vascular enzyme may play a role in the regulation of its vasoactive peptide substrates, angiotensin and bradykinin, at term.