Do Human Vascular Endothelial Cells Produce Aldosterone?

Extraadrenal production of aldosterone has been reported in several tissues, including vascular endothelial cells. The implications of local production of aldosterone in certain nonepithelial target tissues in normal and pathological physiology could be very important and merits further investigation. Human vascular endothelial cells have been reported to synthesize aldosterone under the regulation of angiotensin II. However, discrepancies are noted upon close scrutiny, the most important of which are the relative large efficiency of deoxycorticosterone conversion to aldosterone and the rate of aldosterone production in comparison to the adrenal zona glomerulosa cells. We investigated the production of aldosterone in three different human vascular endothelial cell lines, two from human umbilical veins, one from human pulmonary artery endothelial cells using a very sensitive ELISA method. Cells were incubated with the secretagogues angiotensin II, ACTH, and K(+), at various physiological concentrations with and without 1 microm deoxycorticosterone as additional substrate. In addition, RT-PCR was used to detect expression of the mRNA for the aldosterone synthase gene using a protocol developed by us that detects very low expression in subregions of the human brain. Our results failed to demonstrate mRNA for the aldosterone synthase gene or aldosterone biosynthesis in human endothelial cells.