Adenylyl cyclase isoforms are differentially expressed in primary cultures of endothelial cells and whole tissue homogenates from various rat tissues.

The expression of five adenylyl cyclase isoforms (types II-VI) was studied with reverse transcription-polymerase chain reaction in whole tissue homogenates and in primary cultures of endothelial cells isolated from rat aorta, vena cava, heart, lung, adipose fat, brain, and adrenal medulla. It was found that: i) all endothelial cell types express all adenylyl cyclase isoforms studied, albeit at different levels depending on the tissue origin of the cells, and ii) the adenylyl cyclase isoform profile of isolated endothelial cells differs from that of homogenates of their parent tissues. Our data show a unique endothelial cell type specificity of AC isoform expression, which varies from that of the whole organ. These results support the idea that one of the factors mediating differential regulation of the cAMP cascade in EC in various locations within the vascular tree might be quantitative differences in the levels of AC isoforms expressed in each EC type.