Mice with global or conditional, EC-restricted GC-A deletion develop PH even under normoxic conditions. Right ventricular (RV) systolic pressure is increased.This is accompanied by RV hypertrophy and dysfunction, enhanced muscularization of small pulmonary arteries and arteriolar rarefaction. At difference, deletion of GC-A in SMC did not result in PH. Because mice with EC-restricted ablation of GC-A (EC GC-A KO) develop PH, a microarray analysis was performed to identify differentially expressed genes. Precapillary pulmonary arteries (21-87 µm diameter) were dissected by Laser microdissection, RNA was isolated and transcribed into cDNA and applied to Mouse 430_2 Affimetrix chips. The mRNA expression of 34 genes was up- and of 13 genes was downregulated in precapillary pulmonary arteries of EC-GC-A-KO mice. The top ten overexpressed mRNAs were Epac2 (3.6 times), adenosine deaminase, tRNA-specific 2 (3.1 times), UBX domain protein 7 (3.0 times), ring finger protein 128 (2.8 times), DAZ interacting protein 3 zinc finger (2.8 times), UDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 5 (2.7 times), LEM domain containing 3 (2.6 times), retinol dehydrogenase 10 (2.2 times), glypican 4 (2.2 times) and splicing factor proline/glutamine rich (2.2 times). The top ten downregulated mRNAs were charged multivesicular body protein 4C (-3.2 times), family with sequence similarity 199, X-linked (-3.1 times), transient receptor potential cation channel, subfamily M, member 7 (-2.8 times), pecanex homolog (Drosophila) (-2.7 times), serine/arginine-rich splicing factor 18 (-2.6 times), zinc finger and BTB domain containing 1 (-2.5 times), importin 5 (-2.4 times), adenomatosis polyposis coli (-2.3 times), myogenic factor 5 (-2.3 times) and solute carrier family 35 member B3 (-2.2 times).