NOS1 and pulmonary hypertension: Hypoxia-induced pulmonary hypertension is deteriorated in the triple n/i/eNOSs−/− mice, and to a lesser extent, in the eNOS−/− mice, as compared with the WT mice, and hypoxia-induced pulmonary hypertension is also aggravated in the WT mice transplanted with triple n/i/eNOSs−/− bone marrow as compared with those with WT bone marrow, suggesting a protective role of the NOS system, specifically in bone marrow cells, in pulmonary hypertension19.