NOS1 and hemorrhage: The most pronounced inhibition of hematopoesis, as well as granulopenia, thrombocytopenia, aplasia, and hemorrhage observed in 18 days pt are accompanied with the enhancedlevels of the NOS substrate and metabolites (L-arginine, RNS and L-citrulline) due to up-regulation of iNOS in marrow and blood formed elements (erythrocyte were not sudied).