Nitric Oxide Synthases in Various Normal Human Tissues: mRNA Sizes and Contents of NOS

초록

Abstract: Using the necropsy tissue samples (IRB approved) of sudden accidental death patients, differential expression levels of NOS mRNAs and proteins were determined in various brain regions and peripheral tissues. Two different sizes (~12 and ~11 kb) of nNOS mRNA were detected in tissue specific patterns. In the Western-blot analysis, however, at least 3 different nNOS bands were detected. Two different sized iNOS mRNAs (4.5 and 4.2 kb) were expressed constitutively at different levels in some brain regions and in peripheral tissues like ovary and small intestine. In some tissues, however, only a single band iNOS protein was observed. As with the iNOS mRNAs, two different sized eNOS mRNA (4.4 and 4.2 kb) were observed in almost all human tissues examined. Again, in the heart, placenta and spleen, only a single eNOS protein band was observed. These differen-tial expressions of NOS mRNAs and proteins are produced by alternative splicing and this may be associated with the diverse tissue specific roles of NO observed in vivo.