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C J Lowenstein

Publications and source records attributed to C J Lowenstein.

60 records · Page 4Linked to original sources
PubMed1992

Cloned and expressed macrophage nitric oxide synthase contrasts with the brain enzyme.

Nitric oxide (NO) is a messenger molecule of macrophages, endothelial cells in blood vessels, and neurons. A neuronal form of NO synthase (NOS) has been previously cloned. We now report the molecular cloning of macrophage NOS. The macrophage enzyme displays 50% sequence identity to the neuronal enzyme. Like neuronal NOS, macrophage NOS has recognition sites for FAD, FMN, and NADPH and also has a consensus calmodulin binding site. Macrophage NOS mRNA is strikingly inducible; it is absent in quiescent macrophages or spleen but is prominent 2-6 hr after endotoxin treatment.

Amino Acid Oxidoreductases↗
PubMed1992

Nitric oxide: a physiologic mediator of penile erection.

Nitric oxide (NO) is a cytotoxic agent of macrophages, a messenger molecule of neurons, and a vasodilator produced by endothelial cells. NO synthase, the synthetic enzyme for NO, was localized to rat penile neurons innervating the corpora cavernosa and to neuronal plexuses in the adventitial layer of penile arteries. Small doses of NO synthase inhibitors abolished electrophysiologically induced penile erections. These results establish NO as a physiologic mediator of erectile function.

Amino Acid Oxidoreductases↗
PubMed1992

Cytokines and lipopolysaccharide induce nitric oxide synthase in cultured rat pulmonary artery smooth muscle.

In the current study, we describe cytokine and Escherichia coli lipopolysaccharide (LPS) induction of nitric oxide (NO) synthase mRNA levels in cultured smooth muscle from rat pulmonary artery (RPASM). Exposure of RPASM to interleukin-1 beta, interferon-gamma, or LPS alone did not significantly affect NO synthesis, as determined by nitrite concentrations in media. Exposure to tumor necrosis factor-alpha caused a modest (2x) increase in nitrite production. In contrast, exposure to a combination of the above three cytokines and LPS caused a large increase in NO synthesis. Exposure of RPASM to this combination caused an increase in mRNA levels of NO synthase (as described by Northern blot analysis with 32P-cDNA probe to an inducible form of NO synthase present in murine macrophages) that was apparent as early as 4 h. Expression of the induced gene product after exposure to the cytokine and LPS mixture was evident by significant increases in nitrite production at 12 h. Production of nitrite was completely abolished in the presence of NG-monomethyl-L-arginine (NMA), and this inhibition was reversible by the addition of excess L-arginine. NO synthase mRNA levels were not affected by NMA. The nitrite production induced by the combination of cytokines and LPS was abolished by pretreating cells with cycloheximide. These data indicate that a combination of cytokines and LPS affect expression of the gene for the inducible form of NO synthase in cultured RPASM.

Amino Acid Oxidoreductases↗