Chest
Today's Practice of Cardiopulmonary MedicineMetabolic Functions of the Lung: Of What Clinical Relevance?
Section snippets
Modulation of Angiotensin-Converting Enzyme
Figure 3 diagrams the two protease pathways that share angiotensin-converting enzyme (ACE). The renin-angiotensin system relies on the activity of ACE for elaboration of its key effector component, AII In response to volume or depressor stimuli and to beta-adrenergic stimulation, the kidneys release active renin. This protease catalyzes the release of the relatively inert decapeptide AI from angioten-sinogen. In a single passage through the lungs, AI is converted by ACE into AII, one of the
Depression of Pulmonary Uptake of 5-Hydroxytryptamine (Serotonin) and Norepinephrine
Five-hydroxytryptamine (5-HT) and norepinephrine (NE) are biologically active amines found in a wide variety of mammalian cells.1 Five-hydroxytryptamine is a potent platelet aggregatory agent and contributes to the functioning of the central nervous system. Norepinephrine is the neurotransmitter of most sympathetic postganglionic fibers and is a major hormone of the adrenal medulla. In addition, 5-HT and NE are potent vasopressors for systemic and pulmonary vascular beds, and it is noteworthy
Conclusion
Evidence is mounting that the metabolic functions of the lung are important in health and disease, but there have been few studies in humans. Extrapolating data derived from studies of the lungs of experimental animals to those of humans is not yet justified. Close correlations in time between biochemical changes and physiologic changes in humans and experimental animals are important, but they are not sufficient. Use of selected agonists and antagonists is necessary not only to provide greater
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