Endothelium-derived relaxing factor (EDRF) has profound effects on the renal vasculature, the glomerular mesangium, and also affects renal salt excretion. EDRF stimulates guanylyl cyclases, which are thought to be heterodimers comprised of alpha and beta subunits. Two alpha and two beta isoforms have been identified thus far. However, the molecular composition of in vivo guanylyl cyclase-linked...

Two enzymes, soluble guanylyl cyclase and cytochrome c oxidase, have been shown to be exquisitely sensitive to nitric oxide (NO) at low physiological concentrations. Activation of the soluble guanylyl cyclase by endogenous NO and the consequent increase in the second messenger cyclic GMP are now known to control a variety of biological functions. Cytochrome c oxidase, the terminal enzyme of the...

To the Editor roles of guanylyl cyclases must be viewed carefully. The reports [8,9] cited by Dr. Herring, et al. gave evidence We thank Dr. Herring et al. for their comments on our against the endothelial NO synthase hypothesis and NO in paper. In our recent report [1] we proposed that the muscarinic inhibition of I . Such experiments could not postjunctional source of cardiomyocyte cGMP, from...

OBJECTIVE Nitric oxide (NO) has been shown to induce apoptosis in cardiomyocytes under normoxic conditions. The ability of NO to induce apoptosis after ischemia-reperfusion, a situation of increased NO release in vivo, has not been investigated. The present study was undertaken to characterize the pathway of induction of apoptosis by NO and the influence of ischemia on this pathway in cardiomyo...

Guanylyl cyclase-activating proteins are EF-hand Ca(2+)-binding proteins that belong to the calmodulin superfamily. They are involved in the regulation of photoreceptor membrane-associated guanylyl cyclases that produce cGMP, a second messenger of vertebrate vision. Here, we investigated changes in GCAP1 structure using mutagenesis, chemical modifications, and spectroscopic methods. Two Cys res...

Heat-stable toxins (STs) produced by enterotoxigenic bacteria cause endemic and traveler's diarrhea by binding to and activating the intestinal receptor guanylyl cyclase C (GC-C). Advances in understanding the biology of GC-C have extended ST from a diarrheagenic peptide to a novel therapeutic agent. Here, we summarize the physiological and pathophysiological role of GC-C in fluid-electrolyte r...