Journal
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Volume 305, Issue 6, Pages R592-R603Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpregu.00421.2012
Keywords
oxygen sensing; gasotransmitter; mitochondria
Categories
Funding
- National Science Foundation [IOS 1051627]
- Division Of Integrative Organismal Systems
- Direct For Biological Sciences [1051627] Funding Source: National Science Foundation
Ask authors/readers for more resources
H2S derived from organic thiol metabolism has been proposed serve as an oxygen sensor in a variety of systems because of its susceptibility to oxidation and its ability to mimic hypoxic responses in numerous oxygen-sensing tissues. Thiosulfate, an intermediate in oxidative H2S metabolism can alternatively be reduced and regenerate H2S. We propose that this contributes to the H2S-mediated oxygen-sensing mechanism. H2S formation from thiosulfate in buffers and in a variety of mammalian tissues and in lamprey dorsal aorta was examined in real time using a polarographic H2S sensor. Inferences of intracellular H2S production were made by examining hypoxic pulmonary vasoconstriction (HPV) in bovine pulmonary arteries under conditions in which increased H2S production would be expected and in mouse and rat aortas, where reducing conditions should mediate vasorelaxation. In Krebs-Henseleit (mammalian) and Cortland (lamprey) buffers, H2S was generated from thiosulfate in the presence of the exogenous reducing agent, DTT, or the endogenous reductant dihydrolipoic acid (DHLA). Both the magnitude and rate of H2S production were greatly increased by these reductants in the presence of tissue, with the most notable effects occurring in the liver. H2S production was only observed when tissues were hypoxic; exposure to room air, or injecting oxygen inhibited H2S production and resulted in net H2S consumption. Both DTT and DHLA augmented HPV, and DHLA dose-dependently relaxed precontracted mouse and rat aortas. These results indicate that thiosulfate can contribute to H2S signaling under hypoxic conditions and that this is not only a ready source of H2S production but also serves as a means of recycling sulfur and thereby conserving biologically relevant thiols.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available