High turnover rates for hydrogen sulfide allow for rapid regulation of its tissue concentrations.
OBJECTIVE
Hydrogen sulfide (H(2)S) is a signaling molecule, which influences many physiological processes. While H(2)S is produced and degraded in many cell types, the kinetics of its turnover in different tissues has not been reported. In this study, we have assessed the rates of H(2)S production in murine liver, kidney, and brain homogenates at pH 7.4, 37°C, and at physiologically relevant cysteine concentrations. We have also studied the kinetics of H(2)S clearance by liver, kidney, and brain homogenates under aerobic and anaerobic conditions.


RESULTS
We find that the rate of H(2)S production by these tissue homogenates is considerably higher than background rates observed in the absence of exogenous substrates. An exponential decay of H(2)S with time is observed and, as expected, is significantly faster under aerobic conditions. The half-life for H(2)S under aerobic conditions is 2.0, 2.8, and 10.0 min with liver, kidney, and brain homogenate, respectively. Western-blot analysis of the sulfur dioxygenase, ETHE1, involved in H(2)S catabolism, demonstrates higher steady-state protein levels in liver and kidney versus brain.


METHODS
By combining experimental and simulation approaches, we demonstrate high rates of tissue H(2)S turnover and provide estimates of steady-state H(2)S levels.


CONCLUSIONS
Our study reveals that tissues maintain a high metabolic flux of sulfur through H(2)S, providing a rationale for how H(2)S levels can be rapidly regulated.
Biological Chemistry Department, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, USA.
Victor
V
Vitvitsky
Omer
O
Kabil
Ruma
R
Banerjee
D000818:Animals; D001921:Brain / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C
D006862:Hydrogen Sulfide