H2s is a gasoneurotransmitter and is regulated by HO-1 through Nrf2. The other two gasoneurotransmitters are NO and CO and we suggest there may a similar mode of action between protection and poisoning from all three – regulated by HO-1. Bauer writes, “The protective effects of exogenous CO may strongly depend on the pathological condition, the mode, time point and duration of application, the administered concentration, and on the target tissue and cell. Differences in bioavailability of endogenous CO-production and exogenous CO supplementation might also provide an explanation for the lack of protective effects observed in some experimental and in clinical studies.” H2S may be comparable and as this author points out, more research is needed.


Bauer, I. and Pannen, B. (2009). Bench-to-bedside review: Carbon monoxide – from mitochondrial poisoning to therapeutic use. Critical Care, 13(4):220+.http://www.citeulike.org/user/HEIRS/article/5439821