title: Physiological and biochemical effects of acute exposure of fish to hydrogen sulfide.
abstract: 1. Exposure of channel catfish to 0.5 mg/l H2S at 20 degrees C resulted in hyperpnea, followed by apnea, and finally respiratory arrest. 2. Catfish brain cytochrome oxidase activity was inhibited in vitro 18% by 10(-7) M H2S, 64% by 10(-6) M H2S, and 100% by 10(-4) M H2S. 3. When channel catfish were exposed to 0.1 mg/l H2S at 20 degrees C for 30 min, the cytochrome oxidase activity of the brain was inhibited 40% and that of the gill was inhibited 74%, while blood lactate rose from 11.6 to 38.1 mg/100 ml. 4. Catfish with nitrite-induced methemoglobinemia showed less inhibition of brain and gill cytochrome oxidase when exposed to hydrogen sulfide than did control fish. 5. Sulfide-inhibited brain cytochrome oxidase recovered from a 50% inhibition to control levels in channel catfish after 6 hr in freshwater at 10 degrees C. 6. Management practices are recommended which may help the commercial fish farmer alleviate the problem of the toxicity of sulfide to fish during harvest operations.
mesh_terms: D000818:Animals; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism / Q000502:physiology*; D006862:Hydrogen Sulfide / Q000633:toxicity*; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008708:Methemoglobinemia / Q000139:chemically induced; D009132:Muscles / Q000201:enzymology; D010108:Oxyhemoglobins / Q000378:metabolism
chemical_list: D007773:Lactates; D010108:Oxyhemoglobins; D019344:Lactic Acid; D003576:Electron Transport Complex IV; D006862:Hydrogen Sulfide