Metabolic and osmoregulatory responses of the sea bass Lates calcarifer to nitrite exposure

• Published in: Environmental toxicology and water quality 1997, Vol.12 (3), p.257-264
• Main Authors: Woo, N.Y.S. (The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.), Chiu, S.F
• Format: Article
• Language: English
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADENINE NUCLEOTIDES; adenylate energy charge; Agnatha. Pisces; AGUA DE MAR; ANIMAL TISSUES; Animal, plant and microbial ecology; Applied ecology; ATPASA; ATPASE; AZOTE; BAR; Biological and medical sciences; BLOOD SERUM; CHEMICAL COMPOSITION; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; EAU DE MER; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; LATES CALCARIFER; LUBINA; Marine; METABOLISM; METABOLISME; METABOLISMO; METABOLITE; METABOLITES; METABOLITOS; NITRITE; NITRITE NITROGEN; NITRITES; NITRITOS; NITROGEN; NITROGENO; NUCLEOTIDE; NUCLEOTIDES; NUCLEOTIDOS; OSMOREGULACION; OSMOREGULATION; SEA BASS; SEA WATER; SERUM SANGUIN; SUERO SANGUINEO; TEJIDOS ANIMALES; TISSU ANIMAL; TOXICIDAD; TOXICITE; TOXICITY
• ISSN: 1053-4725; 1098-2256
• DOI: 10.1002/(SICI)1098-2256(1997)12:3<257::AID-TOX9>3.0.CO;2-7

Sea bass (Lates calcarifer) were exposed to seawater containing 0, 30, 50, or 80 mg L-1 NO2-N for 4 days, and changes in metabolite levels and enzyme activities were assessed. Distinct signs of osmoregulatory dysfunction were evident in nitrite-exposed fish as serum Na+ and Cl levels were elevated and branchial Na+-K+-ATPase activity was significantly reduced. Serum lactate and protein levels were significantly elevated and lowered respectively only at the highest nitrite level (80 mg L-1 NO2-N). Significantly increased serum ammonia and urea and decreased serum glucose and liver glycogen levels were evident also at lower nitrite levels. Liver water, liver protein and lactate, brain and muscle lactate, and muscle water content were unaffected. In the liver, significant decreases were observed for the activities of glycogen phosphorylase a, glutamate-oxaloacetate transaminase, and glutamate dehydrogenase, but the activities of lactate dehydrogenase, isocitrate dehydrogenase, glucose-6-phosphatase, glutamatepyruvate transaminase, and glucose-6-phosphate dehydrogenase were unaffected. While ATP, ADP, and AMP levels were all lowered in nitrite-exposed fish, the adenylate energy charge was maintained at fairly constant level. By producing ammonia via the degradation of AMP to IMP, stabilization of the adenylate energy charge can be achieved. It is postulated that this event probably represents an adaptive strategy employed by the sea bass to counteract nitrite toxicity