title: Renal function in the freshwater rainbow trout (Oncorhynchus mykiss) following acute and prolonged exposure to waterborne nickel.
abstract: Renal function was investigated in adult rainbow trout following acute and prolonged exposure to waterborne Ni in moderately hard Lake Ontario water (approximately 140 mgL(-1) as CaCO3). Fish were exposed for 36 days to a sublethal concentration of 442 microg Ni L(-1), followed by 96 h of exposure to 12,850 microg Ni L(-1) (approximately 33% of the 96 h LC50). Prolonged exposure markedly affected only the renal handling of Ni, with no substantial effect on the plasma concentration, urinary excretion rate (UER) or clearance ratio (CR) of Na+, Cl-, K+, Ca2+, Mg2+, inorganic phosphate (P(i)), glucose, lactate, total ammonia (T(amm)), protein and free amino acids (FAA). Glomerular filtration rate (GFR) was reduced by 75% over 96 h of acute Ni challenge in both fish previously exposed to Ni and naive fish, with no significant change in urine flow rate (UFR), suggesting a substantial reduction in water reabsorption to maintain urine flow and water balance. Renal Mg2+ handling was specifically impaired by acute Ni challenge, leading to a significantly increased UER(Mg2+) and significantly decreased plasma [Mg2+] only in naive fish. Previously-exposed fish were well-protected against Ni-induced Mg2+ antagonism, indicating true acclimation to Ni. Only in naive, acutely challenged fish was there an increased UER of titratable acidity (TA-HCO3), net acidic equivalents, P(i), T(amm) and K+. Again, all of these parameters were well-conserved in previously-exposed fish during acute Ni exposure, strongly suggesting that prolonged, sublethal exposure protected against acute Ni-induced respiratory toxicity.
authors.affiliation: Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ont., Canada L8S 4K1. michanderic@yahoo.com
authors.forename: Eric F
authors.initials: EF
authors.lastname: Pane
authors.forename: Carol
authors.initials: C
authors.lastname: Bucking
authors.forename: Monika
authors.initials: M
authors.lastname: Patel
authors.forename: Chris M
authors.initials: CM
authors.lastname: Wood
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001774:Blood Chemical Analysis; D001794:Blood Pressure; D004781:Environmental Exposure; D005618:Fresh Water / Q000032:analysis; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006339:Heart Rate; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D009532:Nickel / Q000633:toxicity*; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D009864:Ontario; D010710:Phosphates / Q000378:metabolism; D013054:Spectrophotometry, Atomic; D014556:Urine / Q000737:chemistry / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000596:Amino Acids; D008670:Metals; D010710:Phosphates; D014874:Water Pollutants, Chemical; D019344:Lactic Acid; D000641:Ammonia; D009532:Nickel; D005947:Glucose