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Plasma leucine aminonaphthylamidase as an indicator of acute sublethal toxicant stress in rainbow trout
Author(s) -
Dixon D. G.,
Hill C. E. A.,
Kempe E. J.,
Hodson P. V.,
Kaiser K. L. E.
Publication year - 1985
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620040610
Subject(s) - rainbow trout , toxicant , chemistry , intraperitoneal injection , toxicity , endocrinology , medicine , toxicology , zoology , fish <actinopterygii> , biology , fishery , organic chemistry
Leucine aminonaphthylamidase (LAN) is a lysosomal enzyme that appears in blood plasma after cell death. Levels of plasma LAN (PLAN) were assayed to quantify toxicant stress in rainbow trout in a series of experiments. Blood samples were taken from groups of fish weighing 80 to 100 g following intraperitoneal (i.p.) and/or waterborne exposure to p ‐methylphenol (PMP) or carbon tetrachloride (CCl 4 ). The duration of postinjection holding significantly affected PLAN activity in control and PMP‐dosed rainbow trout; the largest increases occurred after 96 h. There were significant correlations between dose and PLAN activity after both PMP and CCl 4 injection. PLAN levels of fish injected with PMP at doses of 0.075 to 0.75 of the 96‐h i.p. LD50 were elevated by 27 to 63% relative to controls 96 h after injection. PLAN levels of fish injected with CCl 4 at doses of 0.18 to 0.79 of the i.p. LD50 were elevated by 38 to 135% relative to controls 48 h after injection. Exposure of fish to a waterborne concentration of 0.028 mM PMP (0.41 96‐h LC50) significantly increased PLAN activity after 48, 96 and 192 h; activities increased by 38 to 87% relative to controls. Elevated PLAN activity was strongly correlated with decreased plasma protein levels. The temperature and duration of plasma storage affected the measured PLAN activity of control and PMP‐dosed rainbow trout. While diet modified PLAN activity, the gender of immature fish had no effect. Hepatic lesions visible by light microscope were observed with waterborne PMP exposure; parenchymatous edema was closely associated with increased liver somatic index. There were, however, no visible lesions or changes in the index associated with the pulse i.p. doses of PMP and CCl 4 . In these cases, biochemical lesions preceded any evidence of histopathology.