Cholinesterases in blood plasma and tissues of rats treated with n-hexane or with its neurotoxic metabolite 2,5-hexanedione.
Adult male rats were subjected to 4 weeks' respiratory treatment with n-hexane (5000 ppm, 16h/day, 6 days/week); motor conduction velocity was significantly decreased in tail nerves at all weekly intervals and did not approach normal values in the 4 weeks following interruption of treatment. Plasma acetylcholinesterase (AChE) levels were significantly increased at all weekly intervals during treatment (25-40%); 2 weeks after the end of treatment they had returned to baseline. Oral treatment with 2,5-hexanedione (HD) (1% in drinking water) caused a similar increase in plasma levels; this increase was statistically significant also when compared with pair-fed (PF) control rats. A sucrose density gradient analysis showed only one peak of AChE activity at approximately 10 S (as in normal plasma). The levels of butyrylcholinesterase were unaltered in plasma of both n-hexane-and HD-treated rats. Both the fast-contracting EDL and the slow-contracting soleus muscles lost weight in HD-treated rats with respect to free-fed (AL) and PF controls. AChE levels responded differently to HD treatment in the two muscle types: in EDL total extracts, AChE activity increased considerably with respect to AL controls (+ 70%, p less than 0.001), while the levels of the 16 S and 4 S molecular forms were unaltered. The increased levels of AChE found in plasma of rats intoxicated with n-hexane or with its metabolite HD may originate from muscle and correspond to an increased secretion of this molecular form.
Istituto Superiore di Sanità, Rome, Italy.
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Bastone
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Frontali
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Mallozzi
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Sbraccia
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Settimi
D000818:Animals; D002499:Centrifugation, Density Gradient; D002802:Cholinesterases / Q000032:analysis* / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D006586:Hexanes / Q000633:toxicity*; D006588:Hexanones / Q000633:toxicity*; D007659:Ketones / Q000633:toxicity*; D008099:Liver / Q000201:enzymology; D008297:Male; D008991:Monitoring, Physiologic; D009043:Motor Activity / Q000187:drug effects; D009132:Muscles / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects
D006586:Hexanes; D006588:Hexanones; D007659:Ketones; C026385:n-hexane; C011269:2,5-hexanedione; D002802:Cholinesterases