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Effect of temperature on the inhibition of rat brain synaptosomal ATPases by DDT and its structural analogs
Author(s) -
Chetty Sreeramulu C.,
Aldous Charles N.,
Desaiah Durisala
Publication year - 1984
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.2550040407
Subject(s) - atpase , chemistry , pharmacology , toxicology , microbiology and biotechnology , biophysics , biochemistry , biology , enzyme
In vitro effects of DDT and its isomers or metabolites were studied on Na + ‐K + ‐ATPase and oligomycinsensitive (OS) Mg ++ ‐ATPase activities at 17, 27 and 37°C in rat brain synaptosomes. Dicofol and methoxychlor were found to be more effective inhibitors of Na + ‐K + ‐ATPase and OS Mg ++ ‐ATPase than DDT, DDD and DDE. Inhibition of OS Mg ++ ‐ATPase by the compounds tested (except DDE) was found to be greater at 17°C than at higher temperatures (17>27>37°C), suggesting a negative temperature correlation trend. Na + ‐K + ‐ATPase was less sensitive to these compounds when compared with OS Mg ++ ‐ATPase and the inhibition was greater at higher temperatures (37>27>17°C), suggesting a positive temperature correlation trend. Other DDT isomers and metabolites showed variable effects on Na + ‐K + ‐ATPase and OS Mg ++ ‐ATPases. DDD, but not DDE, inhibited both enzyme activities and the inhibition was independent of temperature. No significant differences were observed in the inhibitory potencies of the various DDT, DDD or DDE ring substitutes studied. The present data indicate that DDT, dicofol and methoxychlor were more effective inhibitors of OS Mg ++ ‐ATPase than Na + ‐K + ‐ATPase and that the inhibition of the former enzyme had a negative temperature dependence, a feature which parallels toxicity results in insects.