DDVP (dichlorvos) detoxification by binding and interactions with DDT, dieldrin, and malaoxon

Area of Science:

• Toxicology
• Biochemistry
• Environmental Health

Background:

• Tissue carboxylesterases are implicated in the detoxification of several organophosphates.
• Understanding organophosphate detoxification mechanisms is crucial for assessing toxicity and developing interventions.

Purpose of the Study:

• To investigate the role of carboxylesterase binding in the detoxification of dichlorvos (DDVP), malaoxon, and paraoxon in mice.
• To examine the effects of DDT and dieldrin pretreatment on organophosphate binding and toxicity.

Main Methods:

• In vitro inactivation assays using mouse liver preparations.
• Organophosphate binding studies following pretreatment with triorthotolyl phosphate (TOTP), DDT, dieldrin, or DDVP.
• Assessment of organophosphate toxicity and anticholinesterase activity.

Main Results:

• DDVP, malaoxon, and paraoxon were inactivated by mouse liver carboxylesterases in vitro.
• Dieldrin enhanced malaoxon and paraoxon binding, while DDT enhanced DDVP binding.
• DDVP pretreatment inhibited malaoxon binding and potentiated its toxicity, indicating DDVP interferes with malaoxon detoxification.

Conclusions:

• Carboxylesterase binding is not a significant detoxification pathway for DDVP in mice.
• DDVP can inhibit the detoxification of other organophosphates like malaoxon, increasing their toxicity.