Four nonvolatile nerve agent surrogates, 4-nitrophenyl ethyl dimethylphosphoramidate (NEDPA, a tabun surrogate), 4-nitrophenyl ethyl methylphosphonate (NEMP, a VX surrogate), and two sarin surrogates, phthalimidyl isopropyl methylphosphonate (PIMP) and 4-nitrophenyl isopropyl methylphosphonate (NIMP), were synthesized and tested as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. These surrogates were designed to phosphorylate cholinesterases with the same moiety as their respective nerve agents, making them highly relevant for the study of cholinesterase reactivators. Surrogates were characterized by liquid chromatography-mass spectrometry and nuclear magnetic resonance. NEMP, PIMP, and NIMP were potent inhibitors of rat brain, skeletal muscle, diaphragm, and serum AChE as well as human erythrocyte AChE and serum BuChE in vitro. PIMP was determined to degrade quickly in aqueous solution, making it useful for in vitro assays only, and NEDPA was not a potent inhibitor of AChE or BuChE in vitro; therefore, these two surrogates were not tested in subsequent in vivo studies. Sublethal dosages (yielding about 80% brain AChE inhibition) were determined for both the stable sarin surrogate, NIMP (0.325 mg/kg ip), and the VX surrogate, NEMP (0.4 mg/kg ip), in adult male rats. Time course studies indicated the time to peak brain AChE inhibition for both NIMP and NEMP to be 1 h postexposure. Both surrogates yielded severe cholinergic signs. These dosages did not require the addition of atropine to prevent lethality, and the rate of AChE aging was slow, making these surrogates useful for reactivation studies both in vitro and in vivo. The surrogates synthesized in this study are potent yet safer to test than nerve agents and are useful tools for initial screening of nerve agent oxime therapeutics.

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Diabetes mellitus is a highly prevalent metabolic disease affecting 29.1 million people or 9.3% of the population of the United States. The most prevalent form of diabetes is type 2 diabetes (T2D) which comprises 90-95% of all reported cases of diabetes. While the exact cause of T2D remains an enigma, known risk factors include age, weight, sedentary lifestyle, poor dietary habits, and genetic predisposition. However, these risk factors can not sufficiently explain the increasing prevalence of T2D. Recently, environmental exposures have been explored as potential risk factors. Indeed, epidemiological and limited empirical studies have revealed elevated serum concentrations of certain persistent organic pollutants (POPs), including the bioaccumulative metabolite of p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), are positively correlated with increased T2D prevalence. The goal of the present study is to determine if chronic exposure to DDE promotes T2D in a widely used in vivo model, the high saturated fat-fed mouse. Male C57BL/6H mice were exposed to DDE (2.0mg/kg) or vehicle (corn oil; 1ml/kg) via gavage for 5 consecutive days, then every 7 days for the duration of the study. One week following the 5 day consecutive DDE dosing, animals were placed on either a low fat (10%kcal from lard) or high fat (45%kcal from lard) diet (HFD) for 13 weeks. Chronic exposure to DDE promoted fasting hyperglycemia after 4 and 8 weeks on the HFD diet and normalized fasting blood glucose levels at week 13. This DDE-mediated decrease in fasting hyperglycemia was preceded by improved glucose tolerance at week 12. In addition to normalizing fasting hyperglycemia at the end of high fat feeding, DDE exposure decreased HFD-induced fasting hyperinsulinemia, homeostasis model assessment of insulin resistance (HOMA-IR) values, and hepatic steatosis. Therefore, based on the current data, chronic DDE exposure appears to have a biphasic effect on HFD-induced hyperglycemia in the male C57BL/6H mouse characterized by elevated fasting blood glucose at weeks 4 and 8 of HFD intake followed by normoglycemia upon sacrifice. In addition, chronic DDE exposure reduced HFD-induced hepatic steatosis upon sacrifice. These results indicate chronic exposure to DDE can directly affect systemic glucose and hepatic lipid metabolism and that these effects can be diet dependent.

Approximately 8.3% of the United States (U.S.) population have either diagnosed or undiagnosed diabetes mellitus. Out of all the cases of diabetes mellitus, approximately 90–95% of these cases are type 2 diabetes mellitus (T2D). Although the exact cause of T2D remains elusive, predisposing factors include age, weight, poor diet, and a sedentary lifestyle. Until recently the association between exposure to environmental contaminants and the occurrence of diabetes had been unexplored. However, recent epidemiological studies have revealed that elevated serum concentrations of certain persistent organic pollutants (POPs), especially organochlorine pesticides, are positively associated with increased prevalence of T2D and insulin resistance. The current study seeks to investigate if this association is causative or coincidental. Male C57BL/6H mice were exposed to DDE (2.0 mg/kg or 0.4 mg/kg) or vehicle (corn oil; 1 ml/kg) for five days via oral gavage; fasting blood glucose, glucose tolerance, and insulin challenge tests were performed following a seven day resting period. Exposure to DDE caused significant hyperglycemia compared to vehicle and this hyperglycemic effect persisted for up to 21 days following cessation of DDE administration. Intraperitoneal glucose tolerance tests and phosphorylation of Akt in the liver, skeletal muscle, and adipose tissue following insulin challenge were comparable between vehicle and DDE treated animals. To determine the direct effect of exposure to DDE on glucose uptake, in vitro glucose uptake assays following DDE exposure were performed in L6 myotubules and 3T3-L1 adipocytes. In summary, subacute exposure to DDE does produce fasting hyperglycemia, but this fasting hyperglycemia does not appear to be mediated by insulin resistance. Thus, the current study reveals that subacute exposure to DDE does alter systemic glucose homeostasis and may be a contributing factor to the development of hyperglycemia associated with diabetes.