Abstract
Numerous epidemiological studies have identified a positive association of exposure to the endocrine-disrupting pesticide dichlorodiphenyltrichloroethane (DDT) and its primary metabolite dichlorodiphenyldichloroethylene (DDE) with the risk of obesity. Of particular concern is the persistent metabolic dysfunction resulting from early life DDT and DDE exposures, evidenced as obesity, glucose intolerance, dyslipidemia, and impaired thermogenesis in adult rodents. However, little is known about the developmental timing and etiopathogenesis of this long-term DDT-related metabolic phenotype. This study aimed to address these knowledge gaps by evaluating endocrine phenotypes and thermogenic parameters at two postnatal (P) time points, P0 and P12, in C57BL/6J mice. Dams were orally gavaged with p,p’-DDT (1.7 mg/kg body weight [BW]), p,p’-DDE (1.31 mg/kg BW), or organic olive oil (vehicle) daily from gestational day (GD) 11.5-P0 or P5. Infrared analysis was then performed during a cold challenge. We further attempted to rescue the cold-challenged P12 mice by administering the β3-adrenergic receptor (AR)-agonist CL316,243 (CL), a direct stimulator of brown adipose (BAT) thermogenesis. At P0, area under the curve analysis revealed higher body temperatures in both males and females exposed to DDE compared to controls during the 9 min cold challenge. In addition, DDE-exposed females lost body heat at a significantly faster rate than sex-matched controls over the 9 min cold challenge. This occurred without any treatment-related differences in resting glucose, suprascapular BAT weight, or body weight for either sex at P0. To assess BAT-autonomous response to β3-AR stimulation during a cold challenge, P12 mice were exposed to the pharmacological β3-AR agonist, or PBS control in a 2x2 exposure design and suprascapular BAT temperature was evaluated via infrared analysis of the suprascapular surface at 10 min intervals. Blood glucose, BAT weight, and BW remained equivocal across all P12 treatment groups. However, BAT temperature was significantly decreased 10 min after cold- challenge in female P12 mice with perinatal DDE-exposure when compared to sex- and perinatal treatment-matched controls. This DDE effect among P12 female mice was rescued by CL. These data suggest that thermogenic dysfunction consequent to perinatal DDE exposure is detectable during postnatal development, well before the emergence of endocrine phenotypes. The CL rescue of the BAT thermogenic impairments observed after perinatal DDE exposure are consistent with DDE toxicities upstream in the β3-AR nerve circuitry. Additionally, the data highlight the emergence of an early postnatal sex divergence in DDE-related thermogenic dysfunction. We speculate that the effects of DDE on suprascapular BAT heat production result from prenatal alterations in sympathetic circuitry.
Contrasting recruitment of skin‐associated adipose depots during cold challenge of mouse and human
