Long-term metabolic consequences of acute dioxin exposure differ between male and female mice

Abstract

SUMMARYExposure to environmental pollutants is consistently associated with increased diabetes risk in humans. In male mice, acute dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) exposure supresses insulin secretion. This study investigated the long-term effects of a single TCDD injection (20 µg/kg) on glucose metabolism and beta cell function in male and female mice. TCDD-exposed males displayed modest fasting hypoglycemia for ∼4 weeks post-injection, reduced fasting insulin levels for up to 6 weeks, increased insulin sensitivity, and decreased beta cell area. TCDD-exposed females also had long-term suppressed basal plasma insulin levels, and abnormal insulin secretion for up to 6 weeks. Unlike males, TCDD did not impact insulin sensitivity or beta cell area in females, but did cause transient glucose intolerance 4 weeks post-exposure. Our results show that a single exposure to dioxin can supress basal insulin levels long-term in both sexes, but effects on metabolism are sex-dependent.