2,3,7,8-Tetrachlorodibenzo-p-dioxin (
TCDD), an
endocrine disruptor, causes reproductive and developmental toxic effects in pups following maternal exposure in a number of animal models. Our previous studies have demonstrated that
TCDD imprints sexual immaturity by suppressing the expression of fetal
pituitary gonadotropins, the regulators of gonadal steroidogenesis. In the present study, we discovered that all
TCDD-produced damage to fetal production of
pituitary gonadotropins as well as testicular steroidogenesis can be repaired by co-treating pregnant rats with α-
lipoic acid (LA), an obligate co-factor for intermediary metabolism including energy production. While LA also acts as an
anti-oxidant, other
anti-oxidants; i.e.,
ascorbic acid,
butylated hydroxyanisole and
edaravone, failed to exhibit any beneficial effects. Neither
wasting syndrome nor
CYP1A1 induction in the fetal brain caused through the activation of
aryl hydrocarbon receptor (AhR) could be attenuated by LA. These lines of evidence suggest that oxidative stress makes only a minor contribution to the
TCDD-induced disorder of fetal steroidogenesis, and LA has a restorative effect by targeting on mechanism(s) other than AhR activation. Following a metabolomic analysis, it was found that
TCDD caused a more marked change in the hypothalamus, a pituitary regulator, than in the pituitary itself. Although the components of the tricarboxylic acid cycle and the
ATP content of the fetal hypothalamus were significantly changed by
TCDD, all these changes were again rectified by exogenous LA. We also provided evidence that the fetal hypothalamic content of endogenous LA is significantly reduced following maternal exposure to
TCDD. Thus, the data obtained strongly suggest that
TCDD reduces the expression of fetal
pituitary gonadotropins to imprint sexual immaturity or disturb development by suppressing the level of LA, one of the key players serving energy production.