Oxytocin selectively increases ERα mRNA in the neonatal hypothalamus and hippocampus of female prairie voles

During neonatal development exogenous oxytocin increases ERα immunoreactivity in the hypothalamus of female prairie voles. The purpose of this study was to determine if the increase in ERα is associated with an increase in ERα mRNA expression and to determine if the effect is specific to ER subtype or if oxytocin also influences ERβ mRNA expression. On the day of birth female prairie vole pups were treated with oxytocin, an oxytocin antagonist, or saline. Brains were collected and RT-PCR was used to determine the effect of treatment on ER mRNA production in the hypothalamus, hippocampus, and cortex. Within 2 h of treatment oxytocin significantly increased ERα mRNA expression in the hypothalamus and hippocampus, but not the cortex, while inhibiting the effects of endogenous oxytocin reduced the expression of ERα mRNA in the hippocampus. Neonatal treatment did not affect the expression of ERβmRNA. The results demonstrate that the effects of oxytocin treatment are region and ER subtype specific and that during the neonatal period oxytocin can affect the expression of ERα by altering message production. The regional specific changes in ERα mRNA expression in females are consistent with studies examining the behavioral and physiological effects of neonatal manipulation of oxytocin in females.