Abstract
We have generated transgenic rats expressing enhanced green fluorescent protein (EGFP) under the control of estrogen receptor α (ERα) gene promoter 0/B. In the adults of this trait, fluorescence of EGFP was observed in the brain, particularly in the preoptic area (POA)-bed nucleus of the stria terminalis (BNST), amygdala, midbrain central gray, hippocampus and cortex. In the POA-BNST and the medial amygdala, 70% of EGFP-labeled cells were ERα immunoreactive suggesting the usefulness of the transgenic rats for physiological studies on estrogen signaling in the adult brain. Here we report the developmental expression of EGFP during fetal and neonatal life. Sporadic EGFP fluorescence were detected on embryonic day 15; the expression gradually increased and the adult pattern of distribution was established in early postnatal period. ERα/EGFP double-labeled cells were more numerous in the neonates than adults. Only in the neonates, double-labeled cells were detected in the midline thalamus. EGFP labels were observed clearly in fibers in the fornix and anterior commissure, and surrounded the ventromedial hypothalamic nucleus and suprachiasmatic nucleus without penetrating into the nuclear core. EGFP was also expressed in the sexually dimorphic nucleus of the POA. These results suggest that the action of ERα gene promoter 0/B is regulated developmentally in the rat brain. [Jpn J Physiol 55 Suppl:S212 (2005)]
