Abstract
We have generated transgenic rats expressing enhanced green fluorescent protein (EGFP) under the control of the estrogen receptor α (ERα) promoter 0/B (Hamada et al., 2003). Here we report the pattern of the EGFP expression in the rat brain and other tissues in detail. Fluorescence of EGFP was observed extensively in the brain, particularly in the cortex, hippocampus, preoptic area, dorsal hypothalamic area, amygdala and midbrain central gray. A few, weakly fluorescent cells appeared in the ventromedial hypothalamic nucleus. Many EGFP-labeled cells were ERα immunoreactive in the medial preoptic nucleus, the bed nucleus of the stria terminalis and the medial amygdala. Unexpectedly, a few EGFP-labeled cells were immunoreactive to ERα antibody in the other areas of the brain. In the hippocampus, a subpopulation of fluorescent interneurons expressed GAD65/67. In the rostral midbrain central gray, fluorescent cells were found in the dorsal part whereas they were in the ventral part in the caudal portion of this structure. EGFP expressions were prominent on embryonic day 15; the expression gradually decreased as they developed. In the pituitary, EGFP fluorescent cells were also observed. These results suggest that the action of rat ERα promoter 0/B is regulated specifically in subregions of the brain, in different tissues or during the ontogeny. The transgenic rats would be useful for physiological studies on the role of estrogen signaling in the brain and other tissues. [Jpn J Physiol 54 Suppl:S223 (2004)]
