CHANGES IN THE NUMBER OF ESTROGEN RECEPTOR ALPHA AND BETA IMMUNOREACTIVE CELLS ON POAAHA DURING THE ESTROUS CYCLE OF THE RAT

Abstract

We have previously shown that the expression of the mRNA for estrogen receptor alpha (ERalpha mRNA) and beta (ERbeta mRNA) in the POA-AHA is asymmetric and varies during the estrous cycle. The aim of present study was to evaluate the number of estrogen receptor immunoreactive (ir) cells (ERalpha and ERbeta) in both sides of POAAHA at 09:00, 13:00 and 17:00 hours of each phase of the estrous cycle The lowest number of ERalpha-ir cells on both sides of the POA-AHA was observed at 13:00 hours on diestrus-2, proestrus and estrus, while the highest number was measured at 09:00 and 17:00 hours on diestrus 2 and estrus. At 09:00 hours of diestrus 1, the number of ERalpha-ir cells in the right side of the POA-AHA was significantly higher than in the left one (2256±163 vs. 1431±133, p<0.05 Student t test). The highest number of ERbeta-ir cells on both sides of the POA-AHA was observed at 13:00 hours on proestrus and estrus. Present results in the number of positive cells do not follow the changes in the ERalpha and beta mRNA expression observed during the estrous cycle. The results suggest that ERalpha-ir and ERbeta-ir number of positive cells change in a circadian and opposite way during the estrous cycle rat. Supported by PAPPIT IN201005 (poster)