Glycogen synthase kinase-3ß/ß-catenin signaling in the rat hypothalamus during the estrous cycle

During the estrous cycle, a remodeling of synapses on somas and dendritic spines occurs in the rat hypothalamic arcuate nucleus. The synaptic remodeling is known to be induced by estradiol, but the molecular mechanisms involved still have not been fully clarified. beta-Catenin is known to regulate synaptic plasticity, so we have assessed possible modifications of beta-catenin in the rat mediobasal hypothalamus during the estrous cycle. Our findings indicate that beta-catenin expression is increased during proestrus and estrus in comparison with diestrus day. This increase was accompanied by an enhanced phosphorylation of Akt in Ser473 and of glycogen synthase kinase-3 beta (GSK3 beta) in Ser9. Also, the association of beta-catenin with the synaptic protein PSD95 was increased during these same stages of the estrous cycle, whereas the levels of synapsin I were significantly decreased in proestrus. These findings suggest that Akt/GSK3 beta/beta-catenin signaling is involved in the synaptic modifications that occur in the basal hypothalamus during the estrous cycle. (C) 2012 Wiley Periodicals, Inc.