A limiting factor to the clinical management of diabetes is iatrogenic hypoglycemia. With multiple hypoglycemic episodes, the collective neuroendocrine response that restores euglycemia is impaired. In our animal model of recurrent hypoglycemia (RH), neuroendocrine deficits are accompanied by a decrease in medial hypothalamic activation. Here we tested the hypothesis that the medial hypothalamus may exhibit unique changes in the expression of regulatory proteins in response to RH. Further, we addressed whether the alterations associated with RH include a form of neural plasticity or adaptation. We report that expression of the immediate early gene (IEG) FosB is increased in medial hypothalamic nuclei, anterior hypothalamus, and posterior paraventricular nucleus of the thalamus (THPVP) following RH. We identified the hypothalamic paraventricular nucleus (PVN), a key autonomic output site, among the regions expressing FosB. To identify the subtype(s) of neuronal populations that express FosB, we screened candidate neuropeptides of the PVN for coexpression using dual fluorescence immunohistochemistry. Among the neuropeptides analyzed (including oxytocin (OT), vasopressin (VP), thyrotropin releasing hormone (TRH), and corticotropin releasing factor (CRF)), FosB was only identified in CRF-positive neurons. Inhibitory gamma-amino-butyric-acid (GABA)-positive processes appear to impinge on these FosB-expressing neurons. Finally, we observed a significant decrease in the presynaptic marker synaptophysin (SYN) within the PVN of RH-treated versus saline-treated rats, suggesting that rapid alterations of synaptic morphology may occur in association with RH. Collectively, these data suggest that RH stress triggers cellular changes that support synaptic plasticity, in specific neuroanatomical sites, which may contribute to the development of HAAF.