A Tale of Two Hormones: Role of Leptin and Insulin in Hippocampal Synaptic Function

It is well documented that the endocrine hormones, leptin and insulin provide signals to specific hypothalamic brain regions to regulate energy balance. However, the past decade of research has not only revealed the widespread ex- pression of insulin and leptin receptors in the CNS, but has also identified numerous additional functions of these hor- mones in the brain. In particular, there is growing evidence that these hormones markedly influence hippocampal excita- tory synaptic transmission as well as hippocampal synaptic plasticity. More recent studies have also identified links be- tween dysregulation of leptin and insulin systems and the development of neurodegenerative disorders such as Alz- heimer's disease. Here we review the recent evidence supporting a role for these hormones in modulating hippocampal synaptic function in health and disease.