Endocrine, liver-derived IGF-I is of importance for spatial learning and memory in old mice

IGF-I is a neuroprotective hormone, and neurodegenerative disorders, including Alzheimer’s disease, have been associated with decreased serum IGF-I concentration. In this study, IGF-I production was inactivated in the liver of adult mice (LI-IGF-I / ), resulting in an approximately 80–85% reduction of circulating IGF-I concentrations. In young (6-month-old) mice there was no difference between the LI-IGF-I / and the control mice in spatial learning and memory as measured using the Morris water maze test. In old (aged 15 and 18 months) LI-IGF-I /