SMART: Somatotrophics, Memory, and Aging Research Trial

Inclusion Criteria: * Able to give and understand informed consent * Able to communicate in English * No exclusionary criteria apply * Age between 55 and 90 years * Independent in their daily living abilities * Living at home with a reliable spouse, significant other or caregiver * Normal PSA (for men) or mammogram (for women) within one year of study entry The following inclusion criteria will be applied to identify potential MCI participants: * Memory complaint that can be corroborated by a study partner * Memory test scores meeting the diagnostic criteria for MCI * MMSE score greater than 20 The following inclusion criteria will be applied to identify potential normal control participants: * Cognitive testing does not indicate MCI * MMSE score greater than 28 Exclusion Criteria: * Use of medications known to affect the GHRH/GH/IGF-I axis, including transdermal estrogens (use of oral estrogens is not contraindicated) * Significant medical illness or organ failure, such as uncontrolled hypertension, diabetes, cardiac disease, cerebrovascular disease, chronic obstructive pulmonary disease, kidney and liver disease * Significant neurologic disease that might affect cognition, such as Alzheimer's disease, stroke, Parkinson's disease, multiple sclerosis, severe head injury with loss of consciousness for more than 30 minutes or with permanent neurologic sequelae * Personal or strong family history of cancer (especially colon, breast or melanoma) * Evidence for pituitary disease by history or physical examination * Symptoms or history of carpal tunnel or a positive Phalen's Test * Active arthritis * Significant current psychiatric illness, such as depression, schizophrenia or an Axis II diagnosis suggestive of an inability to successfully complete the study protocol * Current use of an anti-psychotic, anti-depressant, anti-convulsant, anti-coagulant, anxiolytic or sedative * Current or planned use of DHEA, testosterone or cognition-enhancing medication (e.g., cholinesterase inhibitors, memantine) * Weight greater than 150% ideal body weight * Tobacco use, excessive alcohol intake (more than 2 drinks per day), excessive caffeine intake (more than 4 cups of coffee per day) * Baseline IGF-I level greater than the mid-range for healthy young adults (250 ng/ml) * Meets NINCDS/ADRDA criteria for AD