The choroid plexuses, which lie in the ventricles of the brain, are the major producers of the cerebrospinal fluid (CSF) which bathes the mammalian central nervous system. These tissues are critical to the maintenance of the fluid environment which surrounds and cushions the brain and spinal cord. Significant numbers of receptors for insulin and the insulin-like growth factors (IGF) have been localized on choroid plexus cells, but resulting biological actions have not been demonstrated. The planned investigations will examine the effects of insulin and IGF on the choroid plexus ion transport mechanisms which are integral to CSF formation. Comparisons will be made between the mature and infant rat; choroid plexus transport capability and CSF production are not fully developed in infant rats, and specific IGF receptor density varies with age. Dr. Parmelee's research will establish a link between growth factor-receptor coupling and choroid plexus physiology and will identify developmental differences in insulin-like growth factor action.
