Corticotropin releasing factor administered into the ventricular CSF stimulates the pituitary-adrenal axis.

Ovine corticotropin releasing factor (CRF) given intracerebroventricularly to rhesus monkeys at doses of 0.1-1 microgram/kg activates the pituitary-adrenal axis. The increases of plasma cortisol concentrations after intraventricular injection of CRF were similar to those observed after intravenous administration of this releasing factor and occurred without elevation of plasma concentrations of CRF, measured by radioimmunoassay. Thus, the cerebrospinal fluid (CSF) can serve as a conduit for delivery of CRF to the pituitary gland.