CRF-immunoreactive nerve fibers in the circumventricular organs of the monkey, Macaca fuscata

The occurrence of CRF (corticotropin-releasing factor)-immunoreactive nerve fibers in the circumventricular organs of adult male monkeys, Macaca fuscata, was studied on serially sectioned brains, by means of the peroxidase-antiperoxidase technique in combination with a highly specific and sensitive CRF antiserum. CRF-containing nerve fibers were found in high concentrations in the infundibulum and, in addition, in small numbers in the posterior lobe, organum vasculosum laminae terminalis, subfornical organ, and area postrema; they were missing in the pineal body and the subcommissural organ. The CRF-immunoreactive nerve fibers distributed in these organs were located in the proximity of the blood vessels.