CORTICOTROPIN-RELEASING FACTOR (CRF) RECEPTORS IN INFANT RHESUS-MONKEY BRAIN AND PITUITARY-GLAND - BIOCHEMICAL-CHARACTERIZATION AND AUTORADIOGRAPHIC LOCALIZATION

A large body of data suggests that the corticotropin-releasing factor (CRF) system serves to coordinate the autonomic, endocrine, immune and behavioral aspects of the stress response. In rats, the distribution of CRF receptors in brain and pituitary has been well characterized, h owever, little information is available in primates. In this study, CR F receptors were characterized by radioligand binding and localized us ing autoradiography with [I-125]-oCRF in the pituitary gland and in di screte brain regions of 2-week-old, 12-week-old and adult rhesus monke ys. Autoradiographic localization studies in slide-mounted tissue sect ions in the 2- and 12-week-old monkeys demonstrated high CRF receptor densities in both anterior and intermediate lobes of the pituitary as well as in discrete regions of the brain. The distribution of CRF rece ptors in the anterior pituitary demonstrated a 'cluster-like' appearan ce reminiscent of corticotrope distribution. In contrast, receptors in the intermediate lobe were more uniformly distributed. No significant differences were evident in the pattern of localization or the number of CRF receptors in the pituitaries of 2- compared to 12-week-old ani mals. However, marked differences were observed in the dentate gyrus o f the hippocampus. Receptors in this region were absent in 1- to 2-wee k old animals but quite dense by 11-12 weeks of age. Conversely, in th e lateral and medial geniculate nuclei, high levels of CRF receptors w ere identified early in life that virtually disappeared by 11-12 weeks of age. Thus, there is considerable correspondence in the development of the CRF system between the rat and rhesus monkey and this presents further evidence for the functional role of this peptide in brain dev elopment.