The ontogeny of brain receptors for corticotropin-releasing factor and the development of their functional association with adenylate cyclase.

This study reports the ontogeny of corticotropin-releasing factor (CRF) receptor binding sites in rat brain, using both membrane binding assays and in vitro receptor autoradiography. CRF binding sites are evident by prenatal day 17, increase to 312% of their adult density by postnatal day 8, then decrease to reach adult values by day 21. Not only the density, but the distribution of CRF binding undergoes major modifications in development. CRF binding sites are most numerous in striatum prenatally, but postnatally, binding is more dense in the cortex, reaching the adult laminar distribution by postnatal day 14. Brain CRF receptors are linked to adenylate cyclase early in postnatal life. This contrasts with the later appearance of most of the guanine nucleotide stimulatory protein and catalytic subunit sites in the rat brain and suggests that CRF receptors may become functional earlier than several other brain receptors that are linked to adenylate cyclase.