CORTICOTROPIN-RELEASING FACTOR UP-REGULATES ITS OWN RECEPTOR MESSENGER-RNA IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS

We investigated the role of CRF in regulating receptor expression in t he paraventricular nucleus (PVN). First, to clarify the effect of exog enously administered CRF, 1 mu g of ovine CRF was injected into rat la teral ventricle and changes in concentration of the CRF type 1 recepto r (CRF1-R) and CRF mRNA in the PVN were semiquantified after in situ h ybridization. Second, we determined the effect of stress, as a stimula nt of endogenous CRF secretion, on mRNA accumulation. While CRF1-R mRN A expression was low to be undetectable in the PVN of controls, both i ntracerebroventricular administration of CRF and restraint significant ly increased CRF1-R and CRF signals in the parvocellular PVN. Thus CRF may modulate CRF production and release from the PVN, by regulating C RF1-R expression.