Effects of Adrenalectomy and Dexamethasone Administration on the Level of Prepro-Corticotropin-Releasing Factor Messenger Ribonucleic Acid (mRNA) in the Hypothalamus and Adrenocorticotropin/β-Lipotropin Precursor mRNA in the Pituitary in Rats*

摘要: RNA blot hybridization analysis with cloned rat CRF precursor (prepro-CRF) cDNA as a probe showed that prepro-CRF mRNA existed in hypothalamic and extrahypothalamic brain tissue, whereas it was undetectable the pituitary adrenal. To study effect of glucocorticoid on level hypothalmus ACTH/beta-lipotropin (beta LPH) pituitary, effects adrenalectomy dexamethasone administration were studied rats. Adrenalectomy markedly raised coding for ACTH/beta LPH anterior but not neurointermediate lobe. Hypothalamic pre-pro-CRF increased only to 152% control value, 7 days after adrenalectomy. The (200 micrograms/day days) started immediately lowered 19% intact hypothalamus decreased 102%. These results suggest glucocorticoids exert their feedback at gene expression both neurons corticotropes. Although possibility insensitive might blunt change could be ruled out, is also possible dominant.