Heroux J A, Grigoriadis D E, De Souza E B
Laboratory of Neurobiology, National Institute on Drug Abuse, Baltimore, MD 21224.
Brain Res. 1991 Feb 22;542(1):155-8. doi: 10.1016/0006-8993(91)91011-o.
Corticotropin-releasing factor (CRF) receptors were measured in discrete areas of brain and in anterior pituitary of 4-, 12-, 18-, and 24-month-old male Fischer rats. No significant age-related alterations in [125I]ovine CRF binding were observed in the olfactory bulb, cerebral cortex, hippocampus, brainstem, and cerebellum; there was a trend for CRF binding to decrease in the striatum as a consequence of aging. Significant age-related decreases were observed in 125I-ovine CRF binding in the anterior pituitary and hypothalamus with maximal reductions of 60 and 27%, respectively. Saturation analysis in the anterior pituitary indicated an age-related reduction in the density of CRF receptors (i.e. Bmax) without an alteration in the affinity (i.e. Kd) of CRF for its binding site. Northern analysis of proopiomelanocortin (POMC) mRNA in the anterior pituitary indicated no significant differences in the levels of POMC mRNA between 4- and 24-month-old rats. These and other data suggest that the age-related decrease in anterior pituitary CRF receptors may be due to hypersecretion of hypothalamic CRF rather than a loss of corticotropes in the anterior pituitary.
在4个月、12个月、18个月和24个月大的雄性Fischer大鼠的脑离散区域和垂体前叶中测量促肾上腺皮质激素释放因子（CRF）受体。在嗅球、大脑皮层、海马体、脑干和小脑中未观察到与年龄相关的[125I]羊CRF结合的显著变化；随着年龄增长，纹状体中CRF结合有下降趋势。在垂体前叶和下丘脑观察到与年龄相关的125I-羊CRF结合显著下降，最大降幅分别为60%和27%。垂体前叶的饱和分析表明，CRF受体密度（即Bmax）与年龄相关降低，而CRF与其结合位点的亲和力（即Kd）没有改变。垂体前叶中阿黑皮素原（POMC）mRNA的Northern分析表明，4个月和24个月大的大鼠之间POMC mRNA水平无显著差异。这些数据和其他数据表明，垂体前叶CRF受体与年龄相关的下降可能是由于下丘脑CRF分泌过多，而不是垂体前叶促肾上腺皮质激素细胞的丧失。
