AGE-RELATED REDUCTION IN PITUITARY CORTICOTROPIN-RELEASING HORMONE RECEPTORS IN 2 RAT STRAINS

被引:41
作者
TIZABI, Y
AGUILERA, G
GILAD, GM
机构
[1] NICHHD, DEV ENDOCRINOL BRANCH, BETHESDA, MD 20892 USA
[2] ST ELIZABETH HOSP, NIMH, CTR NEUROSCI, NEUROPSYCHIAT BRANCH, WASHINGTON, DC 20032 USA
关键词
AGING; HYPOTHALAMIC-PITUITARY ADRENAL AXIS; CRH RECEPTOR; ACTH; RAT STRAINS;
D O I
10.1016/0197-4580(92)90034-U
中图分类号
R592 [老年病学]; C [社会科学总论];
学科分类号
03 ; 0303 ; 100203 ;
摘要
Open field behavior and age-related changes in anterior pituitary corticotropin-releasing hormone (CRH) receptors, as well as plasma ACTH levels, were measured in two inbred rat strains. The strains utilized were Wistar Kyoto (WKY) and Brown-Norway (BN), the former characterized by shorter life-span and hyper-reactivity to stressors as compared to the latter. Behaviorally, WKY rats showed hyper-responsivity to a novel environment as indicated by their delay in entering the open field, increased grooming, reduced rearing, and reduced locomotion. These strain-dependent behavioral differences were not affected by aging. The binding capacity of CRH receptors was similar in both strains and Bmax values were decreased (25-27%) with aging, with no changes in Kd values. In contrast, plasma ACTH levels were 67% higher in WKY than in BN rats but did not change with aging. Thus, despite pituitary CRH receptor down regulation, plasma ACTH levels following decapitation were sustained during aging. This suggests the presence of some compensatory factors in the hypothalamic-pituitary axis regulation which sustain ACTH response during aging. Furthermore, the findings indicate that higher plasma ACTH levels and hyper-reactivity to a novel environment are inversely correlated with longevity in the rat.
引用
收藏
页码:227 / 230
页数:4
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