Hypothalamic LHRH in aging rats: effects of ovariectomy and steroid replacement.
Hypothalamic LHRH in aging rats: effects of ovariectomy and steroid replacement.
复制标题
衰老大鼠的下丘脑 LHRH：卵巢切除术和类固醇替代的影响。
DOI：
10.1016/0197-4580(85)90009-0
复制
发表时间：
1985
影响因子：
4.2
通讯作者：
Bridges,RS
中科院分区：
文献类型：
--
作者：
Rubin,BS;Elkind-Hirsch,K;Bridges,RS
采用RIA法测定了中青年雌性大鼠在不同内分泌条件下下丘脑LHRH的变化。在切除卵巢的年轻人和MA受试者的下丘脑内侧基底区和下丘脑前视区片段中，LHRH含量与类固醇诱导的促性腺激素激增相关的时间变化进行了比较。LHRH含量也比较了来自两个年龄组的卵巢切除，未经治疗的受试者。最后，将MA恒发情雌鼠与年轻雌鼠在发情前早晨的LHRH含量进行比较。在所有情况下，雄性雄激素雌性的两个脑区LHRH水平与年轻雌性相似，或显著高于年轻雌性，但类固醇诱导的激增和阉割诱导的促性腺激素高分泌在衰老雌性中都明显减弱。由于研究证实了MA大鼠垂体对LHRH的反应性，数据表明下丘脑LHRH不能到达垂体。相反，在MA受试者中测量到的高水平下丘脑LHRH可能代表LHRH神经元中肽的积累，这是由于与年龄相关的释放损伤。
Hypothalamic LHRH was measured by RIA in young and middle-aged (MA) female rats in several endocrine conditions. Temporal alterations in LHRH content associated with the steroid induced gonadotropin surge were compared in medial basal hypothalamic and anterior hypothalamicpreoptic area fragments of ovariectomized young and MA subjects. LHRH content was also compared in ovariectomized, untreated subjects from the two age groups. Finally, LHRH content in MA constant estrous females was compared with content in young females on the morning of proestrus. In all conditions, LHRH levels in both brain regions of MA females were similar to, or significantly elevated above levels measured in young females, yet both the steroid induced surge and the castration induced hypersecretion of gonadotropins were markedly attenuated in aging females. Because studies have verified the responsiveness of the pituitary of MA rats to LHRH, the data suggest that adequate amounts of hypothalamic LHRH do not reach the pituitary. Rather, high levels of hypothalamic LHRH measured in MA subjects may represent accumulation of the peptide in LHRH neurons due to an age-related impairment in release.