GONADOTROPIN HORMONE-RELEASING HORMONE-INDUCED LUTEINIZING-HORMONE RESPONSES IN YOUNG AND OLD FEMALE C57BL/6J MICE
GONADOTROPIN HORMONE-RELEASING HORMONE-INDUCED LUTEINIZING-HORMONE RESPONSES IN YOUNG AND OLD FEMALE C57BL/6J MICE
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DOI：
10.3181/00379727-204-43651
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发表时间：
1993-11-01
影响因子：
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通讯作者：
MILLER, MM
中科院分区：
文献类型：
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作者：
JOSHI, D;LEKHTMAN, I;MILLER, MM
与年轻（6个月）雌性小鼠相比，雌激素诱导的促黄体生成激素（LH）激增在老年（24个月）雌性小鼠中明显减弱。为了测试这种减弱的LH反应是否是由于垂体对下丘脑促性腺激素释放激素（GnRH）的反应能力减弱，在年轻（5-6个月）、正常周期（n = 6）和老年（24个月）、非周期性恒定间情期（n = 6）C57 BL/6 J雌性小鼠中测量了垂体对外源性GnRH的反应。切除小鼠卵巢，雌激素处理7天。在第6天颈静脉插管后，在第7天以15分钟间隔采集连续血样，持续165分钟。在输注生理盐水或GnRH（5 μ g/5 μ l生理盐水/kg体重和15 μ g/15 μ l生理盐水/kg体重，间隔1小时）之前和之后获得的样品中测量血清LH。生理盐水给药动物在年轻（0.09 +/- 0.02 ng/ml基线）或老年（0.11 +/- 0.01 ng/ml基线）雌性动物中均未显示LH反应。然而，在年轻小鼠（0.3 +/- 0.04 ng/ml第一次激发，0.69 +/- 0.1 ng/ml第二次激发）和老年小鼠（0.78 +/- 0.1 ng/ml第一次激发，1.76 +/- 0.2 ng/ml第二次激发）中，每次GnRH激发均获得显著的LH释放。老年组LH反应显著高于青年组（P < 0.05，方差分析）。这些结果表明，老年雌性小鼠的垂体至少能够响应GnRH的外源性刺激的年轻。我们的结论是，改变垂体的能力，以响应GnRH是不太可能是一个因素，导致改变LH分泌随着年龄的C57 BL/6 J小鼠。
The estrogen-induced luteinizing hormone (LH) surge is markedly attenuated in old (24 months) female mice compared with young (6 months) females. To test whether or not this attenuated LH response is due to a diminished capacity of the pituitary to respond to hypothalamic gonadotropin hormone-releasing hormone (GnRH), the pituitary response to exogenous GnRH was measured in young (5-6 months), normally cycling (n = 6) and old (24 months), acyclic constant diestrus (n = 6) C57BL/6J female mice. Mice were ovariectomized and estrogen-treated for 7 days. After intrajugular catheterization on Day 6, serial blood samples were taken at 15-min intervals for 165 min on Day 7. Serum LH was measured in samples obtained before and after infusion of either saline or GnRH (5 mu g/5 mu l saline/kg body wt) and 15 mu g/15 mu l saline/kg body wt 1 hr apart). Saline-treated animals demonstrated no LH response in either young (0.09 +/- 0.02 ng/ml baseline) or old (0.11 +/- 0.01 ng/ml baseline) females. However, a significant release of LH was obtained in response to each challenge of GnRH in both young (0.3 +/- 0.04 ng/ml first challenge, 0.69 +/- 0.1 ng/ml second challenge) and old (0.78 +/- 0.1 ng/ml first challenge, 1.76 +/- 0.2 ng/ml second challenge) mice. The LH response in the aged group was significantly greater (P < 0.05, analysis of variance) than in the young group. These results show that pituitaries of old female mice were at least as capable of responding to exogenous stimulation by GnRH as those of young. We conclude that alteration in the capacity of the pituitary to respond to GnRH is not likely to be a factor contributing to altered LH secretion with age in C57BL/6J mice.