Urban R J
Department of Internal Medicine, University of Texas Medical Branch, Galveston.
Endocrinol Metab Clin North Am. 1992 Dec;21(4):921-31.
Many changes in the neuroendocrine axis occur with healthy normal aging in humans. Women cease ovarian follicle maturation and menstrual cycles entering the estrogen-deficient state termed menopause. Although not without risk, estrogen and progesterone replacement in postmenopausal women has been shown to ameliorate the complications of lowered estradiol concentrations, such as hot flushes and osteoporsis, while improving the risk of cardiovascular complications. Aging men have lowered serum free and total testosterone concentrations and may experience a less well defined symptom complex termed andropause. Both signs and symptoms of thyroid disease and interpretation of thyroid function tests are difficult in aging humans. Specifically, TSH secretion is diminished in aging so that suppressed serum TSH concentrations are indicative of but not specific for hyperthyroidism. Cortisol secretion is not altered in aging, although serum concentrations of DHEA-S are lower. Prolactin concentrations are increased in both men and women, with the increase being more pronounced in men. The clinical significance of this increase has not yet been determined. Finally, elderly humans are more likely to develop difficulties with fluid and electrolyte balance. Although some alterations in AVP secretion have been shown in the elderly, plasma concentrations are similar in young and elderly subjects. Other mechanisms, such as decreased glomerular filtration rate and a decreased sensitivity of the thirst mechanism in response to hypertonicity, may be important contributors to fluid and electrolyte imbalances.
随着人类健康正常衰老，神经内分泌轴会发生许多变化。女性停止卵巢卵泡成熟和月经周期，进入雌激素缺乏状态，即更年期。虽然并非没有风险，但已证明绝经后女性补充雌激素和孕激素可改善雌二醇浓度降低的并发症，如潮热和骨质疏松症，同时降低心血管并发症的风险。老年男性血清游离睾酮和总睾酮浓度降低，可能会经历一种定义不太明确的症状群，称为男性更年期。在老年人中，甲状腺疾病的体征和症状以及甲状腺功能测试的解读都很困难。具体而言，衰老过程中促甲状腺激素（TSH）分泌减少，因此血清TSH浓度被抑制表明可能患有甲状腺功能亢进，但不具有特异性。衰老过程中皮质醇分泌没有改变，尽管硫酸脱氢表雄酮（DHEA-S）的血清浓度较低。男性和女性的催乳素浓度均升高，男性升高更为明显。这种升高的临床意义尚未确定。最后，老年人更容易出现体液和电解质平衡方面的问题。虽然已证明老年人的抗利尿激素（AVP）分泌有一些变化，但年轻和老年受试者的血浆浓度相似。其他机制，如肾小球滤过率降低和口渴机制对高渗反应的敏感性降低，可能是导致体液和电解质失衡的重要因素。
