Harman S M, Tsitouras P D, Costa P T, Blackman M R
J Clin Endocrinol Metab. 1982 Mar;54(3):547-51. doi: 10.1210/jcem-54-3-547.
Although basal serum LH and FSH levels have been shown to increase with age in men, there is evidence that aging may impair pituitary gonadotropin secretion to some extent. We have measured serum LH and FSH before and after the iv injection of 100 micrograms LRH in 69 healthy men, divided into 3 age groups: A (25-49 yr; n = 24), B (50-69 yr; n = 23), and C (70-89 yr; n = 22). We have previously demonstrated these men to have unaltered serum androgens and estrogens over the entire age range. Only log-transformed measures were analyzed in order to equalize variance among groups. Because we found increasing age to be associated with significant rises in basal levels of LH and FSH, and because the basal level affects the magnitude of response, we used repeated measures analysis of variance to compare LRH peak responses with basal gonadotropin levels. The presence of a significant interaction term would indicate an effect of age on response beyond that expected from the effect of basal level alone. The mean LRH responses (log peak--log basal) decreased, with significant interaction terms for both LH (P = 0.001) and FSH (P less than 0.0001) responses. This means that the function relating basal to peak gonadotropin concentrations changed significantly with age. Peak LH responses in the youngest group (A) occurred equally as often 15 and 30 min after LRH injection, but in the oldest group (C) there were no 15 min peaks, and 40% of the peak values occurred at 60 min (P less than 0.01). FSH peaks were equally distributed at 30, 60, and 120 min in all 3 groups. Total testicular volumes did not decrease significantly with age. We conclude that there is a small but statistically significant tendency for LH and FSH responses to LRH to be both diminished and delayed in healthy aging men. The mechanisms responsible for this apparent pituitary gonadotropic hypofunction remain to be clarified.
尽管已有研究表明男性基础血清促黄体生成素（LH）和促卵泡生成素（FSH）水平会随年龄增长而升高，但有证据显示衰老可能在一定程度上损害垂体促性腺激素的分泌。我们对69名健康男性进行了静脉注射100微克促性腺激素释放激素（LRH）前后血清LH和FSH的测量，这些男性被分为3个年龄组：A组（25 - 49岁；n = 24）、B组（50 - 69岁；n = 23）和C组（70 - 89岁；n = 22）。我们之前已证明这些男性在整个年龄范围内血清雄激素和雌激素水平未发生改变。为使各组方差均衡，仅对经对数转换后的测量值进行分析。由于我们发现年龄增长与LH和FSH基础水平的显著升高相关，且基础水平会影响反应幅度，因此我们采用重复测量方差分析来比较LRH峰值反应与基础促性腺激素水平。显著交互项的存在表明年龄对反应的影响超出了仅由基础水平影响所预期的范围。平均LRH反应（对数峰值 - 对数基础值）下降，LH反应（P = 0.001）和FSH反应（P < 0.0001）均有显著交互项。这意味着基础促性腺激素浓度与峰值之间的函数关系随年龄显著变化。最年轻组（A组）在LRH注射后15分钟和30分钟出现LH峰值反应的频率相同，但最年长组（C组）在15分钟时未出现峰值，40%的峰值出现在60分钟（P < 0.01）。FSH峰值在所有3组中均在30分钟、60分钟和120分钟时均匀分布。总睾丸体积并未随年龄显著减小。我们得出结论，在健康老年男性中，LH和FSH对LRH的反应存在虽小但具有统计学意义的减弱和延迟趋势。导致这种明显垂体促性腺功能减退的机制仍有待阐明。
