Hale P M, Khoury S, Foster C M, Beitins I Z, Hopwood N J, Marshall J C, Kelch R P
Department of Pediatrics, University of Michigan Medical School, Ann Arbor 48109.
J Clin Endocrinol Metab. 1988 Apr;66(4):785-91. doi: 10.1210/jcem-66-4-785.
Gonadotropin secretion is pulsatile in prepubertal and early pubertal boys, and the onset of puberty is characterized by a sleep-associated rise in LH pulse amplitude. To determine whether an augmentation in LH pulse frequency as well as amplitude occurs at the onset of puberty, we studied gonadotropin secretion in 21 early to midpubertal boys. Blood samples were taken every 20 min (every 15 min in 4 boys) for LH determinations. A 2-fold increase in LH pulse frequency occurred during the nighttime sampling period (2200-0400 h) compared to that in the hours when the boys were awake (1000-2200 h). The maximum frequency (0.7 pulses/h) occurred between 2400 and 0200 h. The mean plasma LH concentration increased during the night from 2.3 +/- 0.2 (+/- SE) mIU/mL (2.3 +/- 0.2 IU/L) between 2000-2200 h to a maximum of 6.2 +/- 0.4 (6.2 +/- 0.4 IU/L) between 0200-0400 h. The mean plasma LH decreased to 5.5 +/- 0.4 mIU/mL (5.5 +/- 0.4 IU/L) between 0400-0600 h and to 4.2 +/- 0.5 (4.2 +/- 0.5 IU/L) between 0600-0800 h. Plasma testosterone rose during the night to a mean maximum value of 2.4 +/- 0.5 (+/- SE) ng/mL (8.3 +/- 1.7 nmol/L). This finding suggested that the rise in testosterone might play a role in decreasing LH secretion during the later hours of sleep (after 0400 h). To address this question and to study further the effects of testosterone in early puberty, we measured plasma LH concentrations every 10 min from 2000-0800 h in 8 early to mid-pubertal boys before and during short term testosterone administration. Saline or testosterone at a concentration of 9.33 micrograms/mL (32 mumol/L) was infused at a rate of 10 mL/h from 2100-1200 h to shift the nighttime testosterone rise 3 h earlier than would occur spontaneously. Blood samples were obtained every 10 min for LH and every 30 min for testosterone determinations from 2000-0800 h. Pituitary responsiveness was assessed by administering sequential doses of synthetic GnRH (25 and 250 ng/kg) at 1000 and 1200 h, respectively. The nighttime increase in LH pulse frequency and mean plasma LH concentration occurred between 2300 and 0200 h despite testosterone infusion. However, testosterone infusion was associated with significantly lower mean plasma LH concentrations from 0200-0800 h compared to those on the night of the saline infusion. Pituitary responsiveness to synthetic GnRH was unaltered by testosterone administration.(ABSTRACT TRUNCATED AT 400 WORDS)
在青春期前和青春期早期的男孩中，促性腺激素分泌呈脉冲式，青春期开始的特征是促黄体生成素（LH）脉冲幅度与睡眠相关的升高。为了确定在青春期开始时LH脉冲频率以及幅度是否增加，我们研究了21名青春期早期至中期男孩的促性腺激素分泌情况。每20分钟采集一次血样（4名男孩每15分钟采集一次）用于测定LH。与男孩清醒时（1000 - 2200时）相比，夜间采样期（2200 - 0400时）LH脉冲频率增加了2倍。最高频率（0.7次脉冲/小时）出现在2400至0200时之间。夜间血浆LH平均浓度从2000 - 2200时的2.3±0.2（±标准误）mIU/mL（2.3±0.2 IU/L）增加到0200 - 0400时的最高值6.2±0.4（6.2±0.4 IU/L）。0400 - 0600时血浆LH平均浓度降至5.5±0.4 mIU/mL（5.5±0.4 IU/L），0600 - 0800时降至4.2±0.5（4.2±0.5 IU/L）。夜间血浆睾酮升高至平均最大值2.4±0.5（±标准误）ng/mL（8.3±1.7 nmol/L）。这一发现表明，睾酮升高可能在睡眠后期（0400时之后）降低LH分泌中起作用。为了解决这个问题并进一步研究睾酮在青春期早期的作用，我们在8名青春期早期至中期男孩短期给予睾酮前后，于2000 - 0800时每10分钟测量一次血浆LH浓度。从2100 - 1200时以10 mL/h的速度输注生理盐水或浓度为9.33微克/毫升（32微摩尔/升）的睾酮，以使夜间睾酮升高比自然发生时间提前3小时。从2000 - 0800时每10分钟采集一次血样用于测定LH，每30分钟采集一次血样用于测定睾酮。分别在1000时和1200时给予连续剂量的合成促性腺激素释放激素（GnRH）（25和250 ng/kg）来评估垂体反应性。尽管输注了睾酮，但夜间LH脉冲频率和血浆LH平均浓度的增加仍发生在2300至0200时之间。然而，与输注生理盐水的夜间相比，输注睾酮后0200 - 0800时血浆LH平均浓度显著降低。给予睾酮后垂体对合成GnRH的反应性未改变。（摘要截短至400字）
