Albers N, Bettendorf M, Herrmann H, Kaplan S L, Grumbach M M
Department of Pediatrics, University of California, San Francisco 94143-0106.
Endocrinology. 1993 Feb;132(2):701-9. doi: 10.1210/endo.132.2.8425489.
To analyze the secretion patterns of LH, FSH, GH, and PRL in the late gestational sheep fetus in vivo, we measured simultaneous plasma levels of these hormones during a period of frequent sampling under basal conditions (samples every 15 min for 5 h) in 17 chronically catheterized sheep fetuses. To calculate mean plasma levels and areas under the curve, we analyzed hormone pulses and coincident pulse patterns to assess interactions between the release of these pituitary hormones. Mean plasma levels for all fetuses were: LH, 0.8 +/- 0.2 ng/ml (mean +/- SEM); FSH, 4.6 +/- 0.7 ng/ml; GH, 136.6 +/- 16.5 ng/ml; and PRL, 40.5 +/- 10.3 ng/ml. Pulse analysis detected 20 LH pulses during 5100 min of total sampling time, which gave a mean interpulse interval of 255.0 min. For GH, 37 pulses were detected; the mean interpulse interval was 129.7 min. Twenty PRL pulses yielded a mean interpulse interval of 225.0 min. FSH pulses could not be analyzed due to the long half-life of this hormone, but hormone level fluctuations were screened for maxima. A new method was developed to detect an interaction between hormone pulses. The probability of the simultaneous occurrence of hormone pulses was calculated and compared with the rate of coincidences found in the experiments. Analysis of copulsatile release of LH, GH, and PRL revealed 11 GH pulses coinciding with the LH pulses (P = 0.0020). An interaction between the pulsatile release of LH and GH can, therefore, be assumed. There was also a significant interaction between GH and PRL. Seven PRL pulses preceded the GH pulses by 15 min (P = 0.0014). In contrast, no significant copulsatile release could be observed between LH and PRL; 95.5% of LH pulses were accompanied by a maximum FSH level, suggesting an interaction between LH and FSH secretion. In summary, we show that LH, GH, and PRL (and possibly FSH) are secreted in a pulsatile fashion in the ovine fetus. Furthermore, the pulsatile releases of LH, FSH, and GH as well as GH and PRL are temporarily coupled, as demonstrated by a significant number of coincident pulses between LH/GH and GH/PRL and a high number of FSH hormone maxima concomitant with LH pulses.
为了分析妊娠晚期绵羊胎儿体内促黄体生成素（LH）、促卵泡生成素（FSH）、生长激素（GH）和催乳素（PRL）的分泌模式，我们在17只长期插管的绵羊胎儿的基础条件下（每15分钟采样一次，共5小时）频繁采样期间，同步测量了这些激素的血浆水平。为了计算平均血浆水平和曲线下面积，我们分析了激素脉冲和同步脉冲模式，以评估这些垂体激素释放之间的相互作用。所有胎儿的平均血浆水平为：LH，0.8±0.2 ng/ml（平均值±标准误）；FSH，4.6±0.7 ng/ml；GH，136.6±16.5 ng/ml；PRL，40.5±10.3 ng/ml。脉冲分析在总采样时间5100分钟内检测到20个LH脉冲，平均脉冲间隔为255.0分钟。对于GH，检测到37个脉冲；平均脉冲间隔为129.7分钟。20个PRL脉冲产生的平均脉冲间隔为225.0分钟。由于该激素半衰期长，无法分析FSH脉冲，但筛选了激素水平波动的最大值。开发了一种新方法来检测激素脉冲之间的相互作用。计算了激素脉冲同时出现的概率，并与实验中发现的同步率进行了比较。对LH、GH和PRL的共脉冲释放分析显示，有11个GH脉冲与LH脉冲同步（P = 0.0020）。因此，可以假定LH和GH的脉冲释放之间存在相互作用。GH和PRL之间也存在显著的相互作用。七个PRL脉冲在GH脉冲前15分钟出现（P = 0.0014）。相比之下，未观察到LH和PRL之间有显著的共脉冲释放；95.5%的LH脉冲伴有FSH水平最大值，表明LH和FSH分泌之间存在相互作用。总之，我们表明LH、GH和PRL（可能还有FSH）在绵羊胎儿中以脉冲方式分泌。此外，LH、FSH和GH以及GH和PRL的脉冲释放是暂时耦合的，LH/GH和GH/PRL之间大量同步脉冲以及大量FSH激素最大值与LH脉冲同时出现证明了这一点。
