Influence of the characteristics of pulses of gonadotrophin releasing hormone on the dynamics of luteinizing hormone release from perifused sheep pituitary cells.
Influence of the characteristics of pulses of gonadotrophin releasing hormone on the dynamics of luteinizing hormone release from perifused sheep pituitary cells.
复制标题
促性腺激素释放激素脉冲特征对灌注羊垂体细胞黄体生成激素释放动力学的影响。
作者：
R. P. McIntosh;J. McIntosh
本文研究了不同频率、宽度和幅度的促性腺激素释放激素（GnRH）脉冲对垂体前叶细胞释放LH的影响。将分散在Sephadex中的绵羊细胞用培养基灌注10 h，并用不同的GnRH恒定脉冲模式刺激。通过放射免疫测定流出物组分来测量LH释放的时间。对细胞施加持续时间为每8分钟2分钟至每128分钟16分钟、浓度为1.7 pmol/l至250 nmol/l的GnRH脉冲以及连续刺激。比较相同细胞制剂样品之间LH释放模式的差异，以证明不同GnRH刺激方案的影响。结果表明：（1）GnRH刺激频率对LH释放的性质有重要影响（脉冲之间的时间短于约16分钟减少LH输出并导致反应的更快脱敏），（2）GnRH输入的脉宽是重要的（脉冲的上升沿产生的LH输出每单位的GnRH输入比持续应用GnRH在一个脉冲和更宽的脉冲（3）在5-10 nmol GnRH/l脉冲幅度的阈值以上，对分散细胞LH输出或脱敏率的进一步影响很小。这些发现加强了GnRH脉冲的上升沿是LH释放的主要刺激物的假设。
The effects were studied of varying the frequency, width and amplitude of pulses of gonadotrophin releasing hormone (GnRH) on the release of LH from anterior pituitary cells. Dispersed sheep cells supported in Sephadex were perifused with medium for 10 h and stimulated with different constant pulse patterns of GnRH. The timing of release of LH was measured by radioimmunoassay of the effluent fractions. Pulses of GnRH ranging in duration from 2 min every 8 min to 16 min every 128 min, and in concentration from 1.7 pmol/l to 250 nmol/l were applied to the cells, as well as continuous stimulation. Comparisons of differences between LH release patterns among samples of the same preparation of cells were used to demonstrate the effects of different GnRH stimulatory regimes. It was concluded that (1) the frequency of GnRH stimulation was important to the nature of LH release (periods shorter than about 16 min between pulses reduced LH output and caused faster desensitization of response), (2) the pulse width of GnRH input was important (the rising edge of the pulse produced greater LH output per unit of GnRH input than did continued application of GnRH within a pulse and wider pulses combined with shorter periods reduced LH output) and (3) over a threshold value of 5-10 nmol GnRH/l pulse amplitude had little further influence on LH output or rate of desensitization in dispersed cells. These findings reinforce the hypothesis that the rising edge of the GnRH pulse is the major stimulant to LH release.