Regulatory mechanisms of growth hormone secretion are sexually dimorphic
Regulatory mechanisms of growth hormone secretion are sexually dimorphic
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DOI：
10.1172/jci2908
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发表时间：
1998-07-01
影响因子：
15.9
通讯作者：
Barkan, AL
中科院分区：
文献类型：
--
作者：
Jaffe, CA;Ocampo-Lim, B;Barkan, AL
生长激素（GH）分泌的性别二型性模式在确定大鼠性别特异性生长和代谢模式中具有重要意义。人类的生长激素分泌是否也是两性异形的，以及控制这种潜在差异的神经内分泌机制还没有完全确定。我们比较了年轻男性和女性在基线状态下和连续静脉输注重组人胰岛素样生长因子I（rhIGF-I）期间的脉冲式GH分泌曲线。在基线研究期间，男性夜间GH脉冲较大，其余时间脉冲相对较小，相反，女性GH分泌更连续，GH脉冲更频繁，大小更均匀。输注rhIGF-I（10 μ g/kg/h）可有效抑制男性自发和生长激素释放激素（GHRH）诱导的GH分泌。然而，在女性中，rhIGF-I对GH脉冲分泌的影响较小，并且不抑制GH对GHRH的反应。这些数据表明，在人类生长激素分泌的调节机制中存在性二态性。女性对GHRH的GH反应的持续性表明IGF-I的负反馈可能部分通过抑制下丘脑GHRH来表达。
Sexually dimorphic growth hormone (GH) secretory pattern is important in the determination of gender-specific patterns of growth and metabolism in rats. Whether GH secretion in humans is also sexually dimorphic and the neuroendocrine mechanisms governing this potential difference are not fully established. We have compared pulsatile GH secretion profiles in young men and women in the baseline state and during a continuous intravenous infusion of recombinant human insulin-like growth factor I (rhIGF-I), During the baseline study, men had large nocturnal GH pulses and relatively small pulses during the rest of the day, In contrast, women had more continuous GH secretion and more frequent GH pulses that were of more uniform size. The infusion of rhIGF-I (10 mu g/kg/h) potently suppressed both spontaneous and growth hormone-releasing hormone (GHRH)-induced GH secretion in men. In women, however, rhIGF-I had less effect on pulsatile GH secretion and did not suppress the GH response to GHRH. These data demonstrate the existence of sexual dimorphism in the regulatory mechanisms involved in GH secretion in humans. The persistence of GH responses to GHRH in women suggests that negative feedback by IGF-I might be expressed, in part, through suppression of hypothalamic GHRH.