Gevers E, Pincus S M, Robinson I C, Veldhuis J D
Department of Pediatric Endocrinology, University Hospital Leiden, The Netherlands.
Am J Physiol. 1998 Feb;274(2):R437-44. doi: 10.1152/ajpregu.1998.274.2.R437.
Male- and female-specific modes of episodic growth hormone (GH) release are presumptively imposed by sex steroid hormones, and, although typically evident visually, are vividly distinguished quantitatively via a regularity statistic, approximate entropy (ApEn), in both the rat and human. GH secretory patterns may determine GH-stimulated growth and specific hepatic and muscle gene expression in the rat. Consequently, it is important to discern mechanisms that underlie their regulation. Here we have examined the impact of prepubertal gonadal suppression (at 4 wk of age) via surgical or pharmacological [gonadotropin-releasing hormone (GnRH) agonist] intervention on the regularity (ApEn) of GH release in male and female rats (at 10-11 wk of age) sampled at 10-min intervals for 10 h (n = 60 points) during a lights-out (dark) period. We observed a graded hierarchy of mean disorderliness of GH release that was quantifiable by ApEn measures, with maximal to minimal disorderliness in the following rank order: intact female, GnRH agonist-treated female, ovariectomized female, orchidectomized male, GnRH agonist-treated male, and intact male. These observations suggest a continuum of sex steroid actions on the regularity of GH secretion and, by inference, on the interplay among GH-releasing hormone, somatostatin, and GH/insulin-like growth factor I negative feedback.
阵发性生长激素（GH）释放的男性和女性特异性模式据推测是由性类固醇激素施加的，并且，尽管通常在视觉上很明显，但通过一种规律性统计量——近似熵（ApEn），在大鼠和人类中都能在数量上清晰地区分。GH分泌模式可能决定大鼠中GH刺激的生长以及特定的肝脏和肌肉基因表达。因此，识别其调节背后的机制很重要。在这里，我们通过手术或药理学[促性腺激素释放激素（GnRH）激动剂]干预，研究了青春期前性腺抑制（4周龄时）对雄性和雌性大鼠（10 - 11周龄）GH释放规律性（ApEn）的影响，在熄灯（黑暗）期间每隔10分钟采样一次，共10小时（n = 60个点）。我们观察到GH释放的平均无序度存在分级层次，可通过ApEn测量进行量化，无序度从最大到最小的顺序如下：完整雌性、GnRH激动剂处理的雌性、去卵巢雌性、去势雄性、GnRH激动剂处理的雄性和完整雄性。这些观察结果表明性类固醇对GH分泌规律性存在连续作用，并由此推断对生长激素释放激素、生长抑素和GH/胰岛素样生长因子I负反馈之间的相互作用也存在连续作用。
