Hattori M, Wakabayashi K
Endocrinol Jpn. 1983 Aug;30(4):551-60. doi: 10.1507/endocrj1954.30.551.
Chicken LH components from the glycoprotein fraction of the anterior pituitary glands have been separated to isoelectric homogeneity by means of isoelectric focusing, and investigated for their biological activities in vitro. The activities of these components were measured with LH receptor binding, cyclic AMP accumulation and testosterone production in rat Leydig cells at equal doses expressed as immunoreactivity of IRC-2 (Gunma). All the components were active in the heterologous assay systems, although the relative potency expressed as the ratios of biological activity to immunoreactivity (B:I) differed significantly among the components. Component I, the amount of which is the largest (40-50%), with the most alkaline isoelectric point (pI) showed the highest B:I ratio, and the B:I ratio decreased with decreasing pI in the same way as in rat LH components (Wakabayashi, 1980; Hattori et al., 1983). Therefore, pituitary LH from photostimulated male quail, where the relative amount of component I was increased, was estimated to have higher B:I ratios than that from short-day (SD) treated male quail. Furthermore, the differences in activities among the components obtained by the three assays were in the following order: testosterone production greater than cyclic AMP accumulation greater than receptor binding, suggesting that the hormonal actions of components with higher B:I ratios (I, II and III) are efficiently amplified in the biological response to the final step. In the incubation of pituitary glands with hypothalamic extracts, component I in the pituitary glands from the long-day (LD) treated group was mostly decreased after the incubation, while all the components were decreased in parallel in the SD-treated group. The results suggest that the LH component releasable to GnRH changes in endocrine status though component I with the highest B:I ratio is relatively releasable in both SD- and LD-treated groups.
通过等电聚焦法，已将来自光刺激雄性鹌鹑垂体前叶糖蛋白部分的鸡促黄体生成素（LH）成分分离至等电均一性，并对其体外生物活性进行了研究。这些成分的活性通过LH受体结合、环磷酸腺苷（cAMP）积累以及以IRC - 2（群马）的免疫反应性表示的等剂量大鼠睾丸间质细胞中睾酮生成来测定。尽管以生物活性与免疫反应性之比（B:I）表示的相对效价在各成分之间存在显著差异，但所有成分在异源测定系统中均具有活性。成分I的含量最高（40 - 50%），等电点最碱性（pI），其B:I比值最高，并且B:I比值随着pI的降低而降低，与大鼠LH成分的情况相同（若林，1980；服部等人，1983）。因此，据估计，来自光刺激雄性鹌鹑的垂体LH，其成分I的相对含量增加，其B:I比值高于来自短日照（SD）处理雄性鹌鹑的垂体LH。此外，通过三种测定获得的各成分之间的活性差异顺序如下：睾酮生成大于cAMP积累大于受体结合，这表明具有较高B:I比值（I、II和III）的成分的激素作用在对最终步骤的生物反应中得到有效放大。在用下丘脑提取物孵育垂体时，长日照（LD）处理组垂体中的成分I在孵育后大多减少，而SD处理组中所有成分均平行减少。结果表明，可释放至促性腺激素释放激素（GnRH）的LH成分会随内分泌状态而变化，尽管具有最高B:I比值的成分I在SD和LD处理组中相对均可释放。
