Lewis C E, Morris J F, Fink G
J Endocrinol. 1985 Aug;106(2):211-8. doi: 10.1677/joe.0.1060211.
We have investigated the possibility that microfilaments are involved in the priming effect of LH-releasing hormone (LHRH) by ultrastructural morphometry of hemipituitary glands from adult female mice. Glands incubated for 2 consecutive hours with 8.5 nmol LHRH/l responded with a marked increase in the amount of LH released into the medium during the second hour compared with the first hour of incubation. This priming effect of LHRH on LH secretion was accompanied by a significant margination of secretory granules and a drop in the total granule content of the gonadotrophs. Although the number of microfilaments remained the same, there was an increase in their length and a change in orientation so that the angle between the microfilaments and the plasmalemma was significantly reduced after both the first and second hour of exposure of LHRH. The addition of 14.3 mumol cytochalasin B/1 to the incubation medium significantly increased the amount of LH released in the first hour of incubation when compared with the amount of LH released by LHRH alone, but completely abolished the priming effect of LHRH. Cytochalasin B also prevented the LHRH-induced increase in the length and the change in orientation of the microfilaments. These results indicate that LHRH priming involves an increase in length of microfilaments and a change in their orientation relative to the plasmalemma.
我们通过对成年雌性小鼠半垂体进行超微结构形态测定，研究了微丝是否参与促性腺激素释放激素（LHRH）的启动效应。与孵育的第一个小时相比，用8.5 nmol LHRH / l连续孵育2小时的腺体，在第二个小时向培养基中释放的LH量显著增加。LHRH对LH分泌的这种启动效应伴随着分泌颗粒的明显边缘化和促性腺激素细胞总颗粒含量的下降。尽管微丝的数量保持不变，但其长度增加且方向发生变化，因此在LHRH暴露的第一个小时和第二个小时后，微丝与质膜之间的角度均显著减小。与单独使用LHRH释放的LH量相比，向孵育培养基中添加14.3 μmol细胞松弛素B / l可显著增加孵育第一个小时释放的LH量，但完全消除了LHRH的启动效应。细胞松弛素B还阻止了LHRH诱导的微丝长度增加及其方向变化。这些结果表明，LHRH启动涉及微丝长度的增加及其相对于质膜方向的变化。
