Blazsek I, Balázs A, Novák V J, Malá J
Cell Tissue Res. 1975;158(2):269-80. doi: 10.1007/BF00219965.
The prothoracic gland (PGL) of Galleria mellonella is a Y-shaped, paired organ, consisting of 45-50 polyploid giant cells. The PGL cells are supplied by neurosecretory axons; release of neurosecretory granules (1000-1300 A in diameter) directly on the surface of PGL cells was frequently observed. Based on ultrastructure, the last two larval instars can be divided into three phases: 1) restitutive phase immediately after moulting; 2) gradual activation in mid-intermoult as indicated by the logarithmic cell growth, decrease of nucleo-cytoplasmic ratio, increase in the number of cell organelles participating in protein synthesis, and the structural changes of these organelles; 3) "release' period preceding moulting, characterized mainly by the extreme dilatation of peripheral invaginations. From the prepupal stage onward cellular activity is asynchronous. Part of the cells already show the signs of involution, while others histolyse only after the activation phase subsequent to moulting. PGL in G. mellonella is one of the larval tissues. In the course of activation its ultrastructure changes as a function of juvenile hormone (JH) cocentration, in the absence of which it histolyses. Accordingly, it has seemed to us to be a suitable model for the cytological study of JH activity.
大蜡螟的前胸腺（PGL）是一个呈Y形的成对器官，由45 - 50个多倍体巨细胞组成。PGL细胞由神经分泌轴突提供营养；经常观察到神经分泌颗粒（直径为1000 - 1300埃）直接释放到PGL细胞表面。根据超微结构，最后两个幼虫龄期可分为三个阶段：1）蜕皮后立即进入恢复阶段；2）在龄期中段逐渐激活，表现为细胞对数生长、核质比降低、参与蛋白质合成的细胞器数量增加以及这些细胞器的结构变化；3）蜕皮前的“释放”期，主要特征是外周内陷极度扩张。从预蛹期开始，细胞活动就不同步。一部分细胞已经显示出退化的迹象，而其他细胞只有在蜕皮后的激活阶段之后才会发生组织溶解。大蜡螟中的PGL是幼虫组织之一。在激活过程中，其超微结构会随着保幼激素（JH）浓度的变化而改变，在没有JH的情况下它会发生组织溶解。因此，在我们看来，它是研究JH活性的细胞学合适模型。
