Rensing L, Fischer M
Cell Differ. 1975 Oct;4(4):209-17. doi: 10.1016/0045-6039(75)90027-5.
Salivary glands of late third instar larvae of Drosophila melanogaster were isolated at a developmental stage when the release of ecdysone had already taken place. They were then incubated in a chemically defined medium. An ecdysone-dependent developmental puff sequence was measured in vitro and influenced by adding various substances or by changing iso-osmotically the sodium or potassium content of the medium. Trinactin, valinomycin N-ethylmaleimide and KCN blocked the puff sequence, i.e. the regression of the early and the induction of the late ecdysone-dependent puffs probably by increasing the Na+ influx and depleting the ATP content of the cell. A medium that contained Na+ as the only monovalent cation decreased the size of the late ecdysone-dependent puffs and increased the size of other puffs, such as 50 CD. Addition of tetrodotoxin to the normal medium had the opposite effect, i.e., it increased 63 E and inhibited 50 CD. Na+ free medium, inhibition of K+ flux by tetraethylammonium chloride, and application of ouabain did not considerably influence the size of the puffs measured. It is concluded from these results that Na+ in particular has an inhibitory effect on the induction of late ecdysone-dependent puffs. Na+ (and perhaps also K+) may act by modulating the effect of proteins that are involved in gene control mechanisms.
黑腹果蝇三龄幼虫后期的唾液腺是在蜕皮激素已经释放的发育阶段分离出来的。然后将它们置于化学成分明确的培养基中培养。在体外测量了蜕皮激素依赖性的发育胀泡序列，并通过添加各种物质或等渗改变培养基中的钠或钾含量来对其进行影响。三活菌素、缬氨霉素、N - 乙基马来酰胺和氰化钾阻断了胀泡序列，即早期胀泡的消退和后期蜕皮激素依赖性胀泡的诱导可能是通过增加钠离子内流和消耗细胞内的ATP含量来实现的。一种仅以钠离子作为单价阳离子的培养基会减小后期蜕皮激素依赖性胀泡的大小，并增大其他胀泡（如50 CD）的大小。向正常培养基中添加河豚毒素则产生相反的效果，即增大63 E并抑制50 CD。无钠培养基、用氯化四乙铵抑制钾离子通量以及应用哇巴因对所测量的胀泡大小没有显著影响。从这些结果可以得出结论，特别是钠离子对后期蜕皮激素依赖性胀泡的诱导具有抑制作用。钠离子（也许还有钾离子）可能通过调节参与基因控制机制的蛋白质的作用来发挥作用。
