Smith W A, Gilbert L I, Bollenbacher W E
Mol Cell Endocrinol. 1984 Oct;37(3):285-94. doi: 10.1016/0303-7207(84)90098-4.
The involvement of cAMP in the steroidogenic action of the cerebral neuropeptide, prothoracicotropic hormone (PTTH), was examined in the tobacco hornworm, Manduca sexta. PTTH stimulates ecdysone synthesis by paired organs in the thorax, the prothoracic glands. The steroidogenic effect of PTTH on prothoracic glands of day 3 fifth instar larvae and day 0 pupae is mimicked in vitro by agents that act by increasing the intracellular levels of cAMP (1-methyl-3-isobutylxanthine, cAMP analogs and forskolin). In addition, partially purified big PTTH (Mr 28500 daltons) stimulates the formation of cAMP in both stages of glands in a rapid, dose-dependent manner. However, a significant accumulation of cAMP in response to PTTH occurs only in larval prothoracic glands. In pupal glands, effects of the neuropeptide on cAMP synthesis are seen only in the presence of a phosphodiesterase inhibitor. The results indicate that cAMP is involved as a second messenger in PTTH action, but that the developmental status of the prothoracic glands influences the degree to which cAMP accumulates in response to the neurohormone.
在烟草天蛾（Manduca sexta）中，研究了环磷酸腺苷（cAMP）在脑源神经肽促前胸腺激素（PTTH）的类固醇生成作用中的参与情况。PTTH刺激位于胸部的成对器官前胸腺合成蜕皮激素。在体外，通过增加细胞内cAMP水平起作用的试剂（1-甲基-3-异丁基黄嘌呤、cAMP类似物和福斯高林）可模拟PTTH对3日龄五龄幼虫和0日龄蛹的前胸腺的类固醇生成作用。此外，部分纯化的大PTTH（分子量28500道尔顿）以快速、剂量依赖性方式刺激两个阶段腺体中cAMP的形成。然而，仅在幼虫前胸腺中，对PTTH的刺激会出现cAMP的显著积累。在蛹腺中，该神经肽对cAMP合成的影响仅在存在磷酸二酯酶抑制剂的情况下才可见。结果表明，cAMP作为第二信使参与PTTH的作用，但前胸腺的发育状态会影响其对神经激素刺激时cAMP积累的程度。
