家蚕蜕皮与变态的内分泌调控

Endocrine control of molting and metamorphosis in Bombyx mori

家蚕的蜕皮与变态是由前胸腺分泌的脱皮素（ｍｏｌｔｉｎｇ ｈｏｒｍｏｎｅ或 ｅｃｄｙｓｔｅｒｏｉｄ简称 ＭＨ）及由咽侧体分泌的保幼激素（ｊｕｖｅｎｉｌｅ ｈｏｒｍｏｎｅ）控制的，而促有前胸腺激素（ｐｒｏｔｈｏｒａｃｉｃｏｔｒｏｐｉｃ ｈｏｒｍｏｎｅ，以下简称ＰＴＴＨ）的功能为刺激前胸腺分泌蜕皮素。笔者近１０年来从家蚕内分泌体系的一系列研究中发现，蜕皮素浓度的变化可以通过控制咽侧体的保幼激素的生物合成来影响幼虫发育，而ＰＴＴＨ的信息传递可通过调控前胸腺的功能，进而影响血淋巴中蜕皮素浓度。

Insect molting and metamorphosis are controlled by ecdysteroids, produced by the prothoracic glands, and juvenile hormone (JH), produced by the corpora allata (CA). The production of ecdysteroid is stimulated by the prothoracicotropic hormone (PTTH). In recent several years, using silkworm, Bombyx mori as a model system, hormonal control of insect molting and metamorphosis has been studied. It is found that changes in hasal hemolymph ecdysteroid levels in this insect can modulate JH biosynthetic activity of (CA), with very low ecdysteroid levels during the early last larval instar leding to the inactivation of CA. It is also found that the PTTH signal transduction undergoes a development-specific change during the fourth and last larval instars. A review of the current knowledge on hormonal control of insect molting and metamorphosis has also been given.