The biotransformation of tritiated 3-dehydroecdysone by crayfish,Procambarus clarkii

The injection of 3-dehydroecdysone (3dhE, 5 /g), the major ecdysteroid secreted by the Y-organ of crayfishProcambarus clarkii, resulted in apolysis within about 5 days. The hormonal response at the molecular level was investigated by injection of the radio-labeled compound; within 3 h of injection of [³H]3dhE, most radio-isotope was found in the extracted epidermal tissues and identified as ecdysone, 20-hydroxyecdysone (20E), and their 3-hydroxy epimers. The biotransformation was undoubtedly performed in the peripheral area of the Y-organ. Cleavage of the polar conjugates, using an enzyme fromHelix pomatia, gave all of the above ecdysteroids including 3dhE. It was also found that the biosynthetic site of 3dhE was different from that of ecdysone at the subcellular level of the Y-organ.     

In vitro secretion of ecdysteroids by Y-organs of the crayfish,Procambarus clarkii

It was demonstrated that excised Y-organs of the crayfish,Procambarus clarkii, synthesize in vitro 3-dehydroecdysone (3-DHE) as the major product, together with small amounts of ecdysone. Both were identified by immunological and spectroscopic methods. The increase of ecdysteroidogenesis in the Y-organs was accompanied by an increase of the major free ecdysteroid, 20-hydroxyecdysone, in the hemolymph. This suggests a physiological role of 3-DHE, the details of which are still to be elucidated.     

锯缘青蟹Y器结构与卵巢发育的研究

锯缘青蟹的Y器位于前鳃腔、眼柄的后外侧，其显著特点是细胞紧密排列，细胞核几乎占据了整个腺细胞，异染色质极其丰富，细胞突起多，细胞器少。线粒体具管状嵴，细胞内常见不同大小的空泡，卵巢成熟之前，Y器具有巨大脂肪球；腺细胞胞质少，空泡数量较多，以小泡为主，线粒体基质电子密度高。卵巢将成熟时，腺细胞胞质体积有所增大，多泡小体、髓样小体和大空泡增多，线粒体基质电子密度低，内嵴膨大或消失，表明腺细胞分泌作用逐渐减弱。锯缘青蟹Y器超微结构的变化，为其蜕皮类固醇参与卵巢发育的生理作用提供了形态学依据。