de Kleijn D P, Janssen K P, Waddy S L, Hegeman R, Lai W Y, Martens G J, Van Herp F
Department of Animal Physiology, Faculty of Science, University of Nijmegen, The Netherlands.
J Endocrinol. 1998 Feb;156(2):291-8. doi: 10.1677/joe.0.1560291.
Crustacean reproduction is regulated by a complex chain of hormonal interactions in which the crustacean hyperglycaemic hormones A and B (CHH-A and CHH-B) and the gonad-inhibiting hormone (GIH) play a primary role. These neurohormones are produced in the same neuroendocrine cells of the X-organ sinus gland complex, situated in the eyestalks of the American lobster, Homarus americanus. In order to obtain more information on the synthesis, storage, release and function of these three neuropeptides during the reproductive cycle, we studied the levels of their mRNAs in the X-organ, their peptide storage in the sinus gland and their concentration in the haemolymph at different stages of the female reproductive cycle. A high CHH-A mRNA level was found only in the previtellogenic stage, while elevated mRNA levels were determined for CHH-B in the mature as well as the previtellogenic stage. High CHH storage levels in the sinus gland were found during previtellogenesis. The total amount of CHH (CHH-A plus -B) in the haemolymph was significantly higher during maturation. A low level of GIH mRNA in the X-organ and a low amount of the GIH I isoform in the sinus gland were found only in the immature stage. In contrast, GIH haemolymph levels were high during the immature and previtellogenic stages. We conclude that CHH-A and -B are involved in triggering the onset of vitellogenesis and that CHH-B in particular is responsible for stimulating oocyte maturation before spawning, while GIH prevents the start of vitellogenesis in the ovary. Moreover, our results show that the balance between the haemolymph levels of the CHHs and GIH may tune the synchronization of reproduction and molting during the biannual reproductive cycle of the American lobster.
甲壳类动物的繁殖受一系列复杂的激素相互作用调节，其中甲壳类动物高血糖激素A和B（CHH - A和CHH - B）以及性腺抑制激素（GIH）起主要作用。这些神经激素由位于美洲龙虾（美洲螯龙虾）眼柄中的X器官 - 窦腺复合体的相同神经内分泌细胞产生。为了获取关于这三种神经肽在生殖周期中的合成、储存、释放和功能的更多信息，我们研究了它们在X器官中的mRNA水平、在窦腺中的肽储存以及在雌性生殖周期不同阶段血淋巴中的浓度。仅在卵黄发生前期发现高CHH - A mRNA水平，而在成熟阶段以及卵黄发生前期均检测到CHH - B的mRNA水平升高。在卵黄发生前期，窦腺中发现高CHH储存水平。在成熟期间，血淋巴中CHH（CHH - A加 - B）的总量显著更高。仅在未成熟阶段发现X器官中GIH mRNA水平低以及窦腺中GIH I同工型含量低。相反，在未成熟和卵黄发生前期阶段，GIH血淋巴水平较高。我们得出结论，CHH - A和 - B参与触发卵黄发生的开始，特别是CHH - B负责在产卵前刺激卵母细胞成熟，而GIH阻止卵巢中卵黄发生的开始。此外，我们的结果表明，CHHs和GIH血淋巴水平之间的平衡可能调节美洲龙虾半年生殖周期中繁殖和蜕皮的同步性。
