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.
Journal of Endocrinology is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
Sept 2018 onwards | Past Year | Past 30 Days | |
---|---|---|---|
Full Text Views | 258 | 129 | 52 |
PDF Downloads | 185 | 73 | 3 |