Inhibition of ovarian steroidogenesis by cyclic GMP in a fly
in Journal of EndocrinologySearch for other papers by G Maniere in
Current site
Google Scholar
PubMed
Search for other papers by E Vanhems in
Current site
Google Scholar
PubMed
Search for other papers by F Gautron in
Current site
Google Scholar
PubMed
Search for other papers by JP Delbecque in
Current site
Google Scholar
PubMed
Previous investigations in the female blowfly Phormia regina have shown that 3-isobutyl-1-methylxanthine (IBMX), a broad spectrum inhibitor of phosphodiesterases (PDEs), fails to mimic the steroidogenic effects of cAMP on ovaries, although it efficiently increases the concentrations of this second messenger. In this study, experiments carried out to clear up this contradiction demonstrated that IBMX, besides its effect on cAMP, also increased cGMP concentrations in blowfly ovary and that these two cyclic nucleotides controlled ovarian steroidogenesis antagonistically. In particular, a selective inhibitor of cGMP-specific PDEs, unlike IBMX, had a very strong negative effect on ovarian steroidogenesis. Moreover, a cGMP analog was able to inhibit steroid biosynthesis in previtellogenic and vitellogenic ovaries, thus affecting basal and acute steroidogenesis respectively. Our observations also demonstrated that cGMP was always present in blowfly ovary, reaching its maximal levels at the end of vitellogenesis, in close correlation with the physiological decrease in ovarian steroidogenesis. Experiments using an inhibitor of protein kinase G clearly indicated that the effects of cGMP were mediated by this enzyme. On the contrary, these effects did not seem to involve cGMP-regulated PDEs or ion channels. Our results also indicated that ovarian cGMP concentrations were not controlled by brain factors, suggesting a probable involvement of paracrine/autocrine factors. Nitric oxide (NO) appeared to be a good candidate for such a control, because an NO donor was able to stimulate ovarian cGMP concentrations and to drastically decrease ovarian ecdysteroid biosynthesis in blowflies. These data thus demonstrate, for the first time in invertebrates, a potent role of cGMP in the negative control of ovarian steroidogenesis and suggest a possible co-regulation with NO.
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 | 151 | 50 | 5 |
| PDF Downloads | 92 | 33 | 2 |
Online ISSN: 1479-6805
Print ISSN: 0022-0795
Strengthening biomedical communities
to advance science and health
CONTACT US
Bioscientifica Ltd | Starling House | 1600 Bristol Parkway North | Bristol BS34 8YU | UK
Bioscientifica Ltd | Registered in England no 3190519