Variation de l'activité endocrine des cerveaux en fonction de l'espèce, du sexe et du cycle vital chez quelques Néréidiens (annélides polychètes)

Porchet, M.

doi:10.1016/0016-6480(72)90212-2

Cited by 16 publications

(11 citation statements)

References 12 publications

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“…As the animal ages, it has been suggested that there is a staged decline in the circulating hormone titre (Durchon & Porchet 1971;Porchet 1972). The animal's ability to regenerate lost segments is greatly reduced (Golding 1967), and this is coupled with a decrease in the growth rate of the animal.…”

Section: Endocrine Control Of Reproductionmentioning

confidence: 99%

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Lawrence

Soame

2009

Phil. Trans. R. Soc. B

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Nereidae are vital to the functioning of estuarine ecosystems and are major components in the diets of over-wintering birds and commercial fish. They use environmental cues to synchronize reproduction. Photoperiod is the proximate cue, initiating vitellogenesis in a temperature-compensated process. The prevailing paradigm in Nereidae is of a single ‘juvenile’ hormone controlling growth and reproduction. However, a new multi-hormone model is presented here that integrates the environmental and endocrine control of reproduction. This is supported by evidence from in vitro bioassays. The juvenile hormone is shown to be heat stable and cross reactive between species. In addition, a second neuro-hormone, identified here as a gonadotrophic hormone, is shown to be present in mature females and is found to promote oocyte growth. Furthermore, dopamine and melatonin appear to switch off the juvenile hormone while serotonin and oxytocin promote oocyte growth. Global warming is likely to uncouple the phase relationship between temperature and photoperiod, with significant consequences for Nereidae that use photoperiod to cue reproduction during the winter in northern latitudes. Genotypic adaptation of the photoperiodic response may be possible, but significant impacts on fecundity, spawning success and recruitment are likely in response to short-term extreme events. Endocrine-disrupting chemicals may also impact on putative steroid hormone pathways in Nereidae with similar consequences. These impacts may have significant implications for the functional role of Nereidae and highlight the importance of comparative endocrinology studies in these and other invertebrates.

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Section: Endocrine Control Of Reproductionmentioning

confidence: 99%

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Lawrence

Soame

2009

Phil. Trans. R. Soc. B

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“…This has prompted enquiry as to the possible effects of transplanting brains into decerebrate hosts (Golding 1983). From these results, it appears that, contrary to what was previously assumed (Durchon and Porchet 1971;Porchet 1972), there is little or no change in cerebral endocrine activity throughout most of the process of gametogenesis in N. diversicolor, at least as long as there is continued recruitment of oocytes. Thus, the fact that brain secretion reaches a high plateau that lasts for all but the final 5 months of the life cycle accounts for the maintenance of a heterogeneous population of immature oocytes.…”

Section: The Brain Hormonementioning

confidence: 59%

“…In the 1970s, organ-culture techniques were used to test brain endocrine activity in order to relate the levels of brain hormone(s) to particular stages of gametogenesis (Durchon and Porchet 1971;Porchet 1972). It appeared that major reductions in secretory activity were spaced throughout gametogenesis in both N. diversicolor and P. cultrifera.…”

Section: The Brain Hormonementioning

confidence: 99%

Endocrine and environmental control of reproduction in Polychaeta

Andries¹

2001

Can. J. Zool.

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In Polychaeta, as in many invertebrates, reproduction is controlled by both environmental and endocrine factors. Although the effects of environmental factors on reproductive behaviour are briefly discussed, this review focuses on the endocrinology of reproduction. As Nereidae are the most intensively studied polychaetes, their epigamic monotelic strategy is discussed first in this review. Although a large number of physiological observations have been made, biochemical data have been greatly lacking until recent years, except, however, for the recent isolation of several pheromones. These substances, such as uric acid and L-cysteine gluthathione disulfide, occur widely and must be present at high concentrations in order to exert their physiological effects. Results obtained from iteroparous species are also considered. The stolonization strategy of Syllidae, the control of vitellogenesis in Nephtyidae, Phyllodocidae, Polynoidae, and Cirratulidae, and the regulation of gamete maturation in Arenicolidae and Pectinariidae are discussed. As with Nereidae, our knowledge of endocrine control is mainly based on experimental data, since only spermmaturation factor in the genus Arenicola has been identified. Therefore, despite numerous interesting experimental studies in which functional roles for polychaete reproductive hormones have been described, their nature, their primary targets, and their mechanism of action are unfortunately still largely unknown.Résumé : Chez les polychètes, comme chez de nombreux invertébrés, la reproduction est sous le contrôle de facteurs de l'environnement et de facteurs endocriniens. L'objet essentiel de cette synthèse est le contrôle endocrinien de la reproduction; des données plus fragmentaires ont trait aux effets des facteurs environnementaux. Puisque les Nereidae sont les polychètes les mieux connus, l'étude de leur stratégie monotélique épigame est envisagée dans un premier point. Toutefois, malgré de nombreuses observations physiologiques, peu de données biochimiques sont disponibles, si l'on excepte l'isolement récent de plusieurs phéromones. Celles-ci, comme l'acide urique et le disulfure de L-cystéine glutathion, sont des substances ubiquistes qui, de ce fait, doivent être présentes en concentrations élevées afin de pouvoir exercer une action physiologique. Les résultats obtenus chez les espèces itéropares font l'objet d'un second point. La stratégie de stolonisation des Syllidae, le contrôle de la vitellogenèse des Nephtyidae, des Phyllodocidae, des Polynoidae et des Cirratulidae, ainsi que le contrôle de la maturation des gamètes des Arenicolidae et des Pectinariidae sont examinés. Comme dans le cas des Nereidae, notre compréhension du contrôle endocrinien repose essentiellement sur des données expérimentales. Seul est identifié le facteur de maturation des spermatozoïdes d'Arenicola. Ainsi, malgré les nombreuses études expérimentales réalisées chez les polychètes et les multiples actions hormonales décrites dans les processus de reproduction, la nature des hormones, leurs cibl...

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“…Comparison with those of Durchon and Porchet (1971), and Porchet (1972), who have quantified the activity of brain homogenates using an in vitro bioassay procedure, reveals significant discrepancies. Mature brains show a virtual absence of endocrine activity as assessed by those authors, whereas a significant, albeit diminished, level of activity is apparently retained according to our results.…”

Section: Discussionmentioning

confidence: 85%

Patterns of cerebral endocrine activity innereis diversicolor (annelida: Polychaeta)

AL‐Sharook

Golding

1979

Marine Behaviour and Physiology

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The brain of Nereis has a diversity of endocrine actions on processes associated with growth and sexual reproduction. Regeneration-promoting, maturation-inhibiting, and gametotrophic activities have been studied by transplating brains from animals at various stages of the life cycle into decerebrate, immature hosts. Endocrine activity declines greatly during gametogenesis. In animals approaching sexual maturity, maturation-inhibiting activity is extinguished, whereas a low but significant level of regeneration-promoting activity, and gametotrophic activity, is retained. The close correlation of these activities supports their postulated mediation by a single hormone, although the processes subject to endocrine control show different thresholds for hormone action.

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Variation de l'activité endocrine des cerveaux en fonction de l'espèce, du sexe et du cycle vital chez quelques Néréidiens (annélides polychètes)

Cited by 16 publications

References 12 publications

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

The endocrine control of reproduction in Nereidae: a new multi-hormonal model with implications for their functional role in a changing environment

Endocrine and environmental control of reproduction in Polychaeta

Patterns of cerebral endocrine activity innereis diversicolor (annelida: Polychaeta)

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