A5017806032- Hypothalamic control of reproductive hormones
- Plant Reproductive Biology
- Ovarian function and disorders
- Reproductive Physiology in Livestock
- Neuroendocrine regulation and behavior
- Animal Nutrition and Physiology
- Sperm and Testicular Function
- Neuropeptides and Animal Physiology
- Reproductive Biology and Fertility
- Biochemical and Structural Characterization
- Veterinary Equine Medical Research
- Hormonal and reproductive studies
- Regulation of Appetite and Obesity
- Growth Hormone and Insulin-like Growth Factors
- Physiological and biochemical adaptations
- Effects of Environmental Stressors on Livestock
- Neurobiology and Insect Physiology Research
- Reproductive biology and impacts on aquatic species
- Plant Molecular Biology Research
- Receptor Mechanisms and Signaling
- Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities
- Estrogen and related hormone effects
- Aquaculture Nutrition and Growth
- Adipokines, Inflammation, and Metabolic Diseases
- Chinese history and philosophy
University of Otago
2019-2024
Physiologie de la Reproduction et des Comportements
2013-2023
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2022-2023
Université de Tours
2011-2023
Centre National de la Recherche Scientifique
2011-2023
Institut National de la Recherche Agronomique
2018
Centre Val de Loire
2018
Université Côte d'Azur
1986-1987
Laboratoire de Physiologie Cellulaire
1986-1987
Abstract The neuropeptide kisspeptin and its receptor, KiSS1R, govern the reproductive timeline of mammals by triggering puberty onset promoting ovulation stimulating gonadotrophin-releasing hormone (GnRH) secretion. To overcome drawback short half-life we designed analogs combining original modifications, triazole peptidomimetic albumin binding motif, to reduce proteolytic degradation slow down renal clearance, respectively. These showed improved in vitro potency dramatically enhanced...
Abstract The neuropeptide RFamide-related peptide 3 (RFRP-3) has been implicated in the control of gonadotropin secretion both birds and mammals. However, mammals, depending on species, sex photoperiod, inhibitory, excitatory, or no effect RFRP-3 plasma concentration LH reported. In ewe, treatment with either reduced had effect, an receptor antagonist (ie, RF9) resulted increased LH. To clarify these conflicting results present study, a set experiments was performed ewes. Multiple iv...
Abstract Excess levels of circulating androgens during prenatal or peripubertal development are an important cause polycystic ovary syndrome (PCOS), with the brain being a key target. Approximately half women diagnosed PCOS also experience metabolic syndrome; common features including obesity, insulin resistance and hyperinsulinemia. Although large amount clinical preclinical evidence has confirmed this relationship between reproductive PCOS, mechanisms by which dysregulation unknown....
New potent and selective KISS1R agonists were designed using a combination of rational chemical modifications the endogenous neuropeptide kisspeptin 10 (KP10). Improved resistance to degradation presumably reduced renal clearance obtained by introducing 1,4-disubstituted 1,2,3-triazole as proteolysis-resistant amide mimic serum albumin-binding motif, respectively. These triazololipopeptides are highly full >100 over closely related NPFF1R. When injected in ewes with quiescent reproductive...
Kisspeptin has emerged as the most potent gonadotropin-releasing hormone (GnRH) secretagogue and appears to represent penultimate step in central control of reproduction. In sheep, we showed that kisspeptin could be used manipulate gonadotropin secretion ovulation. Prompted by these results, decided investigate whether an ovulation-inducing agent another photoperiodic domestic mammal, horse. Equine kisspeptin-10 (eKp10) was administered intravenously bolus injections or short- long-term...
Abstract Polycystic ovarian syndrome (PCOS) is the leading cause of anovulatory infertility and a heterogenous condition associated with range reproductive metabolic impairments. While its etiology remains unclear, hyperandrogenism impaired steroid negative feedback have been identified as key factors underpinning development PCOS-like features both clinically in animal models. We tested hypothesis that androgen signaling kisspeptin-expressing neurons, which are drivers neuroendocrine axis,...
In temperate regions goat's reproduction is seasonal. To obtain year-round breeding, hormonal treatments are currently applied. These usually combine a progesterone analog with the pregnant mare serum gonadotropin (PMSG). However, their use has significant ethical and environmental drawbacks. Therefore, alternative methods to manage needed. The discovery that in mammals neuropeptide kisspeptin major positive regulator of hypothalamo-pituitary gonadal axis offered an attractive strategy...
Abstract 17α-Estradiol (17αE2), a less-feminising enantiomer of 17β-estradiol, has been shown to prolong lifespan and improve metabolic health in sex-specific manner male, but not female mice. Recent studies have demonstrated the pivotal role estrogen receptor α (ERα) mediating effects 17αE2 on health. However, specific tissues and/or neuronal signalling pathways that acts through remain be elucidated. ERα expression glutamatergic GABAergic neurons (principal excitatory inhibitory...
ABSTRACT An isolated in-vitro perifused interrenal gland preparation from the dogfish Scyliorhinus canicula was used to study production of quantitatively major corticosteroid 1α-hydroxycorticosterone (1α-OH-B), measured by radioimmunoassay. Basal secretory rates were 877·1 ± 145 ( s.e.m. ) fmol/mg per 15 min n =14) and remained viable for up 22 h, as reflected in a brisk response 10 μ m cyclic AMP (cAMP) after this time. Steroid responded dose-dependent manner porcine ACTH, with producing...
Somatostatin (SST) a neuropeptide involved in the central modulation of several physiological functions, is co-distributed same hypothalamic areas as kisspeptin (KP), most potent secretagogue gonadotropin-releasing hormone (GnRH) secretion known to date. As SST infused intracerebroventricularly (icv) evoked inhibition GnRH release, we explored neuroanatomical relationships between KP and populations male female rats. For that, intact males ovariectomised oestradiol-replaced females were...
Abstract Timing of puberty requires exquisite coordination genes, hormones, and brain circuitry. An increasing level body adiposity, signaled to the via fat-derived hormone leptin, is recognized as a major factor controlling onset. However, it clear that leptin not only metabolic cue regulating puberty, developmental regulation this process also involves tissues other than adipose, with muscle development potentially playing role in timing puberty. The proteolytic processing fibronectin type...
Agouti-related peptide (AgRP) neurons are thought to indirectly regulate the activity of hypothalamic gonadotrophin-releasing hormone which control fertility. AgRP also drive caloric intake and modulated by metabolically-relevant hormones, providing a link hypothalamic-pituitary-gonadal axis. In mice expressing Cre-dependant designer receptors (DREADDs) in neurons, we activated or silenced these vivo using synthetic ligand clozapine-N-oxide (CNO) observe effect neuron on timing puberty. To...
Timing of puberty has a great influence on animal productivity. For example, reproduction in sheep can be affected by seasonality, leading to fluctuations availability products. Therefore, optimization birth dates would improve reproductive success sheep. Since the discovery major role kisspeptin and Kiss1R, its cognate receptor, function, there are new opportunities for interventions. Repeated or continuous administration native able hasten induce ovulation during breeding non-breeding...
Abstract Context The neuropeptide RFRP-3 (RFamide-related peptide-3) is thought to play a role in the negative regulation of fertility. However, exogenous administration yields varying results depending on dose and route administration, sex subject, many other variables. Manipulation vivo neuronal activity using DREADDs (designer receptor exclusively activated by designer drugs) technology enables investigation cell type–specific activation manner that better reflects endogenous activity....
The modulation of the kisspeptin system holds promise as a treatment for human reproductive disorders and managing livestock breeding. design analogs has overcome some unfavorable properties endogenous ligands. However, applications requiring prolongation drug activity, such ovulation induction in ewe during non-breeding season, additional improvement is required. To this aim, we designed tested three formulations containing analog C6. Two were based on polymeric nanoparticles (NP1 NP2)...