Notice bibliographique
Résumé
In galliformes, prolactin (PRL) is thought to have both pro- and anti-gonadal effects on steroidogenesis by ovarian follicles dependent on its concentration. However, the role of the major isoform (glycosylated PRL, G-PRL) is unknown. Therefore, a comparison between non-glycosylated (NG-) and G-PRL on steroidogenesis in chicken different size class follicles was carried out. Contrary to the observations in mammals where G-PRL generally shows lower bioactivity than NG-PRL, both isoforms affected both basal and gonadotrophin-stimulated steroidogenesis over a broad concentration range. In granulosa cells of either preovulatory F3-F1 or prehierarchical 6-8 mm follicles, lower levels of NG-PRL stimulated basal estradiol (E2) and progesterone (P4) secretion but at higher levels this effect was reduced. However, G-PRL inhibited basal E2 and P4 secretion in a dose-dependent manner in prehierarchical granulosa cells in contrast to an inducible effect in preovulatory granulosa cells. In accordance with the data for steroids, levels of StAR, CYP11A1, CYP19A1 and 3β-HSD transcripts were up- or down-regulated by both isoforms. Furthermore, G-PRL was less potent than NG-PRL in suppressing FSH- or LH-induced E2 and P4 secretion in preovulatory granulosa cells, whereas G-PRL reduced but NG-PRL enhanced FSH-induced P4 secretion in prehierarchical granulosa cells. In the population of prehierarchical < 6 mm follicles, NG-PRL had a greater effect on suppressing FSH-induced E2 secretion than G-PRL, whereas G-PRL was more effective than NG-PRL in suppressing FSH-induced P4 production. In contrast, with the exception of the synergistic actions of LH and G-PRL on P4 production in the 4-6 mm follicles, both isoforms reduced LH-stimulated E2 and P4 production in all < 6 mm follicles. Thus, glycosylation of PRL can differentially modify its actions on basal and gonadotropin-stimulated steroidogenesis depending on the concentration, the type of gonadotropin (FSH or LH) and the stage of follicle development. Consistent with the effects of PRL on steroidogenesis, the PRL receptor (PRLR) was widely distributed in the follicular hierarchy, with the highest expression in the < 2 mm follicles and a progressive decline as the follicles matured. FSH had the greatest stimulatory effect on expression of PRLR in prehierarchical granulosa cells but this effect declined with follicle maturation, whereas LH showed no effects in all follicular classes examined. NG- and G-PRL were observed to have differential effects on basal and FSH-mediated PRLR expression according to the concentration and the stage of follicle development. As a newly identified ligand for the PRLR in non-mammalian vertebrates including chickens, PRL-like protein (PRL-L) had a similar expression pattern to PRLR during follicle development, with maximal expression in the < 2 mm follicles. Furthermore, PRL-L was more abundant in prehierarchical than preovulatory granulosa cells. FSH increased while LH did not affect expression of PRL-L in prehierarchical granulosa cells. Basal and FSH-induced PRL-L expression were differentially regulated by either isoform of PRL depending on the concentration. Therefore, it is suggested that the differential actions of PRL isoforms on follicular cell steroidogenesis are mediated through modulating the expression of PRLR and PRL-L. By using activators and/or inhibitors, we further demonstrated that in prehierarchical granulosa cells, multiple signaling pathways including PKA, PKC, PI3K-Akt-mTOR and AMPK were not only directly involved in but they could also converge to modulate ERK2 activity to regulate FSH-induced PRLR and PRL-L expression.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,004 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».