Effect of Angiotensin II on Bovine Follicular Growth and mRNA Encoding Steroidogenic Enzymes, Gonadotrophin Receptors, and Tissue Development Genes.
Notice bibliographique
Résumé
Angiotensin II (AngII) has been shown to be involved in the regulatory mechanism of ovulation and oocyte nuclear and cytoplasmic maturation in cattle. In rats, AngII induces apoptosis in granulosa cells and atresia of antral follicles during follicular development. However, the angiotensin converting enzyme (ACE) mRNA expression increases at the end of follicular maturation, suggesting a possible modulatory role of AngII for ovulation in cows. In addition, the expression of AngII type 2 receptors (AGTR2) is higher in healthy than in atretic follicles and, in vitro, is stimulated by FSH in bovine granulosa cell culture. Based on this evidence, this study was carried out to establish the role of AngII during the follicular growth and the effect of AngII inhibition on steroid secretion and follicular cell gene expression profile. Cows were pre-synchronized to induce a new follicular wave and the largest follicle was injected with saralasin (AngII inhibitor; 10μM), AngII (10μM) or saline when it reached 7-8mm diameter. The intrafollicular injections were performed through a double-needle system and guided by a 7.5 MHz vaginal ultrasound probe. All follicles were monitored by ultrasonography for 96 hours after intrafollicular injection. Follicles injected with saline (control group) reached ovulatory size and ovulated after a challenge with the GnRH agonist gonadorelin, demonstrating that the intrafollicular injection did not affect follicular growth. Saralasin inhibited follicular growth in all treated cows (4/4), suggesting that AngII is essential for follicular growth in 7-8mm follicles. However, intrafollicular injection of AngII affected neither follicular growth nor the pattern of follicular dynamics, which were similar to control cows. These results imply that bovine ovarian follicles contain sufficient AngII for follicle development. In a second experiment, a single follicle of each cow was injected with saralasin or saline and cows were ovariectomized 24h later. The follicular fluid was aspirated to determine steroid concentrations, and granulosa and theca cells were recovered for gene expression measurement. Estradiol concentration in follicular fluid was determined by radioimmunoassay. Messenger RNA levels were analyzed by real-time RT-PCR and are expressed relative to cyclophilin. The inhibition of AngII action decreased abundance of mRNA encoding aromatase (CYP19), 3β-hydroxysteroid dehydrogenase (3β HSD), LH receptor, SerpinE2 and cyclinD2 in granulosa cells but not StAR, 17β HSD, FSH receptor, growth arrest and DNA damage inducible (GADD45b) or X-linked inhibitor of apoptosis protein (XIAP). In theca cells, the inhibition of AngII decreased the expression of AGTR2 but not the expression of steroidogenic enzymes genes. Taken together, these results show that AngII is essential for follicular growth, and plays important role in regulating genes involved in granulosa cell proliferation and differentiation, which are necessary for development of the dominant follicle. These data suggest that AngII signaling is involved in follicle growth and dominance in cattle. (poster)
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 | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| 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 ».