Increased abundance of aromatase and follicle stimulating hormone receptor mRNA and decreased insulin-like growth factor-2 receptor mRNA in small ovarian follicles of cattle selected for twin births1,2
| Autor: | Sherrill E. Echternkamp, D.R. Eborn, Pauline Y. Aad, Leon J. Spicer |
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| Rok vydání: | 2012 |
| Předmět: |
endocrine system
medicine.medical_specialty biology media_common.quotation_subject medicine.medical_treatment General Medicine Antral follicle Follicular fluid Insulin-like growth factor Endocrinology Theca Internal medicine Follicular phase Genetics biology.protein medicine Animal Science and Zoology Aromatase Follicle-stimulating hormone receptor Ovulation Food Science media_common |
| Zdroj: | Journal of Animal Science. 90:2193-2200 |
| ISSN: | 1525-3163 0021-8812 |
| DOI: | 10.2527/jas.2011-4735 |
| Popis: | Cattle genetically selected for twin ovulations and births (Twinner) exhibit increased ovarian follicular development, increased ovulation rate, and greater blood and follicular fluid IGF-1 concentrations compared with contemporary cattle not selected for twins (Control). Experimental objectives were to 1) assess relationships among aromatase (CYP19A1), IGF-1 (IGF1), IGF-2 receptor (IGF2R), and FSH receptor (FSHR) mRNA expression in small (≤5 mm) antral follicles and 2) determine their association with increased numbers of developing follicles in ovaries of Twinner females. Ovaries were collected from mature, cyclic (d 3 to 6) Twinner (n = 11), and Control (n = 12) cows at slaughter and pieces of cortical tissue were fixed and embedded in paraffin. Expression of mRNA was evaluated by in situ hybridization using (35)S-UTP-labeled antisense and sense probes for CYP19A1, FSHR, IGF1, and IGF2R mRNA. Silver grain density was quantified within the granulosa and theca cells of individual follicles (2 to 7 follicles/cow) by Bioquant image analysis. Follicles of Twinners tended to be smaller in diameter than Controls (1.9 ± 0.1 vs. 2.3 ± 0.1 mm; P = 0.08), but thickness of granulosa layer did not differ (P > 0.1) by genotype. Relative abundance of CYP19A1 (P 0.10). Detected increases in CYP19A1 and FSHR, but not IGF1, mRNA expression along with decreases in IGF2R mRNA expression in individual follicles of Twinners support the hypothesis that increased follicular development and steroidogenesis in Twinner females result from increased extra-ovarian IGF-1 production. Furthermore, a reduction in follicular IGF2R mRNA expression accompanied by a reduction in receptor numbers would increase availability of free IGF-2 and its stimulation of follicular development in Twinners. |
| Databáze: | OpenAIRE |
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