Anastomosis of the ovarian vein to the hepatic portal vein in sheep induces ovarian hyperstimulation associated with increased LH pulsatility, but only in the absence of the contralateral ovary
| Autor: | J. C. Poirier, Danielle Monniaux, D. Garcès, P. G. Knight, J. C. Mariana, M. R. Blanc, C. Pisselet, A. Collet, Joël Fontaine |
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| Přispěvatelé: | ProdInra, Migration, Physiologie de la reproduction et des comportements [Nouzilly] (PRC), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2000 |
| Předmět: |
LH
Follistatin [SDV]Life Sciences [q-bio] Endocrinology Diabetes and Metabolism 0302 clinical medicine Endocrinology Ovarian Follicle FSH Follicular phase ComputingMilieux_MISCELLANEOUS Progesterone 2. Zero hunger 0303 health sciences 030219 obstetrics & reproductive medicine Estradiol Anastomosis Surgical Activins [SDV] Life Sciences [q-bio] medicine.anatomical_structure Liver Female Folliculogenesis Luteinizing hormone Ovarian vein endocrine system medicine.medical_specialty Ovariectomy Ovary [INFO] Computer Science [cs] Luteal phase Biology Models Biological 03 medical and health sciences Aromatase Mesenteric Veins Internal medicine medicine Animals [INFO]Computer Science [cs] Inhibins 030304 developmental biology Glycoproteins Estrous cycle Sheep Hypertrophy Luteinizing Hormone Follicular fluid Follicular Fluid |
| Zdroj: | Journal of Endocrinology Journal of Endocrinology, BioScientifica, 2000, 165 (2), pp.411-423 |
| ISSN: | 0022-0795 1479-6805 |
| Popis: | In this study, two experiments were performed, the first of which examined the ovarian response in ewes that were subject to unilateral ovariectomy (ULO) at different intervals (0-14 days) after surgical anastomosis (AN) of the ovarian vein to the mesenteric vein (n=7 ewes), or sham operation (SO; n=4 ewes). Hypertrophy and development of multiple follicular and luteal structures on AN ovaries were observed after ULO, while SO ovaries remained of normal size and appearance after ULO. The second experiment involving 11 ewes (five AN; six SO) aimed to clarify the mechanism by which AN following ULO-induced ovarian hypertrophy and increased follicle development. The results confirmed that there were more large (>5 mm) follicles on AN compared with SO ovaries; however, their rate of atresia was similar. Oestradiol and progesterone concentrations in follicular fluid of class 1 follicles (5-9 mm) were higher in AN ovaries than those in control follicles of the same size collected in the late follicular phase of an induced oestrous cycle. In AN ewes, intrafollicular progesterone concentrations increased while follicular aromatase activity and intrafollicular oestradiol, inhibin A, follistatin and activin A concentrations all decreased as follicle size increased. Oestradiol and progesterone concentrations were substantially higher in ovarian venous blood than in hepatic venous blood, both in AN and SO ewes, whereas inhibin A levels were not significantly modified by passage through the liver in either group. Mean plasma LH concentration, and LH pulse frequency and amplitude increased markedly after AN but were not affected by SO. Plasma FSH showed only a small transient increase after AN, presumably due to the maintenance of inhibin feedback. Injection of prostaglandin F(2)(alpha) 4 days later did not further modify LH or FSH secretion in either group. Full ovariectomy (FO) 9-14 days after AN or SO increased LH secretion markedly in SO ewes but to a lesser degree in AN ewes; FO induced a large and rapid increase in FSH levels in both groups. In conclusion, AN of the ovary to the liver via the mesenteric vein provides a useful model for studying the feedback between the ovary and the hypothalamo-pituitary system and the mechanisms controlling follicle development. The present results indicate that the pattern of LH secretion is an important factor controlling the terminal phase of follicle development in the ewe. |
| Databáze: | OpenAIRE |
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