Perfil hormonal y caracterización de los receptores hormonales en el ovario de Lagostomus maximus (Vizacacha) : un mamífero con poliovulación, supresión de la atresia folicular y ovulación durante la preñez
Lagostomus maximus is a rodent with a particular reproductive physiology. Females can ovulate up to 800 oocytes in each estrus cycle. During gestation, an ovulatory event has been described. This event would support to term the gestation through the formation of secondary corpora lutea. The objectiv...
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| Formato: | Tesis de maestría acceptedVersion |
| Lenguaje: | Español |
| Publicado: |
Facultad de Farmacia y Bioquímica
2017
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=afamaster&cl=CL1&d=HWA_2065 http://repositoriouba.sisbi.uba.ar/gsdl/collect/afamaster/index/assoc/HWA_2065.dir/2065.PDF |
| Aporte de: |
| Sumario: | Lagostomus maximus is a rodent with a particular reproductive physiology. Females can ovulate up to 800 oocytes in each estrus cycle. During gestation, an ovulatory event has been described. This event would support to term the gestation through the formation of secondary corpora lutea. The objectives of this study are to characterize the hormonal profile of L. maximus during ovulation, gestation and postpartum, as well as the dynamics of the hormonal receptors at the ovary. Therefore, the behavior of the hormones progesterone, 17?-estradiol, ?4-androstenedione, FSH and LH and their ovarian receptors at different reproductive moments were analyzed. L. maximus ovulation presents a similar mechanism to other mammals, where 17?-estradiol promote the LH peak. Moreover, two types of corpora lutea were observed: one product of ovulation and another that retains the oocyte. At mid-gestation L. maximus showed the highest serum progesterone levels. Subsequently, at days 91-120 pc the ovulation event during gestation was observed. This event was associated to a decrease in progesterone levels, followed by an increase in FSH, LH and 17?-estradiol. At this moment, it was observed an increased at the number of tertiary and antral follicles, with the consequent luteinization of the last. Serum progesterone levels were associated with a decrease in the functionality of the ovulation corpus luteum, which correlated with a decrease in the expression of RE?, RE?, RA and PGR. These data suggest: 1 - L. maximus ovulation, could be mediated by the positive feedback of 17?-estradiol on LH peak, previous follicular recruitment, 2- The ovulatory event during gestation is preceded by a follicular recruitment process, which is accompanied by an increase of FSH, LH, 17?-estradiol and a decrease in progesterone levels. This hormonal behavior is\nP á g i n a 14 | 156\nrelated to an activation of the hypothalamic-pituitary-gonadal axis during gestation with the purpose of generation of accessory corpora lutea, necessary to sustain the gestation to term. |
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