Archive for the ‘Follicle-Stimulating Hormone’ Category


The deleterious effects of FSH plus insulin on oocyte developmental competence observed in this study cannot directly reflect the physiological function of FSH during normal follicular development, since developmentally competent oocytes are produced in vivo even in the environment of high FSH concentrations in neonatal mice. Compared to the environment of the simple culture system used here, the milieu in which FSH functions in vivo is one of complex interactions with many other regulatory factors. Nevertheless, the deleterious effects of FSH plus insulin on oocyte development obtained here, using an experimental culture system involving the minimum follicular and culture components needed to support oocyte development, may help unravel the complex interactions between cells essential for normal oocyte development. For example, this study shows that conditions occurring during oocyte growth can have profound effects on oocyte competence to complete preimplantation development. buy yasmin online

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  • DISCUSSION(5)

    Both gap junctions and paracrine signaling mediate bidirectional communication between oocytes and companion granulosa cells. Paracrine factors secreted by oocytes suppress FSH-induced elevation of the steady-state level of LHR mRNA expression by granulosa cells. This probably explains, at least in part, the lack of expression of LHR and LHR mRNA by cumulus cells in preovulatory follicles. It was therefore unanticipated that oocytes grown in vitro were unable to suppress expression of LHR mRNA induced by FSH plus insulin in the cultured complexes. In experiments not shown, isolated oocytes grown in vitro were equivalent to oocytes grown in vivo in their ability to suppress FSH-induced elevation of LHR mRNA by mural granulosa cells in monolayer cultures. buy ventolin inhalers

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  • By what mechanism(s) might the combination of FSH and insulin affect the acquisition of oocyte developmental competence in this culture system? Evidence on whether oocytes express FSH receptors is conflicting, though most studies do not detect FSH binding or expression of FSH receptor mRNA by oocytes. In contrast, there is general acceptance that the oocyte’s companion granulosa cells express FSH receptors even in early stages of follicular development (see for review). Thus, if FSH affects oocyte development, this action would probably be indirect and mediated via granulosa cells. Neither FSH nor insulin alone had a harmful effect on developmental competence; it was the combination of these two agents that was deleterious to subsequent embryogenesis. buy cipro

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    The absence of a beneficial effect of FSH was puzzling and unexpected. Indeed, in experiments not shown, we tested several different regimens of FSH treatments, such as different concentrations at different times during the 10-day culture period, and combinations of treatment with FSH and estrogen. Among these conditions we never observed a beneficial effect of FSH on the acquisition of developmental competence. Nevertheless, further testing of potential competence-promoting effects of FSH in combination with other hormones and growth factors is continuing. flovent inhaler

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  • Treatment of hypogonadal mice with eCG in vivo increases the percentage of oocytes that undergo maturation, fertilization, and development in vitro to levels equivalent to those for oocytes from littermate control mice. It is well established that antral follicles undergo atretic degeneration in the absence of gonadotropic support. Thus, the only healthy antral follicles found in hypogonadal mice are small, since they only recently formed from secondary follicles. buy birth control online

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  • DISCUSSION(1)

    This study was undertaken to test the hypothesis that FSH treatment of cultured oocyte-granulosa cell complexes isolated from preantral follicles will improve the quality of oocytes by promoting growth and a higher frequency of embryonic developmental competence. The results did not support this hypothesis. FSH treatment of cultured complexes did not significantly affect oocyte growth, the percentage of oocytes acquiring competence to resume meio-sis, or the percentage of oocytes competent to undergo fertilization and preimplantation development. FSH or insulin alone did not significantly affect competence to complete preimplantation development. However, treatment of complexes with both FSH and insulin produced an unexpected, highly deleterious effect on competence to undergo development from the 2-cell stage to the blastocyst. ventolin 100 mcg

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  • To determine whether the state of differentiation of oocyte-associated granulosa cells could be correlated with deleterious effects on oocyte developmental competence, complexes were cultured in control medium (no FSH or insulin), FSH (5 ng/ml) without insulin, insulin (5 ^g/ml) without FSH, or 5 ng/ml FSH plus 0.05-5 ^g/ml insulin for 10 days, and the steady-state level of LHR mRNA expression was then measured. Comparing results on LHR mRNA expression, shown in Figure 6, with data on oocyte developmental competence, shown in Figure 4, did not indicate a correlation. For example, in the absence of insulin, there was high steady-state expression of LHR mRNA and high developmental competence when complexes were cultured with FSH alone; but this level of LHR mRNA expression was the same as in the FSH plus 5 ^g/ml insulin group wherein developmental competence was low. However, these data on granulosa cell expression of LHR mRNA were obtained after 10 days of culture, after much of the oocyte development in vitro had been completed. It seemed possible that, if inappropriate oocyte-associated granulosa cell differentiation or function is related to deficient oocyte-developmental competence, the stage of oocyte development sensitive to aberrant granulosa cell-oocyte communication might be earlier in the oocyte culture period. proventil inhaler

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  • RESULTS(5)

    Oocyte-cumulus cell complexes isolated from mouse preovulatory follicles do not undergo cumulus expansion or produce cAMP in response to highly purified LH. Therefore, the presence of functional LHRs was assessed by treating complexes after 10 days of culture with either highly purified LH (1 ^g/ml), FSH (1 ^g/ml), or control medium and 1) measuring cAMP production by RIA and 2) subjectively evaluating expansion (mucification) of the oocyte-associated granulosa cells. Neither cAMP production nor expansion was observed when oocyte-granulosa cell complexes were grown in medium without FSH for 10 days and then treated with either FSH or LH (Fig. 5). Cheap Diskus Advair

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