Tag Archives: gene regulation

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(6)


Previous studies from our laboratory have shown that FSH increases follicular transforming growth factor a secretion and that this theca-derived growth factor induces follicular growth in vitro. In this context, recent studies using a coculture of bovine ovarian granulosa and theca cells have shown that the theca cells are essential in protecting granulosa cells from undergoing apoptosis, a process that is follicular stage-specific. These results suggest that theca cells may secrete one or more survival factors necessary for maintenance of granulosa cell viability, although the identity of this factor is yet to be defined. It is also possible that the regulation of follicular growth by FSH is mediated by the action of TNFa. buy Endep online

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(5)

Our present findings indicate that although FSH is capable of increasing follicular cell number (as indicated by increased Alamar Blue reduction and DNA content) and growth in a follicle culture system, it fails to stimulate proliferation when added to granulosa cell primary cultures. The reason for this apparent discrepancy is not clear, but the granulosa cells used in the present studies may have been exposed to LH (in the eCG preparation) in vivo before isolation and culture, resulting in premature luteinization of the cells and, consequently, exit from the cell cycle. cialis super active canada

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(4)


Specifically, XIAP possesses two different caspase-inhibitory activities, which can be attributed to distinct domains within XIAP. The BIR3 of XIAP is a specific inhibitor of cas-pase-9, whereas BIR2 plus the linker region of BIR1 and BIR2 is specific for caspase-3 and caspase-7. The IAPs suppress Fas ligand- and TNFa-induced apoptosis by directly inhibiting caspase-3 and caspase-7 activation and activity, but they are ineffective in the activation of caspase-1, caspase-6, or caspase-10. generic female Viagra

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(3)

Follicles infected with XIAP sense and cultured in the presence of low FSH concentration (5 ng/ml) showed a marked increase in follicular development (as evidenced by increases in DNA content and follicular volume) compared to the FSH-stimulated but LacZ-infected follicles. The XIAP sense was ineffective in the absence of gonadotropin. These findings suggest that whereas XIAP is necessary for the suppression of apoptosis, it alone is insufficient to promote follicular growth. These findings do not exclude the possible involvement of other IAPs in the gonadotrophic regulation of follicular development and atresia. generic Kamagra online

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(2)


Transgenic and knockout animals have been used extensively to assess the role of the gene (or genes) of interest in physiological processes. However, these approaches are often plagued with systemic complications because of overall ill health of the animals, which often affects normal development. The IAPs are ubiquitous and found in high abundance in proliferating mammalian cells. Despite a newly established NAIP knockout mice model, no XIAP knockout animal model was available until recently to enable assessment of the role of XIAP in the gonadotrophic regulation of follicular development and atresia. Whereas no apparent differences were observed between the ability of cells from the XIAP-deficient and wild-type mice to undergo caspase-dependent or -independent apoptosis, the cellular levels of other IAPs (e.g., cIAP-1 and cIAP-2) were unexpectedly higher, suggesting the existence of a possible compensatory mechanism that leads to the up-regulation of other IAP family members when XIAP expression is lost. generic levitra canada

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(1)

The FSH is an important survival factor for preantral and antral follicular development in vivo. Whereas administration of gonadotropin induces ovarian follicular development in immature animals, gonadotropin withdrawal by anti-eCG antibody treatment resulted not only in cessation of follicular growth but also in atresia. In the present study, we have successfully established a rat follicle culture system and have demonstrated that FSH stimulates rat ovarian follicular growth and induces antral formation in a 6-day culture period. Our findings are consistent with the results of recent studies involving cultures of bovine, baboon, mouse, rat, and hamster ovarian follicles. This culture system may prove to be useful for assessment of the endocrine control of follicular development and atresia. Levitra professional Canadian pharmacy

Role and Gonadotrophic Regulation of X-Linked: RESULTS(4)

RESULTS(4)Influence of FSH on Granulosa Cell XIAP Expression and Apoptosis In Vitro

To test if the FSH-induced follicular growth and increase in cell number in vitro is caused by a direct action of gonadotropin on granulosa cells to stimulate proliferation and/ or suppress apoptosis, granulosa cells were cultured for 48 h in the absence or presence of FSH (100 ng/ml). Analysis of variance indicates that although FSH significantly decreased granulosa cell apoptosis compared to control (P < 0.01), total granulosa cell number was markedly lower in the presence of gonadotropin (P < 0.02, two-way ANOVA) (Table 1), irrespective of up- or down-regulation of XIAP (P < 0.05, Tukey test). Propecia from Canadian pharmacies

Role and Gonadotrophic Regulation of X-Linked: RESULTS(3)

On the other hand, follicles injected with XIAP sense and subsequently cultured in the low concentration of FSH (5 ng/ml) showed high XIAP immunointensity and less-intense TUNEL signal compared to adenoviral LacZ-in-jected follicles (Fig. 5B). Although a range in the intensity in both XIAP and TUNEL signals was observed within each experimental group, the differences between groups (LacZ vs. XIAP sense vs. XIAP antisense) were obvious. Similarly, XIAP sense infection significantly increased XIAP protein content (P < 0.01) (Fig. 7) and suppressed apoptotic DNA fragmentation (P < 0.05) (Fig. 7). The increase in XIAP expression following adenoviral XIAP sense infection was not associated with any significant changes in DNA content and follicular volume (P > 0.05) (Fig. 8) in the absence of FSH. generic Viagra Canada

Role and Gonadotrophic Regulation of X-Linked: RESULTS(2)

RESULTS(2)FSH Increases XIAP Expression in Cultured Ovarian Follicles

To determine if XIAP expression is regulated by the gonadotropin during follicular development and atresia in vitro, changes in XIAP content and apoptosis in sections of cultured follicles were examined by IHC and TUNEL, respectively (Fig. 5A). Whereas follicles cultured in the absence of FSH for 2 and 4 days showed low XIAP immu-noreactivity and detectable apoptotic signal, addition of FSH (100 ng/ml) to the culture medium markedly increased XIAP expression (Fig. 5A) and decreased the apoptotic signal (Fig. 5A). In addition, gonadotropin also significantly increased follicular XIAP content (P < 0.05) (Fig. 6) and suppressed apoptotic DNA fragmentation (P < 0.05) (Fig. 6). Viagra professional Canadian pharmacy

Role and Gonadotrophic Regulation of X-Linked: RESULTS(1)

FSH Stimulates Ovarian Follicular Growth In Vitro

Follicles cultured for up to 6 days in the absence of FSH exhibited minimal growth (Day 6 vs. Day 0), as evidenced by an absence of change in follicular size (follicular volume: 3.4 ± 0.55 nl vs. 2.6 ± 0.22 nl, n = 43), cell number equivalence (2.8 ± 0.35 vs. 1.5 ± 0.15, n = 46, as determined by Alamar Blue reduction), and DNA content (2.5 ± 0.39 ng/follicle vs. 1.2 ± 0.18 ng/follicle, n = 40) (Fig. 2A). Addition of FSH (100 ng/ml) to the culture medium significantly increased these parameters (follicular volume: 33.6 ± 3.26 nl, n = 43; cell number equivalence: 11.2 ± 2.35, n = 46; DNA content: 21.5 ± 3.39 ng/follicle, n = 40; P < 0.002 vs. control) (Fig. 2A). The increases in cell number equivalence, follicular volume, and daily growth rate were maximal on Day 3 of culture (Fig. 2, A and B). Viagra super active Canadian pharmacy

Pages: 1 2 3 Next