Functional significance of the signal transduction pathways Akt and Erk in ovarian follicles: <it>in vitro</it> and <it>in vivo</it> studies in cattle and sheep

<p>Abstract</p> <p>Background</p> <p>The intracellular signalling mechanisms that regulate ovarian follicle development are unclear; however, we have recently shown differences in the Akt and Erk signalling pathways in dominant compared to subordinate follicles. The aim...

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Main Authors: Ryan Kate E (Author), Glister Claire (Author), Lonergan Pat (Author), Martin Finian (Author), Knight Phil G (Author), Evans Alexander CO (Author)
Format: Book
Published: BMC, 2008-10-01T00:00:00Z.
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Summary:<p>Abstract</p> <p>Background</p> <p>The intracellular signalling mechanisms that regulate ovarian follicle development are unclear; however, we have recently shown differences in the Akt and Erk signalling pathways in dominant compared to subordinate follicles. The aim of this study was to investigate the effects of inhibiting Akt and Erk phosphorylation on IGF- and gonadotropin- stimulated granulosa and theca cell function <it>in vitro</it>, and on follicle development <it>in vivo</it>.</p> <p>Methods</p> <p>Bovine granulosa and theca cells were cultured for six days and stimulated with FSH and/or IGF, or LH in combination with PD98059 (Erk inhibitor) and/or LY294002 (Akt inhibitor) and their effect on cell number and hormone secretion (estradiol, activin-A, inhibin-A, follistatin, progesterone and androstenedione) determined. In addition, ovarian follicles were treated <it>in vivo</it> with PD98059 and/or LY294002 in ewes on Day 3 of the cycle and follicles were recovered 48 hours later.</p> <p>Results</p> <p>We have shown that gonadotropin- and IGF-stimulated hormone production by granulosa and theca cells is reduced by treatment with PD98059 and LY294002 <it>in vitro</it>. Furthermore, treatment with PD98059 and LY294002 reduced follicle growth and oestradiol production <it>in vivo</it>.</p> <p>Conclusion</p> <p>These results demonstrate an important functional role for the Akt and Erk signalling pathways in follicle function, growth and development.</p>
Item Description:10.1186/1757-2215-1-2
1757-2215