Addition of LY294002, but not wortmannin, significantly decreased LH induced CYP17A1 mRNA expression. Neither LH nor the PI3K inhibitors alter the mRNA levels of StAR in the theca cells. Experiment 4 Effect of PKA inhibitor and MEK inhibitor on LH induced Akt phosphorylation In fact, H89 did not affect LH mediated changes in Akt. On the other hand, Culture media were assayed for androstenedione by EIA. Values are means SEM for four experiments. Different let ters denote a significant difference of means. U0126 inhibited LH induced Akt phosphorylation in the theca cells. Although LH stimulated CYP17A1 mRNA expression and androstenedione production in the theca cells, the MAPK cascade inhibitor completely blocked these responses.
Discussion selleck In this study, we demonstrated that, 1 Akt is constitu tively expressed, but is gradually phosphorylated in cul tured bovine theca cells through exposure to LH, 2 LH stimulated androstenedione production in theca cells, although addition of the PI3K inhibitors attenuated LH induced androstenedione production, 3 LH increased CYP17A1 mRNA level in theca cells, whereas addition of LY294002 suppressed LH induced CYP17A1 expression in theca cells, 4 although H89 did not affect LH mediated changes in Akt, U0126 inhibited the LH induced Akt phosphorylation, CYP17A1 expression, and androgen production in theca cells. These results suggest that LH stimulates CYP17A1 mRNA expression and androgen production in theca cells via activation of the PI3K Akt pathway, and that the MAPK, not PKA, is involved in LH stimulation of the PI3K Akt cascade in bovine theca cells.
PI3K converts phosphatidylinositol 4,5 biphosphate to phosphatidylinositol 3,4,5 triphosphate, leading to acti vation of downstream kinases including Akt, which in turn phosphorylates Bad, forkhead in rhabdomyosar coma, Fas associated death domain selleck chemical CORM-3 like IL 1 converting enzyme like inhibitory protein, and X linked inhibitor of apoptosis protein. The body or anti total Akt antibody. Representative images and densitometric data of phos pho Akt contents, expressed as a ratio of phospho Akt to total Akt, are shown. Values show the mean SEM for three experiments. Each experiment was reproduced at least three times. Different letters denote significant differ ences of means. PI3K Akt activation drives cell through many biological functions, including gene expression, cell cycle, survival, glucidic metabolism, endocytosis and vesicular traffick ing, cell transformation, and oncogenesis. In ovary, FSH and several growth factors are known to activate the PI3K Akt pathway and prevent apoptosis in granulosa cells and cultured follicles.