In contrast to PKA inhibitor, the MEK inhibitor blocked LH mediated Akt phosphorylation and androgen production in theca cells. Reportedly, the MAPK inhibitor also inhibits FSH mediated Akt phosphorylation in rat granulosa cells. While the precise mechanism for the activation of PI3K pathway by LH in theca cells is not known, it is possible that the LH induced phospho Akt up regulation may involve MAPK mediated down regula tion of phosphatase and tensin homologue. In this context, it has been shown that PI3K is required for estradiol stimulated hepatic cell growth and that the MAPK pathway reduces the level of PTEN, allowing estradiol induced phosphorylation of Akt. Whether this indeed is the case in the theca cells awaits further investigation.

As a mechanism explaining why phospho Akt content in theca cells was increased only after 12 h of incubation with {from this source| inhibitor|selleck chemicals|selleckchem|purchase LDC000067 LH, we are also interested in autocrine effects of insu lin like growth factor II and nerve growth factor on theca cells. Reportedly, theca cells express IGF II and NGF in cattle, and each of IGF II and NGF stimulate androgen production. Whether LH induces gene protein expression of these growth factors, and whether it modulates the LH mediated Akt phosphorylation in theca cells, are subjects that are currently under investigation in our laboratory. Conclusion Taking this evidence together, we conclude that LH stim ulates CYP17A1 mRNA expression and androgen produc tion in theca cells via activation of the PI3K Akt pathway. LH acts in theca cells by PKA independent mechanisms as well as PKA dependent mechanisms, each of which con trols androgen production.

article sourceBambuterol HCl Both the PI3K and the MAPK pathways coordinately regulate androgen production in bovine theca cells. Clarification of the LH mediated intra cellular signaling events is essential for better understand ing of not only ovarian physiology, but also of the pathophysiology of PCOS. Background In the United States, ovarian cancer represents 3% of all the new cancer cases in women, but accounts for 5% of all the cancer deaths. This discrepancy is due, in part, to the common resistance of ovarian cancer to cur rent chemotherapy regimens. The vast majority of ovar ian cancer patients with advanced disease are treated with surgery followed by adjuvant chemotherapy con sisting of a platinum agent in combination with a taxane. Unfortunately, while most patients initially respond to this combination chemotherapy, a majority of the patients will eventually relapse within 18 months, many with drug resistant disease. The optimal management of patients with recurrent tumors is unclear, especially for drug resistant disease, and various studies have suggested different second line che motherapy approaches, all with limited success.