Mary H. Majercik

Immunoreactive endothelin-1 concentrations in follicular fluid of women with and without endometriosis undergoing in vitro fertilization-embryo transfer

OBJECTIVE To determine the concentrations of immunoreactive (IR) endothelin-1 in human follicular fluid (FF) and whether IR-endothelin-1 levels are different in women with endometriosis-associated infertility. DESIGN Follicular fluid and plasma samples, obtained from women with and without endometriosis undergoing IVF-ET, were collected at the time of oocyte aspiration and analyzed for IR-endothelin-1 levels. SETTING Infertility clinic in an academic research environment. RESULTS Overall, 90% of FF samples and 60% of plasma samples contained IR-endothelin-1 detectable above the threshold of assay sensitivity. Immunoreactive endothelin-1 levels (mean +/- SEM) in FF samples from women with and without endometriosis-associated infertility were 74 +/- 12 and 37 +/- 6 pg/mL, respectively. There was no difference in IR-endothelin-1 levels in FF samples between controlled ovarian hyperstimulation cycles with or without leuprolide acetate. No significant differences were detected in plasma IR-endothelin-1 levels in women with endometriosis-associated infertility when compared with those without. CONCLUSIONS These results demonstrate the presence of IR-endothelin-1 in human FF obtained at the time of oocyte aspiration for IVF-ET and higher levels of IR-endothelin-1 in FF of women with endometriosis-associated infertility.

Epidermal growth factor modulates intracellular arachidonic acid levels in MA-10 cultured Leydig tumor cells

Epidermal growth factor (EGF) acts on various cell types, including the mouse Leydig tumor cell line MA-10, where it has been shown to stimulate steroidogenesis, apparently in a cAMP-independent manner. In the process of examining other possible signaling pathways for EGF in these cells, we found rapid changes in the intracellular concentration of arachidonic acid (AA) following addition of EGF. For example, a significant increase in AA was detected 1 min after incubating the cells with EGF, with the maximal effect observed at an EGF concentration of 10 ng/ml. In addition, exogenous AA increased steroidogenesis, and the steroidogenesis enhanced by AA and EGF was reduced by lipoxygenase inhibitors, suggesting a possible role of an AA metabolite(s) in promoting steroidogenesis. Consistent with this hypothesis is our observation that several exogenous lipoxygenase metabolites were capable of enhancing progesterone production. The EGF-stimulated steroidogenesis was also inhibited by two phospholipase A2 inhibitors, again confirming a probable role of AA or a metabolite in this process. Therefore, AA appears to be an important intracellular mediator responsible, at least in part, for some of the acute metabolic effects mediated by EGF in MA-10 cells.

Cytoskeletal Regulation of hCG-Induced Receptor Clustering in Transformed Leydig Cells

The gonadotropins, human choriogonadotropin (hCG) and lutropin (LH), act through the same G protein-coupled receptor to stimulate steroidogenesis in target cells, an action that is generally associate