Immediately preovulatory levels of messenger ribonucleic acid for inhibin alpha-subunit are diminished in granulosa cells from successful in-vitro fertilization-embryo transfer

Inhibin, a gonadal glycoprotem which suppresses pituitary gonadotrophin secretion, preferentially follicle stimulating hormone, has been extensively characterized. It consists of two covalently bound subunits, the α- and β-subunits, encoded by separate genes. In this study, the expression of messenger ribonucleic acid (mRNA) for the inhibin α-subunit was studied by Northern blot analysis in granulosa cells of women undergoing in-vitro fertilization/embryo transfer (IVF/ET). Three patient groups were studied: women who failed to become pregnant (n=11), women who became pregnant but experienced early spontaneous abortion (n=3) and women who conceived normal ongoing pregnancies (n=4). Granulosa cells were obtained at the time of follicle aspiration. Levels of alpha-subunit mRNA were 40% lower in patients establishing normal pregnancies than in those who failed to become pregnant or who spontaneously aborted. Thus, a relative diminution of immediately preovulatory levels of mRNA for inhibin α-subunit Is a marker of success in clinical LVFIET cycles. This marker of IVF/ET success can be related to previously established markers of success (increased follicular fluid oestradiol and decreased follicular fluid cyclic adenosine monophosphate) by known physiological mechanisms.