Inhibin-A and pro-alpha C are elevated in preeclamptic pregnancy and correlate with human chorionic gonadotropin

Serum concentrations of the heterodimeric glycoprotein inhibin-A (alpha-beta A) and its alpha-subunit increase during pregnancy. The placenta is the predominant source of inhibin during pregnancy, and a paracrine role in the trophoblast has been suggested. Elevated serum concentrations of inhibin alpha-subunit as well as the glycoprotein human chorionic gonadotropin (hCG) have been described in preeclamptic pregnancy. The objectives of this investigation were to compare serum concentrations of inhibin-A and inhibin pro-alpha C in preeclamptic and normotensive pregnancy, and to examine the relationship of hCG and inhibin-A in those pregnancies.

A case-control design using 32 patients with preeclampsia with a single fetus at 32-40 weeks of gestation and 34 gestation age-matched normotensive control subjects was used for this investigation. Solid-phase enzyme-linked immunosorbent assays were used to measure inhibin-A and inhibin pro-alpha C in sera. An immunoradiometric assay was used to measure intact hCG.

Inhibin-A and inhibin pro-alpha C concentrations were significantly elevated in the sera of women with preeclampsia compared with those concentrations in normotensive control subjects (P < 0.05). A relationship of inhibin-A or pro-alpha C with severity of preeclampsia was not observed. There was a significant positive correlation of serum hCG with both inhibin-A and pro-alpha C (P < 0.05).

Levels of inhibin-A and the subunit pro-alpha C are increased in pregnancies complicated by preeclampsia. These findings are potentially the effect of a paracrine role of inhibin-A in the development and proliferation of the trophoblast.