Corticotrophin-releasing hormone and corticotrophin-releasing hormone binding protein in normal and pre-eclamptic human pregnancies.

OBJECTIVE: To measure the plasma levels of corticotrophin-releasing hormone and corticotrophin-releasing hormone binding protein in normal pregnancy and in pregnancies complicated by pre-eclampsia.
SETTING: John Radcliffe Hospital, Oxford and St Thomas's Hospital, London.
SUBJECTS: One hundred and twenty pregnant women sampled prospectively throughout gestation, of whom 91 experienced a normal pregnancy and eight developed pre-eclampsia; in a second study, 10 women with severe pre-eclampsia, presenting at a range of gestational ages, were sampled once and compared with appropriately matched normal pregnant women. MAIN OUTCOME MEASURE: Plasma levels of corticotrophin-releasing hormone determined by immunoradiometric assay. Plasma levels of corticotrophin-releasing hormone binding protein measured by direct radioimmunoassay.
RESULTS: In the prospective study, plasma samples from women with pre-eclampsia exhibited higher (390.2 versus 292.7 pmol/l at 36 weeks) levels of corticotrophin-releasing hormone and significantly lower (5.24 versus 8.14 nmol/l at 36 weeks, P < 0.002) levels of corticotrophin-releasing hormone binding protein than normal controls. In the second, single time point study a significant elevation in CRH (P < 0.002) and reduction in CRH-BP (P < 0.001) was found in pre-eclamptic pregnancies compared with controls.
CONCLUSIONS: In human pregnancies complicated by pre-eclampsia there is an elevated level of corticotrophin releasing hormone whilst there is less corticotrophin-releasing hormone binding protein; therefore there is a net increase in free potentially bioactive hormone which may play a role in the pathology of the disease.