HIGH-LEVELS OF CORTICOTROPIN-RELEASING FACTOR (CRF) ARE INVERSELY CORRELATED WITH LOW-LEVELS OF MATERNAL CRF-BINDING PROTEIN IN PREGNANT-WOMEN WITH PREGNANCY-INDUCED HYPERTENSION

Corticotropin-releasing factor-binding protein (CRF-BP) is suggested t o play a role in modulating the activity of the hypothalamus-pituitary -adrenal axis during pregnancy, counteracting the actions of circulati ng or locally acting CRF. The aim of the present study was to evaluate whether maternal levels of CRF-BP and CRF are modified in pregnant wo men with a high risk of developing pregnancy-induced hypertension (n = 21). A group of nine patients developed the disease between 25-35 wee ks gestation, and sequential blood samples were taken every 5 weeks th roughout the pregnancy. As a control group, healthy pregnant women wer e studied (n = 9) using the same protocol; a group of women with pregn ancy-induced hypertension (n = 5) was studied starting from the time o f diagnosis. In a subgroup of patients (n = 10), CRF-BP and CRF levels were studied after 5 weeks of antihypertensive treatment. Levels of C RF-BP mere determined using a specific RIA, whereas CRF was evaluated by a two-site immunoradiometric assay. In patients at risk, circulatin g levels of CRF-BP followed the same pattern as that in healthy contro ls, showing a significant decrease at term (36-40 weeks; P < 0.05). A significant and progressive increase in plasma CRF levels was observed in both groups of pregnant women; the highest values were found at te rm (P < 0.01). In the nine patients who developed pregnancy-induced hy pertension, maternal levels of CRF-BP at the onset of signs and sympto ms were lower than control values, and CRF levels were significantly h igher at the onset of the disease (P < 0.01). Similarly, in these hype rtensive patients studied at the time of hospitalization, CRF-BP level s were lower whereas those of CRF were higher than levels in healthy p atients (P < 0.01). No effect of antihypertensive therapy on either CR F-BP or CRF levels was observed. The present study shows an inverse co rrelation between reduced plasma CRF-BP levels and increased CRF level s in the maternal circulation of patients with pregnancy-induced hyper tension, and indicates that these hormonal changes do not occur before the onset of disease, suggesting that the measurement of these polype ptides in maternal plasma does not predict the development of hyperten sion.