[Pregnancy-induced hypertension and pre-eclampsia develop in spite of high circulating levels of cardionatrin].

Plasma cardionatrine was measured during pregnancy in 14 normotensive non pregnant women, 15 normotensive pregnant women, 35 pregnancy induced hypertension (PIH) and 10 preeclampsia (PE) and again 2 months after delivery in respectively 7, 15 and 7 cases together with plasma volume, PRA and plasma aldosterone. The plasma levels of cardionatrine are higher in pregnant normotensive women than in non pregnant normotensive women suggesting that pregnancy per se stimulates cardionatrine secretion. The higher levels of cardionatrine in PIH and specially in PE during pregnancy and the greater decrease of plasma cardionatrine after delivery in the hypertensive patients than in the normotensive controls exclude a deficiency of cardionatrine secretion in the pathogenesis of hypertension. These data rather suggest a compensatory role of cardionatrine in the prevention of blood pressure increase. Plasma volume was decreased in PIH (-17 p. 100) and in preeclampsia (-25 p. 100). The simultaneous high levels of cardionatrin may explain the inappropriate stimulation of the renin and aldosterone secretion in these hypovolemic hypertensive states.