Relationship between serum prolactin concentration, vascular angiotensin sensitivity and arterial blood pressure during third trimester pregnancy.

Prolactin may play an important role in the pathogenesis of pregnancy-induced hypertension (PIH) and preeclampsia. In 105 normotensive nulliparous women at 28 to 32 weeks of gestation, the relationship between serum prolactin concentration (PRL) and blood pressure behaviour was examined under standardized conditions. Neither postural change from left lateral to supine recumbency nor the infusion of low doses of angiotensin-II-amide had an effect on PRL levels. Similar mean PRL levels were found in pregnant women with a low angiotensin pressor dose (ADP less than 10 ng x kg-1 x min-1) or "angiotensin sensitivity", a positive supine pressor response (delta pd greater than or equal to 20 mmHg) or an increased serum uric acid concentration (greater than 3.6 mg/dl), which are criteria for an increased risk of developing hypertensive complications. However, in the group of subjects with angiotensin sensitivity, a significant correlation was found (a) between PRL levels and the APD and (b) between PRL levels and diastolic blood pressure increase after 5 min of supine recumbency. These results may reflect diminished dopaminergic activity in the central nervous system, which could influence both blood pressure and prolactin secretion.