This research involves a 7-10 year follow-up of identified populations of young adults to determine factors in adolescence associated with subsequent hypertension. We are following young mothers who, as adolescents, experienced hypertension during their first pregnancy and similar young mothers, normotensive during pregnancy. Recent follow-up studies at 3-6 years post partum indicate that women hypertensive during pregnancy and their children have higher blood pressure than controls; 14% of women hypertensive during pregnancy, but not control women, were found to have blood pressure greater than 140/90 on repeated measurements, and EKG studies showed evidence of increased left ventricular wall thickness. Group differences in renin-aldosterone responses to exercise were also found. We are following these women and their children to determine whether hypertension of pregnancy is associated with subsequent hypertension and the emergence of hypertensive cardiovascular disease in young mothers, and higher blood pressures in their children compared to controls. We are also conducting a follow-up of young adults who participated in a blood pressure screening project during high school in 1973. A five year follow-up indicated that individuals in this population maintain their relative rank-order for blood pressure over time, and blood pressure measurements during adolescence are predictive of subsequent blood pressure. Relatively high blood pressures are associated with an increased prevalence of abnormal echocardiograms and exercise EKG studies. We are re-evaluating these individuals after 7-10 years to determine if relative blood pressure rank is maintained; to determine whether relatively high blood pressure in adolescence predisposes to hypertension and hypertension of pregnancy; to study aggregation of cardiovascular disease risk factors in young adults; to identify early evidence of cardiovascular disease. Sympathetic nervous system activity, the renin-aldosterone axis, and steroid responses to grades ACTH infusions are being studied in "pre-hypertensive" young adults to identify mechanisms that may be involved in the pathogenesis of hypertension.