Genetic aspects of plasma aldosterone binding globulins in families of patients with essential hypertension, including isolation of novel thermostable homologues from plasma and urine

Two new thermostable aldosterone binding globulins were partially characterised in plasma (ABG-TS) and urine (ABD-TSu) of normal humans. Analysis comprised ultrafiltration, dialysis, incubation at 37°C preceding or following DEAE cellulose chromatography (pH gradient), and Sephadex G75 chromatography. Both compounds had a molecular weight and isoelectric point similar to that of the already described plasma thermolabile ABG. In studies on the effect of potassium canrenoate, with physiologic range, on aldosterone ABG binding in vivo in 4 out of 7 and in vitro in 9 hypertensives, a decrease, probably due to a specific competitive displacement of aldosterone, was observed. The transmission of high ABG capacity, as reflecting high plasma ABG concentration, was studied in three generations of 40 French Canadian families from the Montreal area. Samples were taken from 304 relatives (aged 2 1 2 −84 ) of two known essential hypertensive (EH) parents, and also from 290 controls (aged 4–65). Relatives with values similar to controls were designated “normal” in contrast to relatives carrying the high ABG binding trait designated “affected”. In “affected” relatives, total mid-afternoon to early evening plasma aldosterone was similar to that of normal relatives or controls but the free fraction was less (P