The pathophysiological role of digitalis-like substance in essential hypertension.
In order to investigate the role of digitalis-like substance in patients with essential hypertension, levels of plasma digitalis-like substance were measured in nine normotensive, 12 normal-renin and seven low-renin essential hypertensive subjects. The level of plasma digitalis-like substance was determined by using two different methods, the digoxin radio-immunoassay established by our laboratory and Na+,K+-ATPase inhibitory activity (modified Hamlyn's method). There was a significant positive correlation between plasma immunoreactive digitalis-like substance and Na+,K+-ATPase inhibitory activity in plasma samples. Both values were significantly higher in hypertensives than in normotensives. Moreover, Na+,K+-ATPase inhibitory activity was significantly higher in low-renin hypertensives than in normal-renin hypertensives or normotensives. These findings suggest (1) digoxin radio-immunoassay may be able to determine the level of plasma digitalis-like substance; (2) digitalis-like substance is increased in essential hypertensives, especially in low-renin hypertensives; (3) the level of digitalis-like substance might be related to plasma renin activity, and mediated by a change in plasma volume; and (4) the activity of the digitalis-like substance may contribute to the pathophysiology of essential hypertension.
Saitoh
S
S
Second Department of Internal Medicine, Sapporo Medical College, Japan.
Shimamoto
K
K
Nakagawa
M
M
Yamaguchi
Y
Y
Matsuda
K
K
Kuroda
S
S
Ura
N
N
Iimura
O
O
D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000378:metabolism*; D002298:Cardenolides; D004077:Digoxin; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D008875:Middle Aged; D011863:Radioimmunoassay; D012083:Renin / Q000097:blood; D012503:Saponins; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D004077:Digoxin; D012083:Renin; D000254:Sodium-Potassium-Exchanging ATPase