DOES PLASMA-IMMUNOREACTIVE OUABAIN ORIGINATE FROM THE ADRENAL-GLAND

It was reported recently that the endogenous digitalis-like factor oua bain may mainly originate from the adrenal gland. To ascertain the pat hophysiological significance of endogenous ouabain and to examine if i t originates in the adrenal gland, we determined plasma immunoreactive ouabain levels in patients with various cardiovascular and endocrine diseases. Plasma immunoreactive ouabain levels were also determined in the adrenal venous blood by adrenal venous sampling. Plasma immunorea ctive ouabain levels were significantly increased in patients with ess ential hypertension, primary aldosteronism, Cushing's syndrome, pheoch romocytoma, acromegaly, and chronic renal failure. Plasma immunoreacti ve ouabain levels were decreased in patients with primary aldosteronis m after unilateral adrenalectomy, acromegaly after pituitary adenomect omy, and chronic renal failure after hemodialysis. Plasma immunoreacti ve ouabain levels in patients after bilateral adrenalectomy were simil ar to those in healthy subjects. There was no significant step-up of i mmunoreactive ouabain levels in the adrenal vein from the peripheral v ein in three patients, whereas one patient with hypertension and right adrenal tumor but without any known adrenal hormone excess showed hig her plasma immunoreactive ouabain levels in the right adrenal vein tha n those in the peripheral vein. These results suggest an important pat hophysiological significance of endogenous ouabain in various cardiova scular and endocrine diseases. It is unlikely that the adrenal gland i s a major source of plasma ouabain, although a possible excess product ion of ouabain by the adrenal tumor remains to be elucidated.