原発性aldosterone症における唾液中Na/K比に関する研究

The examination of the decrease in salivary sodium-potassium ratio has been considered significant in the diagnosis of hyperaldosteronism. The degree of the change in the ratio, however, was uncertain, and the present investigation was done to examine the diagnostic significance of the ratio. The sodiumpotassium ratio was obtained by flame photometry with the mixed saliva collected at 8 in the morning by the method of chewing a small piece of paraffin block. 1. The salivary sodium-potassium ratio was 0.65 and below in 7 cases of primary aldosteronism, whereas that in the normal control was in the range of 0.60-2.50. However, low ratios of 0 50 and below and 1.00 and below were also observed in two cases of malignant hypertension and 4 cases of renovascular hypertension, respectively. In 12 cases of essential hypertension, the ratio was 0.70 and over. An increase of the ratio to 0.70 and over was observed in 5 postoperative cases of primary aldo-steronism two weeks after the removal of the adrenocortical adenoma. Since low salivary sodium-potassium ratio was also observed in secondary aldosteronism such as mali-gnant hypertension and renovascular hypertension, the decrease in the ratio can not be served as the criterion in the differential diagnosis of aldosteronism, though the ratio of 1.00 and over may suggest that the case is not possibly of primary aldosteronism. 2. The renal potassium clearance when loaded by sodium thiosulfate (Cx(Na₂S₂O₃)) is high in primary aldosteronism, and the clearance is known to be mainly affected by the mineralocorticoid activity. A negative correlation was observed between salivary sodium-potassium ratio and simultaneously obtai-ned Cx (Na₂S₂O₃) in total 35 cases of primary aldosteronism, malignant hypertension, renovascular hype. rtension, essential hypertension, and Addison's disease, as well as in the normal control. The salivary sodium-potassium ratio may have some relation to the mineralocorticoid activity. 3. The salivary sodium-potassium ratio in the normal case was high in the morning, low in the da-ytime, and became high at night ; the urinary excretion of sodium and potassium was high in the dayti-me and low at night. Similar rhythm of the salivary sodium-potassium ratio was observed in primary aldosteronism and Addison's disease, while the diurnal rhythm of urinary excretion in primary aldosteronism was opposite to that of the control, and that in Addison's disease was often uncertain. The diurnal variation in the salivary sodium-potassium ratio seems to be affected by certain factor(s) different from the adrenocortical function, and the ratio may be controlled by some mechanism different from that controlling the urinary excretion of sodium and potassium.