The Response to the Administration of an Isotonic Sodium Chloride-Lactate Solution in Patients With Essential Hypertension

Abstract

Many studies indicate that patients with essential hypertension have a greater natriuretic response to rapidly administered sodium chloride solutions than have normotensive individuals (1-7). However, in most instances other factors known to influence the rate of sodium excretion in the normal subject such as diet, posture, and time of day have not been rigidly controlled (8, 9). Dietary control is of particular importance in view of observations suggesting that patients with hypertension may habitually ingest more salt than do normotensive individuals (10-11). If this is indeed the case it might well be responsible for the enhanced response of the hypertensive patient to administered salt.The present report is concerned with a comparison of the response of hypertensive and normotensive individuals to the intravenous administration of an "isotonic-balanced" salt solution under rigidly controlled conditions and at three different levels of dietary salt ingestion. The results indicate that patients with essential hypertension excrete the infused sodium load more rapidly than do normotensive individuals at each level of salt consumption. METHODSFour niormal Caucasian males aged 29 to 36 and 6 Caucasian patients aged 24 to 63 with essential hypertension were studied. The patients were selected on the basis of their maintaining a resting diastolic blood pressure of at least 100 mm Hg while hospitalized and consuming a diet containing approximately 10 mEq of sodium daily. Five of the 6 subjects were observed in this manner for 13 to 47 days prior to study, while Patient 8 received the low salt diet for 8 days prior to study. No patient had congestive heart failure, although no. 5 had

Augmented Natriuretic Response to Acute Sodium Infusion after Blood Pressure Elevation with Metaraminol in Normotensive Subjects *

“…The augmented natriuresis observed is modest in comparison to the markedly enhanced natriuresis observed in patients with essential hypertension (2,5). Although this difference might be related to differences in the degree of hypertension or the duration of increased blood pressure, the present data do not permit further interpretation of this point.…”

“…This phenomenon has been repeatedly reported in patients with essential hypertension (1)(2)(3)(4)(5). Patients with hypertension caused by chronic glomerulonephritis (9, 10), Cushing's syndrome (4, 6, 7), pheochromocytoma (4), primary aldosteronism (8,11), and unilateral renal disease (10) have also been reported to have an exaggerated natriuretic response to acute salt loading, suggesting that elevated blood pressure could be a common denominator in this phenomenon.…”

“…That patients with essential hypertension have an exaggerated natriuretic response to the rapid intravenous administration of sodium is well established (1)(2)(3)(4)(5). Other hypertensive states have also been reported to exhibit an exaggerated natriuretic response to acute salt loading (4,(6)(7)(8)(9)(10)(11).…”

“…Other hypertensive states have also been reported to exhibit an exaggerated natriuretic response to acute salt loading (4,(6)(7)(8)(9)(10)(11). Although the mechanisms responsible for this phenomenon remain unknown (5), one of the possibilities is that the elevation of the blood pressure per se may cause the enhanced natriuresis (10).…”

Studies of the mechanism of contralateral polyuria after renal artery stenosis.

“…Hypertension is known to be associated with an exaggerated natriuresis during volume expansion (23,24), and in rats with Goldblatt or spontaneous hypertension transit time, and fractional water absorption through the loop of Henle is decreased (24). With volume expansion hypertensive animals had a greater increase in urine volume, sodium excretion, osmolar clearance, and TCHZO which was felt to be caused by increased pressure in the medullary circulation decreasing sodium reabsorption in the loop of Henle.…”