Reduced Na+, K+-ATPase Activity in Patients with Pseudohypoaldosteronism

Abstract

ABSTRACT. Pseudohypoaldosteronism is a hereditary wasting syndrome varies widely with age and is particularly salt-wasting syndrome usually seen in infancy with weight severe in infancy. Spontaneous improvement in sodium conserloss, dehydration, and failure to thrive. The patho-vation occurs as the individuals become older. Aldosterone dephysiologic origin of pseudohypoaldosteronism is un-ficiency in the face of overproduction of zona glomerulosa 18-known. The defect could be related to the unresponsiveness hydroxycorticosterone (10) was found, an abnormality for which of target organs to mineralocorticoids resulting in hypo-the term type 2 corticosterone methyl-oxidase defect was coined natremia, hyperkalemia, and markedly elevated plasma (1 1). Treatment with mineralocorticoids and high-sodium diet aldosterone and renin levels. Red blood cell Na+,K+-ATP reduces the secretion of the aldosterone precursor, restores elecase activity was measured in a pair of twins with pseudo-trolyte balance, and normalizes the growth rate (3). hypoaldosteronism, in an unrelated child with hypoaldosLittle information has been added in regard to the pathoteronism, and in an age-matched group of 50 healthy physiologic expression of PHA since its original description by infants and young children. The enzyme was assayed by a Cheek and Peny (12) in 1958. It is believed that patients with method that couples A T P hydrolysis with NADH oxida-PHA represent a blunted target organ responsiveness to aldostertion. Plasma renin and aldosterone levels were measured one either because of a reduced number in mineralocorticoid by RIA. Red blood cell Na+,K+-ATPase activity in the (type 1) receptors (13) or a low receptor affinity to aldosterone twins with pseudohypoaldosteronism was very low a t the (14). A defect in sodium reabsorption along the proximal tubule time of diagnosis (3 wk). In both twins a time-related and the loop of Henle has also been suggested (15). Low Na+,K+-gradual increase in enzyme activity was observed during ATPase activity in both proximal and distal tubular segments in the 1st mo of life, reaching control values between 6 and 8 a child with PHA has been demonstrated previously (16). No mo of age. This increase was associated with both a reduc-further data substantiating these findings have been published. tion in salt requirement and clinical improvement. Plasma In the present study we investigated RBC Na+,K+-ATPase activrenin activity and aldosterone levels were very high a t the ity in a pair of twins with PHA and in an infant with HA to time of diagnosis. Plasma renin activity reverted gradually clarify the pathophysiologic expression of PHA. to normal values, whereas aldosterone levels remained high throughout the follow-up period. The child with hypoaldosteronism had normal Na+,K+-ATPase activity a t diag- The twins were born at 35 wk of gestation weighing 2.3 and 2.2 RBC, red blood cell kg, respectively. At the age of 3 wk, they were hospitalized HA, hypoaldosteronism because of vomiting, lethargy, and loss of app...

Transient type 1 pseudo-hypoaldosteronism: report on an eight-patient series and literature review

“…The renal effects of most hormones or cytokines, produced by combined action of UT obstruction and endotoxin include vasoconstriction, reduced glomerular filtration rate and increased natriuresis [10,56,57]. The reduction in tubular sodium transport is due, at least in part, to decreased Na/K adenosine triphosphatase (ATPase) activity [58]. It is also speculated that bacterial toxins can transiently damage aldosterone receptors, although permanent damage to at least some of these receptors could occur, as indicated by prolonged elevation of aldosterone and plasma renin activity [13,15,18,44].…”

Sodium potassium adenosine triphosphatase activity in preterm and term infants and its possible role in sodium homeostasis during maturation

“…We have already observed19 low red blood cell Na +  K + ATPase activity in patients with pseudohypoaldosteronism (PHA). The increase in red blood cell enzyme values correlated with gradual clinical improvement, reduction in salt intake, and normalisation of plasma renin activity.…”

Severe pseudohypoaldosteronism in a pair of twins not associated with hydramnios

“…Several etiologies, such as deficient renal Na + , -K + -ATPase activity [22,23], reduced number of mineralocorticoid (type I) receptors [20], and a qualitative receptor deficit [24], have been implicated. However, some of these defects may be secondary to the hyperaldosteronism or salt loss.…”