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THE HUMAN LEUCOCYTE SODIUM PUMP IN ADRENOCORTICAL INSUFFICIENCY
Author(s) -
NG L. L.,
EVANS D. J.,
BURKE C. W.
Publication year - 1987
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1987.tb01149.x
Subject(s) - sodium , endocrinology , medicine , dexamethasone , sodium pump , incubation , intracellular , ouabain , efflux , potassium , chemistry , adrenal insufficiency , glucocorticoid , hydrocortisone , biochemistry , organic chemistry
SUMMARY In view of the known effects of Cortisol and related compounds on sodium balance, we examined leucocyte 22 Na + efflux in patients with adrenocortical insufficiency. The ouabain‐sensitive 22 Na + efflux rate constant, which reflects sodium pump activity, was lowered in secondary hypoadrenalism (mean 1.95 ± SD 0.25 vs 2.33 ± 0.45 h ‐1 , P < 0.002, n = 6). Patients with hypoadrenalism also had higher intracellular sodium content (mean 34.9 ± SD 3.5 vs 27.8 ± 9.5 mmol/kg dry weight, P < 0.008) and lower intracellular potassium to sodium ratios (mean 9.7 ± SD 0.7 vs 12.9 ± 3.6, P <0.001). These defects in cellular sodium balance were corrected following replacement therapy with Cortisol, prednisolone or dexamethasone. In‐vitro incubation of normal leucocytes with 5‐20 nmol/1 dexamethasone led to an increase in the Na + /K + ‐ATPase activity. The effect of Cortisol and related compounds on the distribution of sodium between intra‐ and extra‐cellular fluid may be mediated by their action on the sodium pump.