Kaliuretic response to aldosterone: influence of the content of potassium in the diet.
The excretion of potassium (K+) decreased by 50% (30 v 63 mEq/d, P < .01) when subjects consumed a diet that was low in K+ for 3 days. Although part of this conservation of K+ was achieved in part by suppressing the release of aldosterone, nevertheless providing exogenous mineralocorticoids did not lead to a large kaliuresis when there was a modest degree of K+ depletion. Accordingly, the purpose of this study was to evaluate possible mechanisms for this antikaliuretic response to mineralocorticoids. The renal handling of K+ was examined by independent analysis of the two factors that influence its excretion, the driving force to secrete K+ and the urine volume. This driving force is reflected in a noninvasive fashion by the transtubular [K+] gradient (TTKG). Stimuli to increase the rate of excretion of K+ in subjects on a normal and a low-K+ diet included the administration of 200 micrograms fludrocortisone (9 alpha F), the induction of a high urine flow rate (9 alpha F+furosemide), the induction of bicarbonaturia (9 alpha F+acetazolamide), and the excretion of Cl(-)-poor urine (< 15 mEq/L). On the low-K+ diet, the peak value for the TTKG 3 to 4 hours after 9 alpha F was less than half that while on the normal diet (6.4 v 14, P < 0.01). In contrast, the TTKG was not significantly different on either diet when there was bicarbonaturia or the excretion of a Cl(-)-poor urine (18 v 17 and 17 v 16, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Vasuvattakul
S
S
Quaggin
S E
SE
Scheich
A M
AM
Bayoumi
A
A
Goguen
J M
JM
Cheema-Dhadli
S
S
Halperin
M L
ML
D000086:Acetazolamide / Q000494:pharmacology; D000328:Adult; D000450:Aldosterone / Q000378:metabolism*; D005260:Female; D005438:Fludrocortisone / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D007668:Kidney / Q000502:physiology*; D008297:Male; D011188:Potassium / Q000652:urine*; D011191:Potassium Deficiency / Q000503:physiopathology / Q000652:urine*; D017419:Potassium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D013997:Time Factors
D017419:Potassium, Dietary; D000450:Aldosterone; D005665:Furosemide; D000086:Acetazolamide; D011188:Potassium; D005438:Fludrocortisone