AJP - Regulatory, Integrative and Comparative Physiology, Vol 243, Issue 5 526-R530, Copyright © 1982 by American Physiological Society
Effects of aldosterone on potassium distribution
D. B. Young and T. E. Jackson
To assess the effects of long-term changes in aldosterone on potassium
distribution within the body, two groups of experiments were conducted. In
the first, seven normal dogs received continuous infusion of aldosterone at
a high physiological rate, 250 micrograms/day. Total exchangeable potassium
(Ke) and plasma potassium concentration (KP) were measured before and 4 and
6 days after aldosterone infusion. KP fell by 20% while Ke decreased by 8%
after 6 days of infusion; the ratio between extracellular and total body
potassium had been altered by the aldosterone infusion. In the second
study, 10 adrenalectomized dogs received aldosterone infusion first at 50
micrograms/day, then at 250 micrograms/day. While on each level of
aldosterone infusion, three levels of potassium intake were given by iv
infusion. When the animals were in electrolyte balance at each level of
aldosterone and potassium (after at least 7 days on each level of
infusion), Ke (expressed as meq/kg) and KP were measured. The two variables
were plotted against each other, Ke being the independent variable. Data
taken while the dogs received 50 micrograms/day aldosterone were described
by the equation, KP = 0.100Ke + 0.055, while those obtained at 250
micrograms/day were fitted by the equation, KP = 0.057Ke + 1.30. The
correlation coefficients for the two were 0.778 and 0.760, respectively.
The regressions were significantly different at a level of P less than
0.02. Data from the two groups of experiments are consistent with the
hypothesis that aldosterone alters the distribution of potassium between
the intra- and extracellular spaces, a greater portion of total potassium
being intracellular at higher levels of aldosterone.
