Hypertension, Vol 6, 242-248, Copyright © 1984 by American Heart Association
SM Friedman
Rat tail arteries were incubated overnight in potassium (K)-free
physiological saline solution (PSS) at 10 degrees C, then returned to
normal aerated PSS at 37 degrees C for a 3-hour recovery period followed by
standard chemical analysis. Cell sodium (Na) was measured following
replacement of extracellular Na by lithium (Li) at 3 degrees C. The
addition of aldosterone at 10(-7) M reduced free cell Na by about 3 mmol/kg
dry weight (about 20%). Arginine vasopressin also lowered cell Na to the
same degree. The minimal effective dose was about 25 pM (25 pg/ml, 0.01
mU/ml), and the maximal dose was about 250 pM. No effect was seen with
higher doses (greater than 1.5 nM or 0.5 mU/ml). Tissues incubated in media
containing 10(-7) M aldosterone showed an exaggerated response to
vasopressin evidenced by a near doubling of the maximum fall in cell Na
produced by a tenfold smaller dose (25 pM). No significant change in cell K
was observed while cell water tended to increase with lower doses.
Angiotensin produced a similar reduction of cell Na at the same dose levels
as vasopressin and was similarly additive with aldosterone. We suggest that
these hormones enhance the transport of Na from luminal to basal sides of
polarized cells and from cells to environment in symmetrical cells.
ARTICLES
Additive effects of aldosterone with vasopressin or angiotensin
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