(P30-030-25) Sodium Retention and Distribution in Growing and Adult Rodents Fed High and Low Salt Diets

Objectives: Previous research demonstrates higher sodium retention with increasing levels of dietary salt in some populations. Our objective was to determine whole body sodium retention and sodium distribution on high and low salt diets using animal models.

Methods: Whole body retention of orally dosed Na-22, a gamma emitter, was measured in female growing and adult rats on high (3.1% by wt. of diet) and low salt (0.13% by weight of diet) diets. Sodium balance and tissue distribution was measured in adult male and female mice by ICP-OES analysis.

Results: Whole body retention of Na-22 was not different due to age of rats. Area under the curve of Na-22 retention by time was significantly lower on the high salt diet than the low salt diet. Na-22 reached background levels by day five for the rats fed a high salt diet, but rats fed a low salt diet had not excreted all of the sodium dose by day twenty three. In mice, neither sodium balance nor tissue distribution were affected by dietary salt in mice.

Conclusions: Dietary salt did not affect final sodium retention in rats, although the rate of excretion was faster on high salt diets for both young and adult female rats. Rodents may be a poor model for determining sodium metabolism in some populations.

Funding Sources: Unfunded