Effect of a replacement of the plasma water space on aldosterone production in the sodium-depleted rat
Debreceni, L.; Marosi, I.; Csete, B.
Acta Physiologica Academiae Scientiarum Hungaricae 41(3): 237-241
1972
ISSN/ISBN: 0001-6756 PMID: 4664460 Document Number: 45492
A total of 140 male albino rats weighing 140 to 160 g were allocated to 4 groups. A control group was given a synthetic diet containing 16 m-equiv Na/100 g and 3 groups were given a diet low in Na of peeled potato and barley containing 0.3 m-equiv Na/100 g. Dextran 40 in 5% glucose solution was injected daily into the tail vein of rats of one group on the diet low in Na to increase the plasma water space. Sham injections were given to another group on the diet low in Na. All rats were killed on day 6 of the study and the adrenals were removed for study in vitro of aldosterone and corticosterone production. Five days on a low-Na diet with or without replacement of plasma water space had no significant effect on plasma Na and K concentrations and muscle water content was the same as in control rats. Five days on a low-Na diet resulted in a significant rise in aldosterone production in all 3 groups compared with the control group. Corticosterone production was significantly less in rats on the Na-low diet when the rats were not given an infusion or a sham infusion than in the control group. There was a slight rise in corticosterone production above that of controls in rats given infusions and sham infusions on the low Na diet. It is concluded that in the rat alterations in plasma volume play no decisive role in aldosterone response to a low-Na diet.