ABSTRACT
Background
We have shown previously that the calciuric response to salt does not differ in Dahl
salt-sensitive (S) and salt-resistant (R) male rats. Clinical studies with women,
however, suggest an effect of salt sensitivity on the calciuric response to salt.
The objective of this study was to determine whether there is an effect of salt sensitivity
on the calciuric response to salt of female S and R rats.
Method
Dahl S and R female rats were fed high- (8%) or low- (0.3%) salt diets for 3 weeks. The rats were placed in metabolic cages for 24-hour urine collection at baseline
and weekly (for sodium and calcium determination).
Results
Blood pressure of female S rats was 177±3.0 mm Hg at week 3 of high salt intake compared with 96±1 mm Hg for female R rats. Female S rats excreted significantly more calcium than female
R rats at baseline (P<0.001), when fed a nonpurified diet, and during high salt intake (P=0.004). Salt sensitivity significantly increased calcium excretion, water intake,
and urine output when rats were fed a high-salt diet. Calcium excretion, water intake,
and urine output of female S rats were time-dependent during high salt intake. Plasma
25-hydroxyvitamin D and 24,25-dihydroxyvitamin D concentrations were markedly lower
in female S rats fed a high-salt diet, but not in female R rats. Plasma parathyroid
hormone and 1,25-dihydroxyvitamin D concentrations did not significantly differ between
female S and R rats, but plasma concentrations of these two hormones at week 3 were
significantly higher in S rats fed a high-salt diet compared with S rats fed a low-salt
diet.
Conclusions
Our data indicate that the calciuric response to salt is greater in female S compared
with female R rats, thus supporting findings on the effect of salt sensitivity reported
in several clinical studies with women. The greater calciuric response to salt of
female S rats compared with female R rats, which was not seen in a previous study
when male S rats were compared to male R rats, suggest a gender difference in the
calciuric response to salt.
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Article info
Publication history
Accepted:
August 13,
2001
Received:
February 26,
2001
Footnotes
Presented in part in abstract form at the joint meeting of the American Society for Bone and Mineral Research, September 22–26, 2000, Toronto, Canada [Faqi AS, Sherman DD, Wang M, et al. The calciuric response to dietary salt of female Dahl salt-sensitive and salt-resistant rats. J Bone Miner Res 2000;13(Suppl 1):S344].
This work was supported by National Institutes of Health/Minority Biomedical Research Support Program Grant S06-GM08248, National Aeronautics and Space Administration Grant NCC9-112, and the support services of National Institutes of Health/Research Centers for Minority Institutions Grant RR03034.
Identification
Copyright
© 2001 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.
