Advertisement

The Calciuric Response to Dietary Salt of Dahl Salt-Sensitive and Salt-Resistant Female Rats

      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.

      KEY INDEXING TERMS

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to The American Journal of the Medical Sciences
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Massey L.K.
        • Whiting S.J.
        Dietary salt, urinary calcium, and bone loss.
        J Bone Miner Res. 1996; 11: 731-736
        • Nordin B.E.C.
        • Need A.G.
        • Morris H.A.
        • et al.
        The nature and significance of the relationship between urinary sodium and urinary calcium in women.
        J Nutr. 1993; 123: 1615-1622
        • Galletti F.
        • Ferrara I.
        • Stinga F.
        • et al.
        Effect of intravenous sodium chloride on renal sodium and calcium handling in hypertensive patients with different sensitivities to sodium chloride.
        J Hypertens. 1993; 11: S194-S195
        • Imaoka M.
        • Morimoto S.
        • Kitano S.
        • et al.
        Calcium metabolism in elderly hypertensive patients: possible participation of exaggerated sodium, calcium and phosphate excretion.
        Clin Exp Pharmacol Physiol. 1991; 18: 631-641
        • Morimoto S.
        • Imaoka M.
        • Kitano S.
        • et al.
        Exaggerated natri-calci-uresis and increased circulating levels of parathyroid hormone and 1,25-dihydroxyvitamin D in patients with senile hypertension.
        Contrib Nephrol. 1991; 90: 94-98
        • Dahl L.K.
        Salt and hypertension.
        Am J Clin Nutr. 1972; 25: 231-244
        • Dahl L.K.
        • Schackow E.
        Effects of chronic excess salt ingestion: experimental hypertension in the rat.
        Can Med Assoc J. 1964; 90: 155-160
        • Thierry-Palmer M.
        • Sherman D.D.
        • Emmett N.L.
        • et al.
        The calciuric response to dietary salt of Dahl salt-sensitive and salt-resistant male rats.
        Am J Med Sci. 2001; 321: 342-347
        • de la Sierra A.
        • del mar Lluch M.
        • Coca A.
        • et al.
        Fluid, ionic and hormonal changes induced by high salt intake in salt-sensitive and salt-resistant hypertensive patients.
        Clin Science. 1996; 91: 155-161
        • Jones G.
        Chromatographic separation of 24(R),25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3-26,23-lactone using cyano-bonded phase packing.
        J Chromatogr. 1983; 276: 69-75
        • Bligh E.G.
        • Dyer W.J.
        A rapid method of total lipid extraction and purification.
        Can J Biochem Physiol. 1959; 37: 911-917
        • Reinhardt T.A.
        • Hollis B.W.
        1,25-dihydroxyvitamin D microassay employing radioreceptor techniques.
        Methods Enzymol. 1986; 123: 176-185
        • Nordin B.E.C.
        • Polley K.J.
        Metabolic consequences of the menopause: a cross-sectional and longitudinal intervention study on 557 normal postmenopausal women.
        Calcif Tissue Int. 1987; 41: S1-S59
        • Thierry-Palmer M.
        • Carlyle K.S.
        • Williams M.D.
        • et al.
        Plasma 25-hydroxyvitamin D concentrations are inversely associated with blood pressure of Dahl salt-sensitive rats.
        J Steroid Biochem Mol Biol. 1998; 66: 255-261
        • Thierry-Palmer M.
        • Tewolde T.K.
        • Wang M.
        • et al.
        Exogenous 25-hydroxycholecalciferol does not attenuate salt-induced hypertension.
        J Steroid Biochem Mol Biol. 1998; 67: 193-199
        • Thierry-Palmer M.
        • Tewolde T.
        • Wang M.
        • et al.
        Relationship between plasma 24,25-dihydroxyvitamin D concentration and high salt intake [abstract].
        J Bone Miner Res. 1999; 14: S203
        • Castenmiller J.J.M.
        • Mensink R.P.
        • van der Heijden L.
        • et al.
        The effect of dietary sodium on urinary calcium and potassium excretion in normotensive men with different calcium intake.
        Am J Clin Nutr. 1985; 41: 52-59
        • Chan E.L.P.
        • Ho C.S.
        • MacDonald D.
        • et al.
        Interrelationships between urinary sodium, calcium, hydroxyproline and serum PTH in healthy subjects.
        Acta Endocrinol. 1992; 127: 242-245
        • Lietz G.
        • Avenell A.
        • Robins S.P.
        Short-term effects of dietary sodium intake on bone metabolism in postmenopausal women measured using urinary deoxypyridinoline excretion.
        Br J Nutr. 1997; 78: 73-82
        • McCarron D.A.
        • Rankin L.I.
        • Bennett W.M.
        • et al.
        Urinary calcium excretion at extremes of sodium intake in normal man.
        Am J Nephrol. 1981; 1: 84-90
        • Zarkadas M.
        • Gougeon-Reyburn R.
        • Marliss E.B.
        • et al.
        Sodium chloride supplementation and urinary calcium excretion in postmenopausal women.
        Am J Clin Nutr. 1989; 50: 1088-1094
        • Chan E.L.P.
        • Swaminathan R.
        Calcium metabolism and bone calcium content in normal and oophorectomized rats consuming various levels of saline for 12 months.
        J Nutr. 1998; 128: 633-639
        • Goulding A.
        • Campbell D.
        Dietary NaCl loads promote calciuria and bone loss in adult oophorectomized rats consuming a low calcium diet.
        J Nutr. 1983; 113: 1409-1414
        • Goulding A.
        • Campbell D.R.
        Effects of oral loads of sodium chloride on bone composition in growing rats consuming ample dietary calcium.
        Miner Electrolyte Metab. 1984; 10: 58-62
        • Goulding A.
        • Gold E.
        Effects of dietary NaCl supplementation on bone synthesis of hydroxyproline, urinary hydroxyproline excretion and bone 45Ca uptake in the rat.
        Horm Metab Res. 1988; 20: 743-745
        • Galletti F.
        • Rutledge A.
        • Triggle D.J.
        Influence of high sodium intake on urinary calcium excretion and cardiac calcium channels in spontaneously hypertensive rats.
        J Hypertens. 1991; 9: S366-S367
        • Wu X.
        • Ackerman U.
        • Sonnenberg H.
        Hypertension development in Dahl S and R rats on high salt-low potassium diet: calcium, magnesium and sympathetic nervous system.
        Clin Exper Hypertens. 1998; 20: 795-815
        • Wu X.
        • Vieth R.
        • Milojevic S.
        • et al.
        Regulation of sodium, calcium and vitamin D metabolism in Dahl rats on a high-salt/low-potassium diet: genetic and neural influences.
        Clin Exp Pharmacol Physiol. 2000; 27: 378-383
        • National Research Council
        Nutrient requirements of laboratory animals. 4th ed. National Academy of Sciences, Washington DC1995: 30
        • Rapp J.P.
        Development of inbred Dahl salt-sensitive and inbred Dahl salt-resistant rats.
        Hypertension. 1987; 9: I21-I23
        • Umemura S.
        • Smyth D.D.
        • Nicar M.
        • et al.
        Altered calcium homeostasis in Dahl hypertensive rats: physiological and biochemical studies.
        J Hypertension. 1986; 4: 19-26
        • Sustarsic D.L.
        • McPartland R.P.
        • Rapp J.P.
        Developmental patterns of blood pressure and urinary protein, kallikrein, and prostaglandin E2 in Dahl salt-hypertension-susceptible rats.
        J Lab Clin Med. 1981; 98: 599-606
        • Bayorh M.A.
        • Socci R.R.
        • Wang M.
        • et al.
        The role of gender in salt-induced hypertension.
        Clin Exp Hypertens. 2001; 23: 241-255