High- or low-salt diet from weaning to adulthood: effect on body weight, food intake and energy balance in rats.
OBJECTIVE
To get some additional insight on the mechanisms of the effect of salt intake on body weight.


METHODS
Rats were fed a low (LSD), normal (NSD), or high (HSD) salt diet. In a first set, body weight, tail-cuff blood pressure, fasting plasma thyroid-stimulating hormone, triiodothyronine, L-thyroxine, glucose, insulin, and angiotensin II were measured. Angiotensin II content was determined in white and brown adipose tissues. Uncoupling protein 1 expression was measured in brown adipose tissue. In a second set, body weight, food intake, energy balance, and plasma leptin were determined. In a third set of rats, motor activity and body weight were evaluated.


RESULTS
Blood pressure increased on HSD. Body weight was similar among groups at weaning, but during adulthood it was lower on HSD and higher on LSD. Food intake, L-thyroxine concentration, uncoupling protein 1 expression and energy expenditure were higher in HSD rats, while non-fasting leptin concentration was lower in these groups compared to NSD and LSD animals. Plasma thyroid-stimulating hormone decreased on both HSD and LSD while plasma glucose and insulin were elevated only on LSD. A decrease in plasma angiotensin II was observed in HSD rats. On LSD, an increase in brown adipose tissue angiotensin II content was associated to decreased uncoupling protein 1 expression and energy expenditure. In this group, a low angiotensin II content in white adipose tissue was also found. Motor activity was not influenced by the dietary salt content.


CONCLUSIONS
Chronic alteration in salt intake is associated with changes in body weight, food intake, hormonal profile, and energy expenditure and tissue angiotensin II content.
Department of Internal Medicine, Nephrology Division, Laboratory of Experimental Hypertension of the University of São Paulo School of Medicine, São Paulo, Brazil.
Michella S
MS
Coelho
Mariana D
MD
Passadore
Alessandra L
AL
Gasparetti
Theo
T
Bibancos
Patrícia O
PO
Prada
Luciene L
LL
Furukawa
Luzia N S
LN
Furukawa
Rosa T
RT
Fukui
Dulce E
DE
Casarini
Mario J A
MJ
Saad
Jacqueline
J
Luz
Silvana
S
Chiavegatto
Miriam S
MS
Dolnikoff
Joel C
JC
Heimann
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D004039:Diet, Sodium-Restricted; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D002149:Energy Intake / Q000187:drug effects* / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D006973:Hypertension / Q000178:diet therapy; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D024101:Mitochondrial Proteins; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*; D013963:Thyroid Hormones / Q000097:blood; D013997:Time Factors; D000071256:Uncoupling Protein 1; D014886:Weaning
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D017673:Sodium Chloride, Dietary; D013963:Thyroid Hormones; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D000804:Angiotensin II