High dietary sodium intake increases white adipose tissue mass and plasma leptin in rats.
OBJECTIVE
Salt restriction has been reported to increase white adipose tissue (WAT) mass in rodents. The objective of this study was to investigate the effect of different sodium content diets on the lipogenic and lipolytic activities of WAT.


METHODS
Male Wistar rats were fed on normal-sodium (NS; 0.5% Na(+)), high-sodium (HS; 3.12% Na(+)), or low-sodium (LS; 0.06% Na(+)) diets for 3, 6, and 9 weeks after weaning. Blood pressure (BP) was measured using a computerized tail-cuff system. At the end of each period, rats were killed and blood samples were collected for leptin determinations. The WAT from abdominal and inguinal subcutaneous (SC), periepididymal (PE) and retroperitoneal (RP) depots was weighed and processed for adipocyte isolation, rate measurement of lipolysis and d-[U-(14)C]-glucose incorporation into lipids, glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme activity evaluation, and determination of G6PDH and leptin mRNA expression.


RESULTS
After 6 weeks, HS diet significantly increased BP; SC, PE, and RP WAT masses; PE adipocyte size; plasma leptin concentration; G6PDH activity in SC WAT; and PE depots and malic activity only in SC WAT. The leptin levels correlated positively with WAT masses and adipocyte size. An increase in the basal and isoproterenol-stimulated lipolysis and in the ability to incorporate glucose into lipids was observed in isolated adipocytes from HS rats.


CONCLUSIONS
HS diet induced higher adiposity characterized by high plasma leptin concentration and adipocyte hypertrophy, probably due to an increased lipogenic capacity of WAT.
Fonseca-Alaniz
Miriam H
MH
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, 1524 Prof Lineu Prestes Ave., 05508-900, Sao Paulo, SP, Brazil.
Brito
Luciana C
LC
Borges-Silva
Cristina N
CN
Takada
Julie
J
Andreotti
Sandra
S
Lima
Fabio B
FB
D017667:Adipocytes / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D005947:Glucose / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D020738:Leptin / Q000097:blood* / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D050155:Lipogenesis; D008066:Lipolysis; D008297:Male; D009765:Obesity / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012982:Sodium, Dietary / Q000494:pharmacology*
D020738:Leptin; D008055:Lipids; D012982:Sodium, Dietary; D005954:Glucosephosphate Dehydrogenase; D005947:Glucose