Current diets contain an increasing amount of salt and high fructose corn syrup,
but it remains unclear as to how dietary salt and fructose affect organ function
at the molecular level. This study aimed to test the hypothesis that consumption
of high salt and fructose diets would increase tissue-specific expression of two
critical osmotically-regulated genes, nuclear factor of activated T-cells 5
(
NFAT5
) and aldose reductase (
AR
). Fifty
Sprague-Dawley rats were placed on a control, 4% NaCl, 8% NaCl, or 64% fructose
diet for eight weeks. Fourteen different tissue samples were harvested and
snap-frozen, followed by RNA purification, cDNA synthesis, and
NFAT5
and
AR
gene expression
quantification by real-time PCR.Our findings demonstrate that
NFAT5
and
AR
expression are up-regulated
in the kidney medulla, liver, brain, and adipose tissue following consumption of
a high salt diet.
NFAT5
expression is also up-regulated in the
kidney cortex following consumption of a 64% fructose diet. These findings
highlight the kidney medulla, liver, brain, and adipose tissue as being
“salt-responsive” tissues and reveal that a high fructose diet can lead to
enhanced
NFAT5
expression in the kidney cortex. Further
characterization of signaling mechanisms involved could help elucidate how these
diets affect organ function long term.