Experimental hyperthyroidism decreases gene expression and serum levels of adipokines in obesity.
OBJECTIVE
To analyze the influence of hyperthyroidism on the gene expression and serum concentration of leptin, resistin, and adiponectin in obese animals.


METHODS
Male Wistar rats were randomly divided into two groups: control (C)-fed with commercial chow ad libitum-and obese (OB)-fed with a hypercaloric diet. After group characterization, the OB rats continued receiving a hypercaloric diet and were randomized into two groups: obese animals (OB) and obese with 25 μg triiodothyronine (T(3))/100 BW (OT). The T(3) dose was administered every day for the last 2 weeks of the study. After 30 weeks the animals were euthanized. Samples of blood and adipose tissue were collected for biochemical and hormonal analyses as well as gene expression of leptin, resistin, and adiponectin.


RESULTS
T(3) treatment was effective, increasing fT(3) levels and decreasing fT(4) and TSH serum concentration. Administration of T(3) promotes weight loss, decreases all fat deposits, and diminishes serum levels of leptin, resistin, and adiponectin by reducing their gene expression.


CONCLUSIONS
Our results suggest that T(3) modulate serum and gene expression levels of leptin, resistin, and adiponectin in experimental model of obesity, providing new insights regarding the relationship between T(3) and adipokines in obesity.
Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, 18618-000 Botucatu, SP, Brazil. reluvizotto@yahoo.com
Renata de Azevedo Melo
Rde A
Luvizotto
André Ferreira
AF
do Nascimento
Maria Teresa
MT
de Síbio
Regiane Marques Castro
RM
Olímpio
Sandro José
SJ
Conde
Ana Paula
AP
Lima-Leopoldo
André Soares
AS
Leopoldo
Antonio Carlos
AC
Cicogna
Célia Regina
CR
Nogueira
D052242:Adiponectin / Q000097:blood*; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D006706:Homeostasis; D006980:Hyperthyroidism / Q000378:metabolism*; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D052243:Resistin / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000096:biosynthesis; D014284:Triiodothyronine / Q000096:biosynthesis
D052242:Adiponectin; D020738:Leptin; D052243:Resistin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine