Regulation of resistin by gonadal, thyroid hormone, and nutritional status.
OBJECTIVE
Resistin was recently identified as a hormone secreted by adipocytes that is under hormonal and nutritional control. This hormone has been suggested to be the link between obesity and type 2 diabetes. The aim of this study was to assess the influence of gender, gonadal status, thyroid hormones, pregnancy, and food restriction on resistin mRNA levels in adipose tissue of rats.


METHODS
We have determined resistin mRNA expression by Northern blot analysis in all experimental sets.


RESULTS
Resistin mRNA expression is influenced by age, with the highest hormone levels existing at 45 days after birth and decreasing thereafter. Resistin mRNA expression is higher in men than in women. Moreover, we studied the effect of orchidectomy and ovariectomy in rats of different ages and showed that gonadal hormones increase adipose tissue resistin mRNA expression in male rats. Resistin is also regulated by thyroid hormones; it is severely decreased in hyperthyroid rats. Our results clearly show that chronic food restriction (30% of ad libitum food intake) led to a decrease in adipose tissue mRNA levels in normal cycling female rats and pregnant rats. In pregnancy, resistin mRNA levels were enhanced particularly at midgestation.


CONCLUSIONS
Our observations indicate that resistin is influenced by gender, gonadal status, thyroid hormones, and pregnancy. These findings suggest that resistin could explain the decreased insulin sensitivity during puberty and could be the link between sex steroids and insulin sensitivity. Moreover, resistin could mediate the effect of thyroid hormones on insulin resistance and the state of insulin resistance present during pregnancy.
Nogueiras
Rubén
R
Department of Physiology, Universitario de Santiago, Santiago de Compostela, Spain.
Gualillo
Oreste
O
Caminos
J Eduardo
JE
Casanueva
Felipe F
FF
Diéguez
Carlos
C
D000273:Adipose Tissue / Q000737:chemistry; D000375:Aging; D000818:Animals; D001835:Body Weight; D005260:Female; D005786:Gene Expression Regulation; D006729:Hormones, Ectopic / Q000235:genetics*; D008297:Male; D020932:Nerve Growth Factor; D009748:Nutrition Disorders / Q000378:metabolism; D009752:Nutritional Status; D009919:Orchiectomy; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D011247:Pregnancy; D011506:Proteins; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin; D013737:Testis / Q000502:physiology*; D013963:Thyroid Hormones / Q000502:physiology*
D006729:Hormones, Ectopic; D011506:Proteins; D012333:RNA, Messenger; D052243:Resistin; C499622:Retn protein, rat; C486575:Retnla protein, rat; D013963:Thyroid Hormones; D020932:Nerve Growth Factor