Background: Receptor-interacting protein 140 (RIP140) is a corepressor for nuclear receptors with an important role in the inhibition of energy expenditure. Postmenopausal women have increased white adipose tissue (WAT), and excessive accumulation of adipose tissue (obesity) implies a health risk. The aim of the present work was to investigate the time course of RIP140 expression in WAT during the development of ovariectomy (OVX)-induced obesity in rats.
Methods: OVX was performed in female Sprague-Dawley (SD) rats 8 weeks old. Body weight and food intake were determined once a week. WAT of sham-operated, OVX and OVX plus 17β-estradiol therapy (OVX/E2) female SD rats was weighed and used to analyse RIP140 and uncoupling protein 1 (UCP-1) expression by Western blot.
Results: Food intake and body weight were significantly increased during the 2-8 weeks after OVX. Even though body weight increased until killing, food intake progressively decreased from 9 to 16 weeks after OVX in rats. Meanwhile, increased WAT mass and decreased RIP140 expression in WAT were observed in OVX rats. In contrast, the expression of UCP-1, a key target gene of RIP140, in WAT of OVX rats was significantly higher than in sham-operated rats. All of these alterations caused by OVX were mostly reversed by the replacement of 17β-estradiol.
Conclusions: The down-regulation of RIP140 in WAT may play a compensatory role in OVX-induced obesity in rat.