Oestrogen receptor α gene expression levels are reduced in obese compared to normal weight females

Objective: To determine whether oestrogen receptor ( ER) a messenger RNA (mRNA) levels or single nucleotide polymorphisms (SNPs) are associated with obesity in Swedish women. Design: ER alpha mRNA expression levels were measured by real-time qPCR in subcutaneous adipose tissue from non-obese (N=16, BMI < 30) and obese (N=17, BMI >= 30) women. In addition, ERa mRNA expression levels were determined in isolated adipocytes. ERa promoter usage was characterized by 50 RACE and by real-time qPCR in subcutaneous adipose tissue from the same non-obese and obese women. Two ERa SNPs were scored in 509 non-obese and 489 obese females. Results: ERa mRNA expression levels were lower in obese compared to non-obese women in both subcutaneous adipose tissue and in adipocytes. We show that two ERa promoters are differentially utilized in obese and non-obese individuals. We did not find any significant association between obesity and the ERa SNPs or haplotypes assayed. Conclusion: The reduced ERa mRNA levels observed in adipose tissue from obese compared to non-obese women support a role for oestrogen signaling via ERa, in control of body weight. Mechanistic studies of the role of ERa in adipocytes and how its expression is regulated in relation to fat mass should be performed. The latter studies should focus on the two promoters that are used differently in obese and non-obese individuals.