The expression of inhibin beta B is high in human adipocytes, reduced by weight loss, and correlates to factors implicated in metabolic disease

Adipose tissue is an endocrine organ that produces and secretes adipokines. The aim of this study was to identify genes predominantly expressed in human subcutaneous adipocytes. For this purpose, an algorithm was developed and DNA microarray expression profiles from 33 human tissues and cell types were used to select genes. Inhibin beta B (INHBB; coding for the activin βB subunit) was identified and high expression in adipocytes was confirmed by real-time PCR and immunohistochemistry. INHBB expression in adipose tissue was down regulated by diet-induced weight loss (p < 0.001). Furthermore, INHBB expression was positively correlated to total (p < 0.001) and subcutaneous (p < 0.01) adipose tissue areas and serum levels of fasting insulin (p < 0.01) and cholesterol (p < 0.05). In conclusion, INHBB expression was high in human adipocytes, reduced by weight loss and adipose tissue INHBB mRNA levels correlated to metabolic risk factors. This suggests that activin B produced in adipocytes may play a role in the metabolic syndrome.