Hormonal regulation of human adipocytes at the cross-roads between obesity and hypertension.

In this issue of the journal, Gorzelniak et al. [1] examined the expression of the genes coding for the components of the renin–angiotensin system (RAS) in the subcutaneous abdominal adipocytes of 30 women, of whom 18 were obese and 10 had hypertension in combination with obesity. Compared with 12 lean women, the expression of the angiotensinogen (AGT) gene was significantly lower in the adipocytes from the 18 obese subjects. Furthermore, the renin, angiotensin II-converting enzyme and angiotensin II type-1 receptor (ATR1) genes were up-regulated in the adipocytes of 10 obese hypertensive women. Thus, Gorzelniak et al. [1] demonstrated that the RAS genes are differently expressed in adipocytes of obese and hypertensive women. Using an innovative approach, these investigators completed their clinical study with in-vitro experiments. They observed that hydrocortisone increased ATR1 gene expression in human adipocytes in a timeand dose-dependent manner, whereas hydrocortisone did not influence the expression of the other RAS genes. Furthermore, insulin, 17â-oestradiol, triiodo-Lthyronine and angiotensin II did not influence any of the RAS genes in the in-vitro experiments. The work of Gorzelniak et al. [1] is an important contribution to the existing literature, but should also be interpreted within the context of certain limitations. Although the sample size was larger than in many other reports, the Berlin group only recruited women. Furthermore, differences in age and menstrual cycle may have impacted on the findings and the study did not include lean hypertensive women.