Aims The aim of the study was to analyse the role of tumour necrosis factor‐alpha (TNF‐α) in insulin resistance and endothelial dysfunction in patients with different types of obesity.

Patients and methods Fasting serum TNF‐α immunoreactive concentration (enzyme‐linked immunosorbent assay, ELISA) and bioactivity (L929 cell cytotoxicity assay), endothelin‐1 and C‐peptide levels (radioimmunoassay, RIA) were measured in 15 patients with android‐ and 13 patients with gynoid‐type obesity and 15 lean healthy controls with normal glucose tolerance and blood pressure.

Results Significantly (P< 0.01) higher TNF‐α concentration (8.92 ± 0.44 pg/ml) and bioactivity (3.12 ± 0.48 U/ml) were found in patients with android obesity as compared to patients with gynoid obesity (7.01 ± 0.30 pg/ml, 0.97 ± 0.11 U/ml) and to the lean controls (6.88 ± 0.26 pg/ml, 0.88 ± 0.08 U/ml). Serum endothelin‐1 (5.38 ± 0.30 pg/ml) and C‐peptide levels (4.82 ± 0.71 ng/ml) were also significantly higher (P < 0.01) in patients with android‐type obesity than in controls (3.89 ± 0.43 pg/ml, 1.46 ± 0.25 ng/ml, respectively). In patients with gynoid‐type obesity, only the C‐peptide levels proved to be significantly higher (2.84 ± 0.29 ng/ml). Endothelin‐1 levels, although were found to be slightly higher, did not differ statistically from in controls (4.56 ± 0.31 pg/ml). There were significant positive linear correlations only in patients with android‐type obesity between TNF‐α, body mass index (BMI), serum endothelin‐1 and C‐peptide levels.

Conclusions TNF‐α may be one of the factors contributing to insulin resistance and vascular dysfunction in patients with android obesity.

Diabet. Med. 16, 207–211 (1999)