Endocrine Abstracts

Objectives: To investigate whether there is a sex difference in serum leptin concentration in Chinese Type 2 diabetic patients with and without nephropathy.

Methods: Early morning fasting serum leptin concentrations were measured in 34 Type 2 diabetic patients (mean age 62.1) with nephropathy (creatinine 120-450micromol/l and spot urinary albumin creatinine ratio (ACR) > 25 mg/mmol), 12 newly diagnosed diabetic subjects (mean age 62.5) with normoalbuminuria (spot urinary ACR <3.5 mg/mmol and creatinine < 120micromol/l) and 34 age-matched non-diabetic controls (mean age 65.9).

Results: All 3 groups had similar age, body mass index (BMI), total cholesterol, low-density lipoprotein cholesterol and blood pressure. Serum leptin concentration was significantly higher in patients with diabetic nephropathy than non-diabetic controls (17.5 +/- 16.8 vs 9.1 +/- 7.1, p<0.001). There was no significant difference in leptin concentrations between diabetic patients with nephropathy and those without nephropathy (17.5 +/- 16.8 vs 14.6 +/- 10.5, p=1.0) or between normoalbuminuric diabetic patients and non-diabetic controls (14.6 +/- 10.5 vs 9.1 +/- 7.1, p=0.61). Serum leptin concentration was significantly higher in non-diabetic women than men (12.5 +/- 7.3 vs 4.2 +/- 2.0, p=0.001) while there was no significant difference between women and men in patients with diabetic nephropathy (18.6 +/- 17.0 vs 16.8 +/- 17.0, p=0.754) or in patients without nephropathy (18.9 +/- 11 vs 8.6 +/- 5.9, p=0.071). On multivariate analysis, ACR (Beta=0.411, p<0.001) and BMI (Beta=0.240, p=0.002) were independently associated with leptin (R2=0.194, F=22.1, p<0.001). ACR (Beta=0.370, p=0.044) was the only determinant of leptin (R2=0.137, F=11.4, p=0.044) in the diabetic nephropathy group.

Conclusions: The regulation of leptin metabolism is different between men and women regardless of diabetes status. This difference is abolished by diabetic nephropathy. Men with diabetic nephropathy may be may exhibit greater leptin resistant than diabetic men without nephropathy and non-diabetic men independently of body weight.