Plasma insulin, cholecystokinin, galanin, neuropeptide Y and leptin levels in obese women with and without type 2 diabetes mellitus

Abstract

Obesity is an important factor predisposing to type 2 diabetes mellitus, especially for postmenopausal women. Experimental studies provided evidences that leptin, cholecystokinin (CCK), galanin (GAL), neuropeptide Y (NPY) and insulin are involved in feeding behaviour. The aim of the study was to evaluate their possible relationships in obese and diabetic women.

Three groups of postmenopausal women (FSH>30 mIU/ml) were evaluated: 8 diabetic (mean age 56.6±6.9 y, BMI 29.8±5.3 kg/m²), 10 obese non-diabetic (mean age 49.6±5.4 y, BMI 36.0±3.7 kg/m²) and 12 non-diabetic controls (mean age 52.7±3.5 y, BMI 27.3±1.9 kg/m²). For each patient BMI and WHR were measured and calculated. Blood samples were collected at 8:00 a.m. after an overnight fast. Plasma concentrations of FSH, leptin, CCK, GAL, NPY and insulin were determined using commercial RIA kits.

Mean plasma NPY concentration was significantly higher in diabetic women than in controls (190.1 pg/ml±85.4 vs 120.4±36.6). Compared to controls, mean plasma leptin level was significantly higher in obese non-diabetic women (32.9 ng/ml±9.2 vs 18.9±9.1). No significant differences were found between obese non-diabetic and diabetic women.

In diabetic subjects positive correlations were found between: CCK and leptin (r=0.8295; P=0.011), CCK and insulin (r=0.7832; P=0.022), leptin and insulin (r=0.9302; P=0.001).

In obese subjects a positive correlation between WHR and GAL (r=0.6624; P=0.037) and a negative between GAL and insulin (r=−0.6795; P=0.031) were found. In controls positive correlations were found between WHR and CCK (r=0.6412; P=0.025), GAL and insulin (r=0.630; P=0.028) and negative between CCK and NPY (r=−0.6505; P=0.022).

Our results, ie higher mean plasma NPY levels in postmenopausal diabetic women and positive correlation of CCK with leptin and insulin, may suggest the role of these neuropeptides in metabolic disorders leading to type 2 diabetes mellitus.