Influence of obesity and menopausal status on serum leptin, cholecystokinin, galanin and neuropeptide Y levels

Obesity occurs in 60% of women after menopause and is characterized by an e xcess of adipose tissue that depends on several orexigenic (neuropeptide Y (NPY) stimulates carbohydrate ingestion, galanin stimulates fat intake) and anorectic (leptin, cholecystokinin (CCK)) factors. Both leptin and insulin can reduce hypothalamic NPY production and secretion. Behavior related to the consumption of food is probably attributed to the NPY-galanin signallin g route. We investigated basal levels of serum leptin, CCK, galanin and NPY in 16 no n-obese premenopausal women, in 15 obese premenopausal women (body mass ind ex (BMI) 34.6 +/- 1.3 SD) and in ten obese postmenopausal women (BMI 34.7 /- 1/5 SD) to determine the relationship between obesity, menopause and the se neuropeptides. Obese premenopausal women had three-fold elevations of se rum leptin (32.1 +/- 3.2 ng/ml) in comparison to non-obese premenopausal wo men (10.3 +/- 1.5 ng/ml), but similar levels to those in obese postmenopaus al women (35.3 +/- 4.1 ng/ml). In all 44 patients and in both sub-groups of premenopausal and postmenopausal women, serum leptin exhibited a strong po sitive correlation with BMI (r = 0.8692, p < 0.0001; r = 0.8803, p = 0.0001 ; r = 0.8184, p = 0.0001, respectively). Serum galanin values showed a stat istically significant increment in the obese postmenopausal group (51.1 +/- 8.1 pg/ml) compared to both premenopausal groups: the non-obese (34.9 +/- 5.8 pg/ml) and the obese (36.0 +/- 5.5 pg/ml). Non-obese menstruating women demonstrated NPY levels (175.0 +/- 12.8 pg/ml) significantly higher than t hose of obese premenopausal women (126 +/- 12.1 pg/ml) and obese postmenopa usal women (138.1 +/- 15.4 pg/ml). CCK values showed no differences between non-obese and obese pre- and postmenopausal groups. Basal insulin values w ere elevated in both obese groups compared to non-obese premenopausal women . Significantly increased leptin and galanin levels in postmenopausal obese w omen coupled with decreased NPY levels revealed some changes in the neurope ptides regulating eating behavior, which may be the reason for the onset of postmenopausal obesity.