Is cortisol involved in upper-body obesity?

The hypothalamic-pituitary-adrenal axis in obesity

The hypothalamic-pituitary-adrenal (HPA) axis normally maintains the concentration of cortisol within a narrow range with a diurnal variation characterized by higher cortisol concentrations in the morning and reduced levels in the evening. Excessive or deficient secretion of cortisol is associated with pathologic changes. Obesity has been linked with age, sex and racial alterations in the functioning of the HPA axis which are reviewed. The possible relationship of altered HPA axis activity with the long-term complications of obesity are considered.

Metabolic abnormalities linked to obesity: effects of dexfenfluramine in the corpulent rat

The JCR:LA-corpulent rat is a useful experimental model for the obese-diabetic-dyslipidemic syndrome that mimics the human condition and exhibits spontaneous development of atherosclerosis and myocardial lesions. A 30-day treatment of 6-month-old rats with dexfenfluramine 1, 2.5, and 5 mg per kilogram decreased body weight through loss of adipose tissue mass. The effect is caused primarily by the ability of dexfenfluramine to reduce food intake. The maximum depression of food intake and greatest weight loss is seen during the first 10 days of treatment in this experimental model; thereafter, body weight stabilizes. However, during this period, there is a marked decrease in serum concentrations of triglycerides, cholesterol, and insulin. Corpulent male rats were also treated from 6 to 37 weeks of age with dexfenfluramine 2.5 mg/kg. This also produces a sustained decrease in body weight and a decrease in circulating insulin concentrations. Preliminary evidence demonstrates a substantial decrease in the incidence of necrotic myocardial lesions produced by ischemic events. This study establishes that dexfenfluramine treatment can decrease the severity of associated risk factors for cardiovascular disease, namely obesity, diabetes, and dyslipidemias. Furthermore, we report the first evidence that long-term treatment with dexfenfluramine can largely prevent the occurrence of myocardial lesions and end-stage cardiovascular disease in this animal model prone to atherosclerosis.

Central adiposity and increased risk of coronary artery disease mortality in older women

The relation between central adiposity, measured by the waist/hip circumference ratio (WHR), and 4-year risk of fatal coronary artery disease was examined in a large cohort (n = 32,898) of women aged 55 to 69 years. The age-adjusted relative risk of death from coronary artery disease (115 deaths) was 3.3 for women in the highest tertile of WHR compared to the lowest tertile (95% confidence interval: 2.0, 5.6). After adjustment for age, body mass, smoking, physical activity, estrogen use, marital status, and alcohol intake, the relative risk of coronary death for women in the middle and highest tertiles versus those in the lowest tertile of WHR were 1.3 and 2.8, respectively (P for linear trend < 0.001). Further adjustment for hypertension and diabetes mellitus reduced the estimates slightly to 1.2 and 2.0, but the trend in relative risk remained statistically significant (P = 0.03). In contrast, body mass index showed no independent association with coronary death. Hypertension, diabetes mellitus, cigarette smoking, estrogen nonuse, and being unmarried were significant predictors of greater risk of coronary death in the multivariate model. These results indicate that central adiposity, reflected by an increased WHR, is an important risk factor for death from coronary artery disease in women, most of whom were postmenopausal. The association of central adiposity with risk of coronary death is independent, for the most part, of its association with hypertension and diabetes.