Henry Kvist

Visceral fat accumulation in men is positively associated with insulin, glucose, and C-peptide levels, but negatively with testosterone levels

Twenty-three healthy men (age 25 to 50 years), covering a wide range of fatness and body fat distribution, were studied. An oral glucose tolerance test was performed and adipose tissue areas were calculated from computed tomography (CT) scans made at the level of L4/L5. Visceral fat area was associated with elevated concentrations of insulin and C-peptide and with glucose intolerance before and after the oral glucose load. Concentrations of sex-hormone-binding globulin (SHBG), as well as total and free testosterone, were negatively correlated with waist/hip circumference ratio and visceral fat area and also negatively associated with increased glucose, insulin, and C-peptide concentrations. In multiple linear regression, adjusting for age, body mass index, and visceral fat area, serum concentrations of free testosterone were still negatively correlated with glucose, insulin, and C-peptide levels. Without claiming any causality in the observed associations, we conclude that, unlike in women, abdominal fat distribution, insulin, glucose, and C-peptide levels are negatively associated with serum testosterone levels in men.

The morphology and metabolism of intraabdominal adipose tissue in men

Mass, morphology, and metabolism of total adipose tissue and its subcutaneous, visceral, and retroperitoneal subcompartments were examined in 16 men with a wide variation of total body fat. Computerized tomography (CT) scans showed that the intraabdominal fat mass comprised approximately 20% of total fat mass. Visceral and retroperitoneal fat masses were approximately 80% and 20% of total intraabdominal fat mass, respectively. Enlargement of intraabdominal fat depots was due to a parallel adipocyte enlargement only. Direct significant correlations were found between these adipose tissue masses and blood glucose and plasma insulin levels, blood pressure, and liver function tests, while glucose disposal rate during euglycemic glucose clamp measurements at submaximal insulin concentrations (GDR), plasma testosterone, and sex hormone-binding globulin concentrations correlated negatively. The correlations for glucose, insulin, and GDR were strongest with visceral fat mass. Adipose tissue lipid uptake, measured after oral administration of labeled oleic acid in triglyceride, was approximately 50% higher in omental than in subcutaneous adipose tissues. Adipocytes from omental fat also showed a higher lipolytic sensitivity and responsiveness to catecholamines. Furthermore, these adipocytes were less sensitive to the antilipolytic effects of insulin. Both lipid uptake and lipolytic sensitivity and responsiveness showed strong correlations (r = 0.8 to 0.9) to blood glucose and plasma insulin concentrations and also to the GDR (negative), while no such correlations were found with lipid uptake in subcutaneous or retroperitoneal abdominal adipose tissues. Taken together, these results suggest a higher turnover of lipids in visceral than in the other fat depots, which is closely correlated to systemic insulin resistance and glucose metabolism in men.

Distribution of adipose tissue and muscle mass in alcoholic men.

An elevated waist to hip ratio (WHR) has been found to be a predictor for several prevalent diseases. To examine the potential role of alcohol in the elevation of WHR, established alcoholic men without severe liver damage who were in adequate nutritional condition were compared with organized teetotalers matched for age, height, and body weight; the groups had similar total body fat content and lean body mass. Computed tomographic (CT) measurements at thigh and trunk levels showed a significant increase in the visceral adipose tissue (AT) areas and a slight decrease of muscle areas in the gluteal and femoral regions of the alcoholics. The alcoholic men had 48% of their AT areas of trunk scans localized retroperitoneally and intraperitoneally compared with 38% for the teetotalers (P < .01). The difference seemed to be more marked for retroperitoneal than for intraperitoneal AT (97 v 60 cm2, P < .01). The elevated visceral AT areas seemed to be independent of smoking. It was concluded that the increased WHR of alcoholics may include not only changes in AT, but also in muscle tissue distribution.