Effect of troglitazone on tumor necrosis factor alpha and transforming growth factor beta expression and action in human adipocyte precursor cells in primary culture.

Troglitazone is a member of the class of thiazolidinediones that are known to act as insulin-sensitizing agents. Administration of these compounds ameliorates insulin resistance in type 2 diabetic patients, but may also promote weight gain. The main site of action is adipose tissue, where troglitazone binds to and activates the nuclear receptor peroxisome proliferator-activated receptor gamma2.

Effects of leptin on the differentiation and metabolism of human adipocytes.

Background: Leptin is an adipose protein regulating food intake in the hypothalamus. Animal studies have suggested that leptin also acts in an auto-/paracrine fashion on adipose cell function.

Objective: The aim of this study was to investigate the effects of leptin on the differentiation and metabolism of cultured human adipocytes.

Role of cytokines in the regulation of plasminogen activator inhibitor-1 expression and secretion in newly differentiated subcutaneous human adipocytes.

Elevated levels of plasminogen activator inhibitor-1 (PAI-1) are characteristic for obesity and are associated with increased risk of thromboembolic complications. PAI-1 recently was reported to be expressed and secreted by human adipocytes, but little is known about regulation of PAI-1 in human adipose tissue. Therefore, we examined the effects of selected cytokines present in adipose tissue on expression and secretion of PAI-1 in in vitro, differentiated subcutaneous human adipocytes in primary culture.

Effect of tumor necrosis factor alpha and transforming growth factor beta 1 on plasminogen activator inhibitor-1 secretion from subcutaneous and omental human fat cells in suspension culture.

Elevated levels of plasminogen activator inhibitor-1 (PAI-1) are characteristic of the obese state and may contribute to the association between obesity and cardiovascular disease. In this study, we measured the rate of secretion of PAI-1 antigen in isolated subcutaneous and omental abdominal adipocytes from severely obese and non-obese individuals and studied the effect of selected cytokines on PAI-1 release using a suspension culture technique. PAI-1 secretion was approximately 2-fold greater in isolated fat cells from the obese versus non-obese subjects.

Depot-specific release of leptin from subcutaneous and omental adipocytes in suspension culture: effect of tumor necrosis factor-alpha and transforming growth factor-beta1.

Objective: Leptin, the product of the ob gene, is overexpressed in human obesity and increased serum leptin levels are closely correlated with adipose tissue mass, but the regulation of leptin production is not completely understood. The aim of this study was to characterize the role of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 in depot-specific secretion of leptin from cultured human adipocytes.

Design And Methods: We measured the leptin concentrations in the culture medium of omental and subcutaneous abdominal adipocytes taken from severely obese individuals and kept in suspension culture, and studied the effect of TNF-alpha and TGF-beta1 on leptin release.