BACKGROUND Retinol-binding protein 4 (RBP4) may play an important role in the origin of insulin resistance and metabolic syndrome. Few prospective data are available on the relationship between RBP4 and coronary heart disease (CHD). Furthermore, previous studies did not distinguish among full-length and truncated forms of RBP4 that might have various biological activities. METHODS AND RESULTS...

Overweight and obesity are the leading causes for the development of multiple adverse metabolic effects. Retinol Binding Protein 4 (RBP4), a peptide secreted from adipocytes and hepatocytes, provides a new link between obesity and insulin resistance. The objective of this work is to determine RBP4 serum levels and evaluate its relationship with serum testosterone (T), serum estradiol (E2), E2/T...

Retinoids are vitamin A (retinol) derivatives and complex regulators of adipogenesis by activating specific nuclear receptors, including the retinoic acid receptor (RAR) and retinoid X receptor (RXR). Circulating retinol-binding protein 4 (RBP4) and its membrane receptor STRA6 coordinate cellular retinol uptake. It is unknown whether retinol levels and the activity of RAR and RXR in adipocyte p...

BACKGROUND/AIMS Pioglitazone, a peroxisome proliferator-activated receptor γ activator, is clinically used to treat insulin resistance. However, the underlying mechanism of pioglitazone's action remains unclear. We investigated whether, and how, pioglitazone modulates serum level of retinol binding protein 4 (RBP4), an adipocytokine associated with obesity and insulin resistance. METHODS Insu...

BACKGROUND Chronic heart failure is associated with higher risk for developing diabetes mellitus. Secretory products from adipocytes may contribute to the deterioration in glycemic control and increased insulin resistance (IR). Retinol binding protein 4 (RBP4) is an adipose tissue-derived protein with pro-diabetogenic effects. The aim of the present study was to investigate the relationship of ...

The cellular uptake of vitamin A from its RBP4-bound circulating form (holo-RBP4) is a homeostatic process that evidently depends on the multidomain membrane protein STRA6. In humans, mutations in STRA6 are associated with Matthew-Wood syndrome, manifested by multisystem developmental malformations. Here we addressed the metabolic basis of this inherited disease. STRA6-dependent transfer of ret...

Insulin resistance occurs under conditions of obesity, metabolic syndrome, and type 2 diabetes. It was found to be accompanied by down-regulation of the insulin-responsive glucose transporter GLUT4. Decreased adipocyte GLUT4 caused secretion by adipocytes of the serum retinol-binding protein RBP4. Enhanced levels of serum RBP4 appeared to be the signal for the development of systemic insulin re...

Obesity is now considered as a convincing and probable cause for colorectal neoplasia (World Cancer Research Fund 2011). Insulin resistance is a key mechanism relating obesity to colon carcinogenesis (Giovannucci 2001). Supporting evidence for this notion includes data from a number of epidemiological studies demonstrating the risk association of colon cancer and adenoma with insulin resistance...

BACKGROUND The interplay between the novel adipokine retinol-binding protein-4 (RBP4) and coronary artery disease (CAD) is still obscure. We investigated the relationship between RBP4 levels and the presence and severity of angiographically proven CAD and determined its possible role in acute myocardial infarction (AMI). METHODS 305 individuals with angiographically proven CAD (CAD-patients),...

BACKGROUND Insulin resistance (IR) is closely correlated with cardiovascular disease (CVD). Retinol-binding protein 4 (RBP4) is a novel adipokine that modulates the action of insulin in various diseases. This study addressed the relationship between RBP4 and IR in newly diagnosed essential hypertension. METHODS Serum RBP4, anthropometric and metabolic parameters were determined in 267 newly d...