Studies have suggested a link between the transforming growth factor beta 1 (TGF-β1) signaling cascade and the stress-inducible activating transcription factor 3 (ATF3). We have demonstrated that triglyceride-rich lipoproteins (TGRL) lipolysis products activate MAP kinase stress associated JNK/c-Jun pathways resulting in up-regulation of ATF3, pro-inflammatory genes and induction of apoptosis i...

The biphasic nature of the lipolytic dose-response curve of epinephrine in fat cells from "young" rats (40-45 days) was confirmed. The first phase (Lipolysis I) occurred at concentrations of from 10(-7) m to 3 x 10(-6) m. The second phase (Lipolysis II) occurred at concentrations of from 10(-5) m to 3 x 10(-4) m. Insulin (0.1 mU/ml) abolished Lipolysis I and slightly augmented Lipolysis II. Hig...

The ability of a variety of hormones to activate cells declines with age. We have investigated the mechanism for the reduced ability of beta adrenergic stimulation to activate lipolysis in fat cells from older rats. Previously, we have found that these cells have an intact lipolytic response to a cAMP analogue but diminished cAMP accumulation after isoproterenol stimulation, suggesting that the...

BACKGROUND Free fatty acids released from adipose tissue affect the synthesis of apolipoprotein B-containing lipoproteins and glucose metabolism in the liver. Whether there also exists a reciprocal metabolic arm affecting energy metabolism in white adipose tissue is unknown. METHODS AND FINDINGS We investigated the effects of apoB-containing lipoproteins on catecholamine-induced lipolysis in ...

Isolated adipocytes from severely diabetic rats exhibited hypersensitivity to epinephrine at low concentrations (0.05-0.1 microM) on lipolysis, compared with isolated adipocytes from normal and mildly diabetic rats. Hypersensitivity to dibutyryl cyclic AMP and theophylline at concentrations from 0.05 to 0.50 mM was not observed in adipocytes of severely diabetic rats. Insulin could not exert an...

Triacylglycerol (TAG) stored in adipose tissue can be rapidly mobilized by the hydrolytic action of lipases, with the release of fatty acids (FA) that are used by other tissues during times of energy deprivation. Unlike synthesis of TAG, which occurs not only in adipose tissue but also in other tissues such as liver for VLDL formation, hydrolysis of TAG, lipolysis, predominantly occurs in adipo...

Fibrosis is the pathological accumulation of extracellular matrix and can occur in all soft tissues. In many organs, including skin, fibrosis also associated with a loss fat or lipid-filled cells. dermal adipose tissue has critical roles which are likely impacted by fibrotic remodeling. Despite identifying numerous dysregulated signaling pathways common to disease, mechanism remains poorly unde...

The mechanisms that control lipolysis in intra-abdominal fat cells from various primate species, the marmoset (Callithrix jacchus), the baboon (Papio papio), and the macaque (Macaca fascicularis), were compared to those of human intraabdominal fat cells. Selective beta 1- or beta 2-adrenoceptor agonists induced lipolysis in all species. Selective beta 3-agonists (BRL 37344, CL 316243, and SR 58...

Adiponectin is an adipokine increasing glucose and fatty acid metabolism and improving insulin sensitivity. The aim of this study was to investigate the role of adiponectin in the regulation of adipocyte lipolysis. Human adipocytes isolated from biopsies obtained during surgical operations from 16 non-obese and 17 obese subjects were incubated with 1) human adiponectin (20 microg/ml) or 2) 0.5 ...

hormone-sensitive lipase, although a role for Ca2+ in some capacity cannot be excluded. The decreased lipolysis cannot be accounted for by a diminished response to cyclic AMP, but the lack of ready reversal of the effects on lipolysis, and the lowering of cell ATP content, suggest that a large part of the effects of both EGTA and ionophore A23 187 on lipolysis may result from damage to fragile ...