[The Integration and Regulation of Hormone-Sensitive Lipase in Reproductive System].

Hormone-sensitive lipase (HSL) has long been considered as a classical rate-limiting enzyme during lipolysis since it was first described in 1960s. HSL is regulated mainly by catecholamine, including adrenalin. Studies in recent years indicated that the substrates for HSL are not only triglycerides, but also diacylglycerol with the catalytic activity is ten times that of triglycerides, glycerol esters and cholesterol esters, which overthrow the opinion that HSL is specific to triglyceride.

Increase or decrease hydrogen sulfide exert opposite lipolysis, but reduce global insulin resistance in high fatty diet induced obese mice.

Objective: Adipose tissue expressed endogenous cystathionine gamma lyase (CSE)/hydrogen sulfide (H2S) system. H2S precursor inhibited catecholamine stimulated lipolysis. Thus, we hypothesized that CSE/H2S system regulates lipolysis which contributed to the pathogenesis of insulin resistance.

[A new methods for determining hydrogen sulfide release in cultured cells].

Objective: To establish a simple method of measuring hydrogen sulfide (H2S) in cultured living cells.

Methods: Filtration membrane was stuck on the lid of cell culture plate. H2S released from cultured cells was trapped by zinc acetate to generate ZnS deposition.

[Modified methylene blue method for measurement of hydrogen sulfide level in plasma].

In past decade, hydrogen sulfide (H₂S) as a novel gasotransmitter, covered many fields in biological and medical research. However, there is no effective, convenient and high-throughput method for determination of circulatory H₂S until now. Here, we aim to develop an easy method for measurement of circulatory H₂S by modified methylene blue method.

Pig large tumor suppressor 2 (Lats2), a novel gene that may regulate the fat reduction in adipocyte.

Clenbuterol, a Beta(2)-adrenoceptor agonist, has been proven to be a powerful repartition agent that can decrease fat deposition. Based on results from our previous cDNA microarray experiment of pig clenbuterol administration, a novel up-regulated EST was full-length cloned (4859 bp encoding 1041 amino acids) and found to be the pig homolog of large tumor suppressor 2 (Lats2). We mapped pig Lats2 to chromosome 11p13-14 by using FISH, and western blotting demonstrated that pig Lats2 protein was most abundant in adipose.

Perilipin gene 1237 T > C polymorphism is not associated with obesity risk in northern Chinese Han adults.

Objective: To identify the association between PLIN 1237 polymorphism and obesity in Chinese Han adults.

Methods: A total of 994 adults (157 obese subjects, 322 overweight subjects, and 515 normal controls) were recruited from two rural communities. PLIN 1237 polymorphism was genotyped by polymerase chain reaction-restriction-fragment-length-polymorphism (PCR-RFLP).

[Glucocorticoids, adipose metabolism and insulin resistance].

Obesity, insulin resistance, and type 2 diabetes are associated with elevated concentration of circulating free fatty acid (FFA), which is critically governed by the process of triglyceride lipolysis in adipocytes. Endogenous and exogenous glucocorticoids excess could induce insulin resistance and diabetes. Thus, the effects of glucocorticoids stimulating adipose lipolysis and elevating FFA release may contribute to glucocorticoids-induced insulin resistance and diabetes.

[Tumor necrosis factor-alpha upregulates the protein levels of adipose differentiation-related protein in rat differentiated adipocytes].

Objective: To investigate the effect and basis of tumor necrosis factor-alpha (TNF-alpha) on the lipid droplet associating protein adipose differentiation-related protein(ADRP) in rat differentiated adipocytes.

Methods: Differentiated rat adipocytes derived from epididymal fat pads of Sprague-Dawley rats were incubated in the presence or absence of TNF-alpha (25 microg/L). Glycerol level released in the culture medium was determined by a colorimetric assay and served as an index of lipolysis.

[The mechanisms of stimulated lipolysis by high concentration of glucose in primary rat adipocytes].

Objective: To investigate the cellular mechanisms of adipocyte lipolytic response to a high concentration of glucose, which liberates free fatty acids (FFA) efflux from adipose cells to plasma.

Methods: Adipocytes were isolated from epididymal fat pads of Sprague-Dawley (SD) rats, and were incubated in the presence or absence of excess glucose (25 mmol/L). Glycerol released in the culture medium was determined by use of a colorimetric assay and served as an index of lipolysis.

[Adipose triglyceride lipase regulates adipocyte lipolysis].

Obesity, insulin resistance, and type 2 diabetes are associated with elevated concentration of circulating free fatty acids (FFAs), which are critically governed by the process of triglyceride lipolysis in adipocytes. Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) are two major enzymes in the control of triacylglycerol hydrolysis in adipose tissue. ATGL expressed predominantly in white adipose tissue specifically initiates triacylglycerol hydrolysis to generate diacylglycerols and FFA, a role distinguished from HSL that mainly hydrolyzes diacylglycerols.

[Perilipin associated with lipid droplets regulates lipolysis].

Perilipins are the proteins associating with the lipid droplets in adipocytes and steroidogenic cells. Unphosphorylated perilipins coat the surface of intracellular lipid droplets to form a barrier that prevents lipase from accessing to triacylglycerol core, thus suppressing lipolysis. Upon activation of protein kinase A (PKA), two proteins, hormone-sensitive lipase (HSL) and perilipins, are phosphorylated.

[Function of PAT family proteins in the lipid metabolism].

Triglycerides are stored in intracellular lipid droplets in mammalian cells. Current evidences suggest that the intracellular lipid droplets are active participants in a variety of metabolic processes, and thus are considered as functional organelles in cells. The lipid droplet is composed of a triglyceride core surrounded by a phospholipid monolayer in which several proteins are embedded.