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PubMed2002

Hormone-sensitive lipase deficiency in mice causes lipid storage in the adrenal cortex and impaired corticosterone response to corticotropin stimulation.

Hormone-sensitive lipase (HSL, E.C.3.1.1.3, gene designation Lipe) is reportedly the major cholesteryl esterase of adrenal cortex. Because of the potential importance of cholesteryl ester hydrolysis in steroidogenesis, gene-targeted HSL-deficient mice were assessed for adrenal cortical morphology and function. Compared with control animals, HSL deficiency results in a marked accumulation of lipid droplets both in zona glomerulosa and zona fasciculata. In the zona fasciculata, lipid accumulation was observed progressively from the outer to the inner regions, culminating near the corticomedullary junction with the formation of syncytial-lipoid structures having the appearance of degenerative cells. These morphological changes did not significantly alter the basal levels of circulating corticosterone, but following ACTH stimulation, corticosterone levels were decreased (P < 0.001). The observation of normal basal corticosterone and aldosterone levels demonstrates that some free cholesterol for steroid synthesis can be produced independently of HSL. Taken together, these results indicate that HSL-deficient mice accumulate lipid droplets in such a way as to impair acute ACTH stimulation of corticosterone secretion. Such observations are also found in some forms of congenital adrenal hyperplasia. By extension, HSL deficiency may be a cause of hereditary adrenocortical hypofunction in humans.

Adrenal Cortex↗
PubMed1998

Identification of genetic variation in the human hormone-sensitive lipase gene and 5' sequences: homology of 5' sequences with mouse promoter and identification of potential regulatory elements.

Hormone-sensitive lipase (HSL) plays a crucial role in triglyceride hydrolysis in adipose tissue and exhibits cholesterol hydrolase activity in steroidogenic tissue and macrophages. Thus, common genetic variation in the HSL gene could affect both energy metabolism and atherogenesis. Using overlapping single-strand conformational polymorphism analysis (SSCP), a common single base change (T/C) in intron 4 [allele frequency 0.012 (95% CI 0.007-0. 018)] and a variable CA repeat in intron 6 with 9 alleles (heterozygosity index = 0.66) were identified. Sequence of 1.123 kb upstream from the reported 5'UTR (1) which includes intron B, exon B, and 159 bp of the promoter (2) was obtained and a single common nucleotide change, -60C/G [allele frequency 0.052 (95% CI 0.039-0. 064)], identified. Preliminary in vitro studies show that the -60G construct has 38.5% lower luciferase activity compared to the -60C construct (P = 0.035), suggesting a functional change affecting HSL gene expression. The 5' sequence shows 57-59% homology with the mouse promoter with higher homology at potential regulatory motifs. Thus, the 1.7 kb of 5' sequences is well conserved and may play a part in the regulation of HSL gene expression.

Adipocytes↗
PubMed2006

The hormone-sensitive lipase C-60G promoter polymorphism is associated with increased waist circumference in normal-weight subjects.

OBJECTIVE: Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from triglyceride stores in adipocytes. The aim of the present study was to investigate the role of the HSL gene promoter variant C-60G, a polymorphism which previously has been associated with reduced promoter activity in vitro, in obesity and type 2 diabetes. DESIGN: We genotyped two materials consisting of obese subjects and non-obese controls, one material with offspring-parents trios, where the offspring was abdominally obese and one material with trios, where the offspring had type 2 diabetes or impaired glucose homeostasis. HSL promoter containing the HSL C-60G G-allele was generated and tested against a construct with the C-allele in HeLa cells and primary rat adipocytes. HSL mRNA levels were quantified in subcutaneous and visceral fat from 33 obese subjects. RESULTS: We found that the common C-allele was associated with increased waist circumference and WHR in lean controls, but there was no difference in genotype frequency between obese and non-obese subjects. There was a significant increased transmission of C-alleles to the abdominally obese offspring but no increased transmission of C-alleles was observed to offspring with impaired glucose homeostasis. The G-allele showed reduced transcription in HeLa cells and primary rat adipocytes. HSL mRNA levels were significantly higher in subcutaneous compared to visceral fat from obese subjects. CONCLUSION: The HSL C-60G polymorphism is associated with increased waist circumference in non-obese subjects.

Adult↗
PubMed1993

Gene organization and primary structure of human hormone-sensitive lipase: possible significance of a sequence homology with a lipase of Moraxella TA144, an antarctic bacterium.

The human hormone-sensitive lipase (HSL) gene encodes a 786-aa polypeptide (85.5 kDa). It is composed of nine exons spanning approximately 11 kb, with exons 2-5 clustered in a 1.1-kb region. The putative catalytic site (Ser423) and a possible lipid-binding region in the C-terminal part are encoded by exons 6 and 9, respectively. Exon 8 encodes the phosphorylation site (Ser551) that controls cAMP-mediated activity and a second site (Ser553) that is phosphorylated by 5'-AMP-activated protein kinase. Human HSL showed 83% identity with the rat enzyme and contained a 12-aa deletion immediately upstream of the phosphorylation sites with an unknown effect on the activity control. Besides the catalytic site motif (Gly-Xaa-Ser-Xaa-Gly) found in most lipases, HSL shows no homology with other known lipases or proteins, except for a recently reported unexpected homology between the region surrounding its catalytic site and that of the lipase 2 of Moraxella TA144, an antarctic psychrotrophic bacterium. The gene of lipase 2, which catalyses lipolysis below 4 degrees C, was absent in the genomic DNA of five other Moraxella strains living at 37 degrees C. The lipase 2-like sequence in HSL may reflect an evolutionarily conserved cold adaptability that might be of critical survival value when low-temperature-mobilized endogenous lipids are the primary energy source (e.g., in poikilotherms or hibernators). The finding that HSL at 10 degrees C retained 3- to 5-fold more of its 37 degrees C catalytic activity than lipoprotein lipase or carboxyl ester lipase is consistent with this hypothesis.

Adipose Tissue↗
PubMed1999

Domain identification of hormone-sensitive lipase by circular dichroism and fluorescence spectroscopy, limited proteolysis, and mass spectrometry.

Structure-function relationship analyses of hormone-sensitive lipase (HSL) have suggested that this metabolically important enzyme consists of several functional and at least two structural domains (Osterlund, T., Danielsson, B., Degerman, E., Contreras, J. A., Edgren, G., Davis, R. C., Schotz, M. C., and Holm, C. (1996) Biochem. J. 319, 411-420; Contreras, J. A., Karlsson, M., Osterlund, T., Laurell, H., Svensson, A., and Holm, C. (1996) J. Biol. Chem. 271, 31426-31430). To analyze the structural domain composition of HSL in more detail, we applied biophysical methods. Denaturation of HSL was followed by circular dichroism measurements and fluorescence spectroscopy, revealing that the unfolding of HSL is a two-step event. Using limited proteolysis in combination with mass spectrometry, several proteolytic fragments of HSL were identified, including one corresponding exactly to the proposed N-terminal domain. Major cleavage sites were found in the predicted hinge region between the two domains and in the regulatory module of the C-terminal, catalytic domain. Analyses of a hinge region cleavage mutant and calculations of the hydropathic pattern of HSL further suggest that the hinge region and regulatory module are exposed parts of HSL. Together, these data support our previous hypothesis that HSL consists of two major structural domains, encoded by exons 1-4 and 5-9, respectively, of which the latter contains an exposed regulatory module outside the catalytic alpha/beta-hydrolase fold core.

Animals↗
PubMed2003

Glucose ingestion blunts hormone-sensitive lipase activity in contracting human skeletal muscle.

To examine the effect of attenuated epinephrine and elevated insulin on intramuscular hormone sensitivity lipase activity (HSLa) during exercise, seven men performed 120 min of semirecumbent cycling (60% peak pulmonary oxygen uptake) on two occasions while ingesting either 250 ml of a 6.4% carbohydrate (GLU) or sweet placebo (CON) beverage at the onset of, and at 15 min intervals throughout, exercise. Muscle biopsies obtained before and immediately after exercise were analyzed for HSLa. Blood samples were simultaneously obtained from a brachial artery and a femoral vein before and during exercise, and leg blood flow was measured by thermodilution in the femoral vein. Net leg glycerol and lactate release and net leg glucose and free fatty acid (FFA) uptake were calculated from these measures. Insulin and epinephrine were also measured in arterial blood before and throughout exercise. During GLU, insulin was elevated (120 min: CON, 11.4 +/- 2.4, GLU, 35.3 +/- 6.9 pM, P < 0.05) and epinephrine suppressed (120 min: CON, 6.1 +/- 2.5, GLU, 2.1 +/- 0.9 nM; P < 0.05) compared with CON. Carbohydrate feeding also resulted in suppressed (P < 0.05) HSLa relative to CON (120 min: CON, 1.71 +/- 0.18, GLU, 1.27 +/- 0.16 mmol.min-1.kg dry mass-1). There were no differences in leg lactate or glycerol release when trials were compared, but leg FFA uptake was lower (120 min: CON, 0.29 +/- 0.06, GLU, 0.82 +/- 0.09 mmol/min) and leg glucose uptake higher (120 min: CON, 3.16 +/- 0.59, GLU, 1.37 +/- 0.37 mmol/min) in GLU compared with CON. These results demonstrate that circulating insulin and epinephrine play a role in HSLa in contracting skeletal muscle.

Carbohydrate Metabolism↗
PubMed2003

Expression of human hormone-sensitive lipase in white adipose tissue of transgenic mice increases lipase activity but does not enhance in vitro lipolysis.

Hormone-sensitive lipase (HSL) catalyzes the hydrolysis of acylglycerols and cholesteryl esters (CEs). The enzyme is highly expressed in adipose tissues (ATs), where it is thought to play an important role in fat mobilization. The purpose of the present work was to study the effect of a physiological increase of HSL expression in vivo. Transgenic mice were produced with a 21 kb human genomic fragment encompassing the exons encoding the adipocyte form of HSL. hHSL mRNA was expressed at 3-fold higher levels than murine HSL mRNA in white adipocytes. Transgene expression was also observed in brown adipose tissue (BAT) and skeletal muscle. The human protein was detected in ATs of transgenic (Tg) mice. The hydrolytic activities against triacylglycerol (TG), diacylglycerol (DG) analog, and CE were increased in transgenic mouse AT. However, cAMP-inducible adipocyte lipolysis was lower in transgenic animals. In the B6CBA genetic background, transgenic mice up to 14 weeks of age showed lower body weight and fat mass. The phenotype was not observed in older animals and in mice fed a high-fat diet (HFD). In the OF1 genetic background, there was no difference in fat mass of mice fed ad libitum. However, transgenic mice became leaner than their wild-type (WT) littermates after a 4 day calorie restriction. The data show that overexpression of HSL, despite increased lipase activity, does not lead to enhanced lipolysis.

Adipose Tissue↗
PubMed1993

Detection of hormone-sensitive lipase in various tissues. I. Expression of an HSL/bacterial fusion protein and generation of anti-HSL antibodies.

Hormone-sensitive lipase (HSL) is an intracellular neutral lipase found in a variety of tissues, but primarily in adipose and steroidogenic tissues, that hydrolyzes triglycerides and cholesteryl esters. In the present studies, a portion of rat HSL cDNA was subcloned into a pET expression system and the resulting recombinant fusion protein was over-expressed in E. coli. The approximately 26 kD HSL/fusion protein was used to generate polyclonal antibodies in rabbits that recognize intact HSL (84 kD) in rat adipose tissue, ovary, adrenal, testis, heart, and lung, as well as in human adipose tissue. In addition, there was an approximately 89 kD protein observed in all rat tissues expressing the 84 kD protein. Unique to testes, there was an immunoreactive protein of approximately 102 kD in sexually immature rats, and additional immunoreactive proteins of approximately 113 kD and approximately 127 kD in sexually mature rats. The anti-HSL/fusion protein antibodies could remove approximately 60-80% of total neutral cholesterol esterase activity from extracts of rat adipose tissue and immunoprecipitated a single 84 kD protein after labeling of adipocytes with [32P]orthophosphate. The incorporation of 32P into the 84 kD HSL protein was stimulated 4-fold by incubation of adipocytes with isoproterenol. The half life of [35S]methionine-labeled HSL was approximately 4 h in normal rat adipocytes. The production of an HSL/fusion protein and generation of antibodies that recognize native HSL should be valuable tools in exploring the mechanisms regulating the expression of HSL activity and the function and localization of its immunoreactive proteins.

Adipose Tissue↗
PubMed1978

Animal models of the hormone-sensitive and -insensitive prostatic adenocarcinomas, Dunning R-3327-H, R-3327-HI, and R-3327-AT.

The Dunning R-3327-H is a well-differentiated transplantable rat prostatic adenocarcinoma that contains both hormone-sensitive and -insensitive cells. The component composed of hormone-insensitive cells has been permitted to grow in a castrated male, and a new slow-growing, well-differentiated hormone-insensitive subline of the tumor has been established and designated R-3327-HI. In addition, a rapidly growing hormone-insensitive anaplastic tumor has been developed, R-3327-AT. These three tumor lines have been characterized, and their histological and biochemical profiles are compared.

Adenocarcinoma↗
PubMed1977

Acquisition of increased hormone sensitivity during in vitro adipocyte development.

Murine 3T3-L1 fibroblasts enter a differentiation program subsequent to prolonged maintenance in the confluent state and develop into adipocytes. The hormone sensitivity of adenylate cyclase and the physiological responsiveness to insulin were compared in 3T3-L1 preadipocytes and adipocytes. The following observations, comprising several distinct categories of hormone responsiveness, were made. (a) (2.5 micronM) isoproterenol stimulated adenylate cyclase 15-fold in adipocyte homogenates, but only 2.5-fold in preadipocyte preparations, suggesting a considerable magnification in beta-adrenergic responsiveness during development. (b) A totally new control element, adrenocorticotropic hormone responsiveness, was incorporated into the adenylate cyclase system of the adipocytes. (c) Sensitivity to prostaglandin E1 was observed in both preadipocytes and adipocytes, but no change in responsiveness could be detected in the differentiated cells. (d) Glucagon-sensitive adenylate cyclase could not be detected in either preadipocytes or adipocytes. (e) Both preadipocytes and adipocytes possess considerable insulin binding activity, but near physiological levels of insulin stimulate the conversion of glucose to CO2 and lipid only in the differentiated cells.

Adenylyl Cyclases↗
PubMed1972

Loss of a parathyroid hormone-sensitive component of phosphate transport in X-linked hypophosphatemia.

Mutant hemizygotes with X-linked hypophosphatemia lack a parathyroid hormone-sensitive component of inorganic phosphate transport in kidney; female heterozygotes retain a variable proportion of this type of transport. The residual mechanism for reabsorption in affected males allows inorganic phosphate efflux from the kidney to urine so that net "secretion" is sometimes observed; the latter is directly proportional to the serum concentration of inorganic phosphate. Calcium acts on the kidney tubule to enhance net reabsorption by this component of inorganic phosphate transport.

Adolescent↗
PubMed1989

Characterization of hormone-sensitive adenylate cyclase in rabbit gallbladder mucosa.

1. We have developed a plasma membrane preparation from the mucosal epithelium of rabbit gallbladder and have characterized the hormonal sensitivity of adenylate cyclase in this preparation. 2. Basal activity is low and is stimulated by GTP and GppNHp. Hormonal stimulation is largely dependent on exogenous guanine nucleotide. 3. Several prostaglandins (E1 approximately E2 greater than A1 greater than B1), vasoactive intestinal peptide and the beta-adrenergic agonist, isoproterenol, stimulate mucosal adenylate cyclase activity; a variety of peptides and neurotransmitters (secretin, cholecystokinin, arg-vasopressin, oxytocin, histamine, dopamine and serotonin) are without effect. 4. The data support the hypothesis that the inhibitory effect of prostaglandins, vasoactive intestinal peptide, and isoproterenol on gallbladder fluid absorption in certain species may be mediated by cyclic AMP. 5. The membrane preparation should be useful in further characterizing hormone receptor-transducer interactions of the gallbladder mucosal epithelium.

Adenylyl Cyclases↗
PubMed2001

Variation in the promoter of the human hormone sensitive lipase gene shows gender specific effects on insulin and lipid levels: results from the Ely study.

We previously identified a hormone sensitive lipase (HSL) promoter variant, -60C>G, which in vitro exhibits 40% reduced promoter activity. In this study we examined the effect of the -60C>G on glycemic and lipid measures in the population based Ely study of metabolic function and insulin resistance in 218 middle-aged men and 276 middle-aged women. Adipose tissue HSL is the rate-limiting step in triglyceride lipolysis, generating free fatty acids for energy utilization. HSL is also expressed in pancreatic beta-cells where its activity therefore may affect insulin secretion. In the women, carriers of the HSL -60G allele had significantly lower fasting insulin levels (P=0.0005) and a lower total area under the curve for insulin during the oral glucose tolerance test (P=0.005). There was no demonstrable association in men with these measures of insulin sensitivity but carriers of the -60G allele had significantly lower fasting non-esterified fatty acid (NEFA) levels (P=0.025) and higher low density lipoprotein cholesterol levels (P=0.02) than men who were non-carriers. This study provides additional evidence for a role for HSL in the development of insulin resistance, from which carriers of the -60G allele, associated here with markers of insulin sensitivity in women, and with lower NEFA levels in men, might be protected.

Diabetes Mellitus, Type 2↗
PubMed2003

Pyrrolopyrazinedione-based inhibitors of human hormone-sensitive lipase.

The regulation of lipid metabolism and it's effect on glucose control and diabetes has received intense interest. Hormone-sensitive lipase (HSL) is a vital enzyme in lipid metabolism. A series of novel pyrrolopyrazinediones has been discovered that demonstrate submicromolar activity both in the enzyme assay and in a (14)C-emulsion assay employing cholesteryl oleate as a substrate as a secondary measure of HSL activity. These compounds represent novel inhibitors of the human HSL enzyme.

Animals↗
PubMed1999

Testis expression of hormone-sensitive lipase is conferred by a specific promoter that contains four regions binding testicular nuclear proteins.

The testicular isoform of hormone-sensitive lipase (HSLtes) is encoded by a testis-specific exon and 9 exons common to the testis and adipocyte isoforms. In mouse, HSLtes mRNA appeared during spermiogenesis in round spermatids. Two constructs containing 1.4 and 0.5 kilobase pairs (kb) of the human HSLtes gene 5'-flanking region cloned upstream of the chloramphenicol acetyltransferase gene were microinjected into mouse oocytes. Analyses of enzyme activity in male and female transgenic mice showed that 0.5 kb of the HSLtes promoter was sufficient to direct expression only in testis. Cell transfection experiments showed that CREMtau, a testis-specific transcriptional activator, does not transactivate the HSLtes promoter. Using gel retardation assays, four testis-specific binding regions (TSBR) were identified using testis and liver nuclear extracts. The testis-specific protein binding on TSBR4 was selectively competed by a probe containing a SRY/Sox protein DNA recognition site. Sox5 and Sox6 which are expressed in post-meiotic germ cells bound TSBR4. Mutation of the AACAAAG motif in TSBR4 abolished the binding. Moreover, binding of the high mobility group domain of Sox5 induced a bend within TSBR4. Together, our results showed that 0.5 kb of the human HSLtes promoter bind Sox proteins and contain cis-acting elements essential for the testis specificity of HSL.

Animals↗
PubMed2001

The expression of hormone-sensitive lipase in clonal beta-cells and rat islets is induced by long-term exposure to high glucose.

Hormone-sensitive lipase (HSL) is expressed and enzymatically active in beta-cells and has been proposed to be involved in the generation of the lipid-derived signal that seems to be necessary for glucose-stimulated insulin secretion. In this study, we investigated whether the expression of HSL in INS-1 cells and in rat islets is affected by exposure to high glucose concentrations. Incubation of INS-1 cells in 25 mmol/l glucose for 16 and 32 h induced HSL protein expression twofold, whereas no effect was observed after 4 and 8 h of incubation. The HSL activity, defined as the diglyceride lipase activity inhibited by anti-rat HSL antibodies, constituted approximately 25% of total diglyceride lipase activity and was induced to a similar extent as HSL protein levels. The glucose effect at 16 h on HSL protein expression level was confirmed in freshly isolated rat islets. Exposure of INS-1 cells to different glucose concentrations for 16 h showed that the inductive effect on HSL protein levels was maximum at 20 mmol/l glucose (2- to 2.5-fold). Northern blot analysis demonstrated a more than threefold elevation of HSL mRNA levels. The induction was blocked by actinomycin D, and the half-life of the transcript seemed to be unchanged by high glucose, suggesting a transcriptional nature of the glucose effect on HSL gene expression. The nonmetabolizable glucose analog 2-deoxyglucose, which has no mitogenic effect, induced HSL approximately 1.3-fold, whereas mannose was similar to glucose, stimulating HSL expression 1.7- to 2-fold. The results suggest that HSL is involved in the beta-cell responses to hyperglycemia and also in generating the lipid signal that is needed in stimulus-secretion coupling.

Animals↗
PubMed2003

Effects of plasma adrenaline on hormone-sensitive lipase at rest and during moderate exercise in human skeletal muscle.

We investigated the effect of increased plasma adrenaline on hormone-sensitive lipase (HSL) activity and extracellular regulated kinase (ERK) 1/2 phosphorylation during exercise. Seven untrained men rested for 20 min and exercised for 10 min at 60 % peak pulmonary oxygen uptake on three occasions: with adrenaline infusion throughout rest and exercise (ADR), with no adrenaline infusion (CON) and with adrenaline infusion commencing after 3 min of exercise (EX+ADR). Muscle samples were obtained at rest before (Pre, -20 min) and after (0 min) infusion, and at 3 and 10 min of cycling. Exogenous adrenaline infusion increased (P < 0.05) plasma adrenaline at rest during ADR, which resulted in greater HSL activity (Pre, 2.14 +/- 0.10 mmol min-1 (kg dry matter (dm))-1; 0 min, 2.74 +/- 0.20 mmol min-1 (kg dm)-1). Subsequent exercise had no effect on HSL activity. During exercise in CON, HSL activity was increased (P < 0.05) above rest at 3 min but was not increased further by 10 min. The infusion of exogenous adrenaline at 3 min of exercise in EX+ADR resulted in a marked elevation in plasma adrenaline levels (3 min, 0.57 +/- 0.12 nM; 10 min, 10.08 +/- 0.84 nM) and increased HSL activity by 25 %. HSL activity at 10 min was greater (P < 0.05) in EX+ADR compared with CON. There were no changes between trials in the plasma concentrations of insulin and free fatty acids (FFA) and the muscle contents of free AMP, all putative regulators of HSL activity. ERK1/2 phosphorylation increased at 3 min in CON and EX+ADR. Because HSL activity did not increase during exercise when adrenaline was infused prior to exercise (ADR) and because HSL activity increased when adrenaline was infused during exercise (EX+ADR), we conclude that (1) high adrenaline levels can stimulate HSL activity regardless of the metabolic milieu and (2) large increases in adrenaline during exercise, independent of changes in other putative regulators, are able to further stimulate the contraction-induced increase in HSL activity. The results also demonstrate that increased ERK 1/2 phosphorylation coincides with elevated HSL activity, indicating that ERK 1/2 may mediate the contraction-induced increase in HSL activity early in exercise.

Adult↗
PubMed2000

Free fatty acids are involved in the inverse relationship between hormone-sensitive lipase (HSL) activity and expression in adipose tissue after high-fat feeding or beta3-adrenergic stimulation.

OBJECTIVE: The hormone-sensitive lipase (HSL) is the rate-limiting enzyme in adipose tissue lipolysis. The aim of this experimental trial was to study the effects of a beta3-adrenergic agonist (Trecadrine) on plasma fatty acids, adipocyte HSL activity, and gene expression in control and cafeteria-induced obese animals. RESEARCH METHODS AND PROCEDURES: Control and cafeteria-fed rats were treated with a placebo or Trecadrine during 35 days. Plasma fatty acids were measured by an enzymatic method, whereas HSL activity was assessed by using labeled triolein as substrate. Finally, HSL gene expression from white adipose tissue (WAT) was determined using a reverse transcription-polymerase chain reaction method. RESULTS: Trecadrine administration reduced plasma fatty acids and HSL mRNA levels in abdominal WAT, whereas HSL activity was significantly higher in the Trecadrine-treated obese rats than in the obese nontreated rats. Also, abdominal WAT HSL activity significantly increased, whereas WAT HSL gene expression fell in control rats treated with beta3-adrenergic agonist as compared with control untreated animals. DISCUSSION: In situations of fat accumulation (high-fat feeding) or lipid mobilization (beta3-adrenergic stimulation), changes in HSL activity and HSL gene expression seem to follow a trend related to plasma fatty acids levels, as indicated by the positive correlation (r = 0.39, p < 0.05) between HSL mRNA levels and plasma fatty acids, and the negative correlation (r = -0.38, p < 0.05) between plasma fatty acids and HSL activity. Furthermore, a highly negative correlation (r = -0.59, p < 0.001) between HSL activity and HSL mRNA expression was found, in which plasma-free fatty acids are apparently involved.

Adipose Tissue↗