Expression of nitric oxide synthases in subcutaneous adipose tissue of nonobese and obese humans

Abstract

Studies have shown evidence of production of nitric oxide (NO) in adipose tissue, as well as inhibition of lipolysis by NO. We have analyzed nitric oxide synthase (NOS) expression in subcutaneous adipose tissue from 13 nonobese and 18 obese male subjects. Using a competitive reverse transcription polymerase chain reaction method, endothelial (eNOS) and inducible (iNOS), but not neuronal (nNOS), nitric oxide synthase mRNA expression was detected in isolated fat cells and pieces of adipose tissue. Tissue mRNA levels for eNOS were 3,814 ± 825 and 5,956 ± 476 amol/mg RNA (P = 0.043), and for iNOS 306 ± 38 and 332 ± 48 amol/mg RNA, for nonobese and obese individuals, respectively. Western blotting revealed similar eNOS protein levels in isolated fat cells and adipose tissue pieces. Protein levels for eNOS in nonobese and obese individuals, respectively, were (in optical density [OD] units per mm2 per 100 μg of total protein) 0.11 ± 0.08 and 2.80 ± 1.30 (P = 0.043). iNOS protein was detectable, but not measurable, at low levels in a subset of obese patients (3 of 10). iNOS protein levels could not be detected in nonobese individuals. Hormone-sensitive lipase (HSL), the key regulating enzyme in lipolysis, is reduced in obesity. The expression of HSL protein in subcutaneous adipose tissue was studied in the same subset of patients; in agreement with previous results, HSL levels were reduced in obese subjects: 4.64 ± 1.10 and 1.27 ± 0.35 (P = 0.012) in nonobese and obese subjects, respectively. In conclusion, this study shows that eNOS and iNOS, but not nNOS, are present in human subcutaneous adipose tissue. Gene expression and protein levels of eNOS are increased, whereas HSL protein levels are decreased in obesity. It is speculated that increased NO production, preferably by eNOS, and decreased HSL levels may cause decreased subcutaneous adipose tissue lipolysis in obesity. —Elizalde, M., M. Rydén, V. van Harmelen, P. Eneroth, H. Gyllenhammar, C. Holm, S. Ramel, A. Ölund, P. Arner, and K. Andersson. Expression of nitric oxide synthases in subcutaneous adipose tissue of nonobese and obese humans. J. Lipid Res. 2000. 41: 1244–1251. Studies have shown evidence of production of nitric oxide (NO) in adipose tissue, as well as inhibition of lipolysis by NO. We have analyzed nitric oxide synthase (NOS) expression in subcutaneous adipose tissue from 13 nonobese and 18 obese male subjects. Using a competitive reverse transcription polymerase chain reaction method, endothelial (eNOS) and inducible (iNOS), but not neuronal (nNOS), nitric oxide synthase mRNA expression was detected in isolated fat cells and pieces of adipose tissue. Tissue mRNA levels for eNOS were 3,814 ± 825 and 5,956 ± 476 amol/mg RNA (P = 0.043), and for iNOS 306 ± 38 and 332 ± 48 amol/mg RNA, for nonobese and obese individuals, respectively. Western blotting revealed similar eNOS protein levels in isolated fat cells and adipose tissue pieces. Protein levels for eNOS in nonobese and obese individuals, respectively, were (in optical density [OD] units per mm2 per 100 μg of total protein) 0.11 ± 0.08 and 2.80 ± 1.30 (P = 0.043). iNOS protein was detectable, but not measurable, at low levels in a subset of obese patients (3 of 10). iNOS protein levels could not be detected in nonobese individuals. Hormone-sensitive lipase (HSL), the key regulating enzyme in lipolysis, is reduced in obesity. The expression of HSL protein in subcutaneous adipose tissue was studied in the same subset of patients; in agreement with previous results, HSL levels were reduced in obese subjects: 4.64 ± 1.10 and 1.27 ± 0.35 (P = 0.012) in nonobese and obese subjects, respectively. In conclusion, this study shows that eNOS and iNOS, but not nNOS, are present in human subcutaneous adipose tissue. Gene expression and protein levels of eNOS are increased, whereas HSL protein levels are decreased in obesity. It is speculated that increased NO production, preferably by eNOS, and decreased HSL levels may cause decreased subcutaneous adipose tissue lipolysis in obesity. —Elizalde, M., M. Rydén, V. van Harmelen, P. Eneroth, H. Gyllenhammar, C. Holm, S. Ramel, A. Ölund, P. Arner, and K. Andersson. Expression of nitric oxide synthases in subcutaneous adipose tissue of nonobese and obese humans. J. Lipid Res. 2000. 41: 1244–1251. Nitric oxide (NO) is produced in many different cells and is involved in the regulation of such physiologic events as inflammation, vascular tone, and metabolism (see refs. 1Christopherson K.S. Bredt D.S. Perspectives series: nitric oxide and nitric oxide synthases.J. Clin. Invest. 1997; 100: 2424-2429Google Scholar and 2Michel T. Feron O. Nitric oxide synthases: which, how, and why?.J. Clin. Invest. 1997; 100: 2146-2152Google Scholar). Depending on cell type, NO is formed in an enzymatic reaction catalyzed by one of the three isoforms of NO synthase (NOS) (see ref. 2Michel T. Feron O. Nitric oxide synthases: which, how, and why?.J. Clin. Invest. 1997; 100: 2146-2152Google Scholar). Neuronal NOS (nNOS) and endothelial NOS (eNOS) are constitutive, and produce small amounts of NO after stimuli that raise intracellular Ca2+ concentrations. The third isoform, inducible NOS (iNOS), is expressed after induction by agents such as cytokines and bacterial lipopolysaccharide. eNOS and iNOS have been shown to be present in white adipose tissue of the rat (3Ribiere C. Jaubert A.M. Gaudiot N. Sabourault D. Marcus M.L. Boucher J.L. Denis-Henriot D. Giudicelli Y. White adipose tissue nitric oxide synthase: a potential source for NO production.Biochem. Biophys. Res. Commun. 1996; 222: 706-712Google Scholar), suggesting that this tissue may be a potential source of NO production. We have demonstrated the presence of NOS activity and iNOS protein also in human subcutaneous adipose tissue (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). Moreover, we showed that inhibition of NOS resulted in increased lipolysis in this tissue. Conversely, addition of NO caused an inhibition of lipolysis in intact adipose tissue in vivo, as well as in isolated fat cells in vitro in humans. Together, these results suggest an important role for NO in the regulation of lipolysis in humans (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). It is still unclear which NOS isoforms are present in human adipose tissue. Work by Ribiere et al. (3Ribiere C. Jaubert A.M. Gaudiot N. Sabourault D. Marcus M.L. Boucher J.L. Denis-Henriot D. Giudicelli Y. White adipose tissue nitric oxide synthase: a potential source for NO production.Biochem. Biophys. Res. Commun. 1996; 222: 706-712Google Scholar), suggests that it is the stimulation of iNOS that substantially contributes to NO production in rodent adipose tissue. It is known from several studies that catecholamine-stimulated lipolysis is reduced in obesity (5Arner P. Regulation of lipolysis in fat cells.Diabetes Rev. 1996; 4: 450-463Google Scholar). However, the exact mechanisms underlying this phenomenon remain unknown, although a number of possible causes have been suggested. Our group demonstrated that expression of hormone-sensitive lipase (HSL), the rate-limiting enzyme in adipocyte lipolysis (6Langin D. Holm C. Lafontan M. Adipocyte hormone-sensitive lipase: a major regulator of lipid metabolism.Proc. Nutr. Soc. 1996; 55: 93-109Google Scholar), is reduced in adipocytes of obese subjects (7Large V. Reynisdottir S. Langin D. Fredby K. Klannemark M. Holm C. Arner P. Decreased expression and function of adipocyte hormone-sensitive lipase in subcutaneous fat cells of obese subjects.J. Lipid Res. 1999; 40: 2059-2066Google Scholar). Molecular mechanisms governing this finding remain to be resolved. Studies of rat isolated fat cells have shown that NO-mediated regulation of lipolysis is complex (8Gaudiot N. Jaubert A-M. Charbonnier E. Sabourault D. Lacasa D. Giudicelli Y. Ribière C. Modulation of white adipose tissue lipolysis by nitric oxide.J. Biol. Chem. 1998; 273: 13475-13481Google Scholar). Thus, the nitric oxide donor 1-propamine 3- (2-hydroxy-2-nitroso-1-propylhydrazine) (PAPA-NONOate) and NO gas have no effect on basal lipolysis but nitrosothiols such as S-nitroso-N-acetyl-penicillamine (SNAP) and S-nitrosglutathione stimulate basal lipolysis in rat adipose tissue. However, SNAP inhibits catecholamine-stimulated lipolysis, possibly by reducing the production of cyclic AMP (cAMP), and PAPA-NONOate and NO gas reduce lipolysis induced by catecholamines as well as other agents without altering cAMP production. Beside the inhibition of cAMP-dependent HSL activation it was suggested in the same study that NO can inactivate HSL by a direct mechanism that is not fully understood (8Gaudiot N. Jaubert A-M. Charbonnier E. Sabourault D. Lacasa D. Giudicelli Y. Ribière C. Modulation of white adipose tissue lipolysis by nitric oxide.J. Biol. Chem. 1998; 273: 13475-13481Google Scholar). It is thus feasible that NO exerts its antilipolytic effect by downregulating lipolytic pathways. A previous study showed an inhibitory mechanism of NO on both basal and stimulated lipolysis in human adipose tissue (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar), indicating important species differences in the action of NO on lipolysis in rats versus humans. In the earlier human study only the presence of iNOS protein was investigated. Here, we investigated more carefully which NOS isoforms are present in human subcutaneous adipose tissue. We also determined whether NOS gene expression and protein levels are changed in the obese state. In view of the previously demonstrated reduction in HSL expression in obese individuals, we also studied whether there was a parallel change in HSL and NOS in obesity. All subjects were male caucasians born in Sweden. The control group (ages 34–68 years) consisted of 13 nonobese men, and the study group (ages 24–57 years) consisted of 18 obese men. These groups took part in the studies of mRNA expression for eNOS, iNOS, and as well as in of protein levels for eNOS and The control subjects were for The obese subjects were reduction with All subjects were subjects were also for such as of NOS gene expression and protein levels These for such as The study was by the of All subjects to in the The subjects and subcutaneous adipose tissue were from the after the of the was the tissue pieces were was as previously V. Reynisdottir S. van V. Arner P. in human fat cells and J. 1997; Scholar). cells were isolated from of the subjects to the of M. of isolated fat Biol. Chem. Scholar). tissue from human was by S. of All tissue pieces were in and at for mRNA The were from the eNOS and iNOS by et al. S. A. M. Gene and of the human endothelial nitric oxide synthase Biophys. Res. Commun. and et al. S. P. Molecular and of the human inducible nitric oxide synthase gene Biophys. Res. Commun. 1996; Scholar), respectively. The of the were for eNOS and for The an The for in human was and for as a was as by et al. M. and of a human RNA 4: and et al. H. Y. A.M. of the human neuronal nitric oxide synthase gene Biol. Chem. Scholar), respectively. The were and the reverse were The in S. A. M. Gene and of the human endothelial nitric oxide synthase Biophys. Res. Commun. in S. A. M. Gene and of the human endothelial nitric oxide synthase Biophys. Res. Commun. in S. P. Molecular and of the human inducible nitric oxide synthase gene Biophys. Res. Commun. 1996; in S. P. Molecular and of the human inducible nitric oxide synthase gene Biophys. Res. Commun. 1996; from human in M. and of a human RNA 4: in M. and of a human RNA 4: in H. Y. A.M. of the human neuronal nitric oxide synthase gene Biol. Chem. in H. Y. A.M. of the human neuronal nitric oxide synthase gene Biol. Chem. with the same as the for eNOS and for iNOS a in the of the was The for eNOS were at type, The for iNOS were at type, These were as in a polymerase chain reaction The was with the for eNOS and iNOS, respectively. The RNA polymerase was to the in a of and in the the RNA polymerase addition was as in an in vitro transcription reaction to the RNA The reaction consisted of of of and 100 of RNA polymerase and was at The reaction was by to The was by it for with of and the RNA was isolated with the from and as in the reverse the an was that with the RNA, but that a as well as an the a was with the as which a part of the gene by J. The were The a a the for and a The reverse a an the for and a The of these were as and for are The was with and and was a by J. and The was with to of with were with the and on and A was and an of this was with The was in vitro and the was The RNA was on a and the was determined The of the was RNA was from subcutaneous fat tissue cell the The of the RNA was by in a The RNA was In the eNOS competitive of total RNA was reverse and with amounts of 100 and in the iNOS competitive of total RNA was reverse with and of and in the competitive of total RNA was reverse with and of RNA, and were at for The reaction was and for at for at and for at The reaction consisted of of reverse of and the at The reverse transcription was at The were in the The were by iNOS the reaction of the of and of and in a of The same were for the eNOS the reaction of of the of and of The consisted of at of of at at the and at and a of at The were as eNOS, iNOS and The was The were at and on with to the of the iNOS and The of was to et al. J. C. J. Elizalde M. K. of mRNA in a cell a competitive reverse transcription polymerase chain reaction 1998; Scholar). The were to The were to for and for of the The were with on were and The of the for the were as to the The were with enzyme and with The was by a of the The from the of total versus of the of the of RNA were in the part of the to for of the of the and the with were in the A is shown in The were on a and with a The optical density of on the was determined with The was as a function of and the of RNA was as tissue from subcutaneous tissue of obese and nonobese subjects were in and at subjects, isolated fat cells were to the of M. of isolated fat Biol. Chem. the of protein from adipose tissue from to were and in protein with and with a The was at for and the and All were at to the of The protein in was determined with a of from and μg of total protein was on and by control for differences in and from obese and nonobese subjects were on the same and to the same were in and with eNOS, iNOS both from and HSL by were in as by the as to to were from and iNOS, were detected by with a of and to were and the optical density of analyzed with the and expressed as units per mm2 per 100 μg of total The were and reverse and RNA enzyme and and RNA polymerase addition RNA was with the are as ± differences were analyzed by was as a mRNA for eNOS and iNOS were detected in adipose tissue, as well as in isolated fat cells were for eNOS and iNOS The of the was by In subjects, an mRNA expression was for eNOS, as with iNOS mRNA expression was for eNOS and iNOS in adipose tissue and isolated fat indicating that at a part of eNOS and iNOS mRNA from the adipocytes we a of mRNA levels from it was possible to both eNOS and iNOS from isolated fat we were to the gene expression in isolated fat cells a was a finding for which at present we have no and ± ± ± ± amol/mg ± ± amol/mg ± ± amol/mg amol/mg ± ± μg total ± ± μg total μg total ± ± ± were tissue mRNA was in 13 nonobese and 18 obese subjects. tissue protein levels were in nonobese and obese individuals. not not in a The ± were tissue mRNA was in 13 nonobese and 18 obese subjects. tissue protein levels were in nonobese and obese individuals. not not a neuronal NOS could be from human tissue, mRNA could not be in adipose tissue. We were to a with a from but showed that this no with Studies on intact subcutaneous adipose tissue revealed that eNOS mRNA levels were in the obese individuals. shows that expression levels were increased by (P = as with nonobese subjects. In although we could iNOS, we no in levels of this mRNA species the control for in gene the gene the protein was in the expression of this gene could be indicating that the in eNOS mRNA expression was Western showed similar levels of eNOS protein in both adipose tissue and isolated fat cells suggesting that eNOS protein is to a from the adipocytes and not from endothelial cells present in the of adipose tissue. finding to protein on adipose tissue the nonobese and obese in the same Western it was only possible to a of for mRNA was also eNOS protein was in and by In agreement with the mRNA it was that eNOS protein levels were increased in the obese subjects by as as (P = The of versus obese is were on the same Moreover, the same of protein as for eNOS, iNOS protein was not detected in nonobese and obese not finding was in to previous the presence of iNOS protein in subcutaneous tissue of obese subjects (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar), and we studies and μg of protein in of obese low levels of iNOS protein could be Thus, in agreement with previous iNOS protein is present although at low levels in human adipose of eNOS, iNOS, and HSL protein in adipose tissue of nonobese and obese subjects. of protein from nonobese and obese subjects was on the same by and eNOS protein was detected by Western that eNOS levels are in the obese A eNOS control from human endothelial cells was to of from the same subjects as in was on the same by and iNOS protein was detected by Western iNOS protein was not in nonobese and was in only of the obese individuals. of the increased of only 18 could be on the same The nonobese and not iNOS protein A iNOS control from was to The shown in was and with an that HSL levels were in the obese NOS protein levels to levels of regulating lipolysis, the for NOS were and with an HSL protein levels were decreased by (P = 0.012) in the obese and a finding in with previous results from (7Large V. Reynisdottir S. Langin D. Fredby K. Klannemark M. Holm C. Arner P. Decreased expression and function of adipocyte hormone-sensitive lipase in subcutaneous fat cells of obese subjects.J. Lipid Res. 1999; 40: 2059-2066Google Scholar). was eNOS and HSL protein levels = although eNOS gene expression to be to HSL protein levels = The presence of NOS in adipose tissue been demonstrated previously (3Ribiere C. Jaubert A.M. Gaudiot N. Sabourault D. Marcus M.L. Boucher J.L. Denis-Henriot D. Giudicelli Y. White adipose tissue nitric oxide synthase: a potential source for NO production.Biochem. Biophys. Res. Commun. 1996; 222: 706-712Google K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). In the present study we for the the of obesity on NOS adipose tissue. is of in the role of NO in lipolysis regulation (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google N. Jaubert A-M. Charbonnier E. Sabourault D. Lacasa D. Giudicelli Y. Ribière C. Modulation of white adipose tissue lipolysis by nitric oxide.J. Biol. Chem. 1998; 273: 13475-13481Google the of low lipolysis in obesity (5Arner P. Regulation of lipolysis in fat cells.Diabetes Rev. 1996; 4: 450-463Google Scholar). we present a for of eNOS and iNOS a competitive is on one similar to that by et al. J. C. J. Elizalde M. K. of mRNA in a cell a competitive reverse transcription polymerase chain reaction 1998; Scholar). The is by the to the RNA, for a of is reverse and with the same of both are by and the after and are by with in and are detected and by enzyme RNA, such as a gene P. O. M. D. A. A for mRNA from a Scholar), RNA S. reverse polymerase chain reaction of mRNA with the RNA as a 1996; is as may be and with different there may be as to whether such are also by studied J. C. J. Elizalde M. K. of mRNA in a cell a competitive reverse transcription polymerase chain reaction 1998; Scholar). The of an from the same gene as the a major of the in the of the and the and are reduced to a A. P. S. E. V. an K. polymerase chain reaction without an Scholar). We have this to for the gene expression for endothelial and inducible NOS mRNA in human fat tissue. We were to mRNA for both eNOS and iNOS in adipose tissue as well as in isolated fat The of eNOS is in the endothelial Our results, similar expression levels in adipose tissue and isolated fat suggest that eNOS mRNA in human subcutaneous fat is to a from the adipocytes and not from endothelial cells the We also demonstrated eNOS protein in human adipose tissue and in isolated cells by of Western The results also suggest that eNOS protein from the fat cells of human adipose tissue. The expression of iNOS mRNA was that for eNOS finding is in with previous on low levels of iNOS protein in rodent adipose tissue (3Ribiere C. Jaubert A.M. Gaudiot N. Sabourault D. Marcus M.L. Boucher J.L. Denis-Henriot D. Giudicelli Y. White adipose tissue nitric oxide synthase: a potential source for NO production.Biochem. Biophys. Res. Commun. 1996; 222: 706-712Google Scholar). in previous we could low levels of iNOS protein in obese subjects (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). In the present the same we could not iNOS protein in adipose tissue of nonobese in a subset of the obese subjects (3 of levels of iNOS protein could be Thus, in to in the eNOS to be the expressed NOS in human adipose tissue in both the nonobese and obese both at the mRNA and protein In agreement with results from rat fat tissue, we that mRNA was not expressed in human adipose tissue. Using and Western we that adipose tissue pieces from obese showed increased eNOS gene expression and protein levels as with tissue from nonobese subjects. However, it was not possible to gene expression in isolated fat The for this is at present The in eNOS gene expression and protein levels in the obese subjects to be a change mRNA levels for iNOS the were and also that were for HSL protein of the NOS been shown to lipolysis in subjects, indicating a role for NO in regulation of lipolysis in humans (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). In reduced catecholamine-stimulated lipolysis is shown (5Arner P. Regulation of lipolysis in fat cells.Diabetes Rev. 1996; 4: 450-463Google Langin H. Reynisdottir S. M. Arner P. Adipocyte lipolysis in subjects with obesity 1996; Scholar), the basal of lipolysis is increased (5Arner P. Regulation of lipolysis in fat cells.Diabetes Rev. 1996; 4: 450-463Google Scholar). In previous we in subjects, that NO gas and NO from can reduce lipolysis in isolated fat cells (4Andersson K. Gaudiot N. Ribiere C. Elizalde M. Giudicelli Y. Arner P. A nitric oxide-mediated mechanism regulates lipolysis in human adipose tissue in vivo.Br. J. Pharmacol. 1999; 126: 1639-1645Google Scholar). In view of these results, the that eNOS expression is increased in obese suggest that eNOS is involved in regulating catecholamine-stimulated However, studies are to the exact role of NO in regulating lipolysis in the obese and nonobese state. In this it also be of to NO production and NOS adipose tissue in the was for such The of NO on lipolysis to study the possible to which is suggested to be the rate-limiting enzyme in adipocyte lipolysis (6Langin D. Holm C. Lafontan M. Adipocyte hormone-sensitive lipase: a major regulator of lipid metabolism.Proc. Nutr. Soc. 1996; 55: 93-109Google Scholar). It been shown that HSL protein levels the lipolytic of human fat cells V. Arner P. Reynisdottir S. J. van V. Holm C. Langin D. Hormone-sensitive lipase expression and activity in to lipolysis in human fat Lipid Res. 1998; Scholar). A decreased expression and function of HSL in adipose tissue from obese subjects was also shown and suggested to cause the decreased lipolytic of fat cells (7Large V. Reynisdottir S. Langin D. Fredby K. Klannemark M. Holm C. Arner P. Decreased expression and function of adipocyte hormone-sensitive lipase in subcutaneous fat cells of obese subjects.J. Lipid Res. 1999; 40: 2059-2066Google Scholar). The present study in a different of individuals, that obese reduced HSL protein levels in subcutaneous adipose tissue. In the present we analyzed for a possible protein levels of eNOS and HSL in adipose tissue of nonobese and obese individuals. eNOS and HSL levels were determined on the same with the same differences in protein levels could be the for eNOS and HSL protein levels that a effect of obesity on protein levels was eNOS and HSL protein levels to an but not indicating that these were of eNOS HSL many NOS activation and a possible change in HSL and thus a eNOS and HSL protein levels may not as to a possible these are to the HSL and eNOS expression a direct NO and HSL that may lipolysis in obesity. In conclusion, the present study the presence of eNOS and iNOS, but not nNOS, gene expression and of eNOS and iNOS protein levels in both human subcutaneous adipose tissue and isolated fat was by increased mRNA gene expression of eNOS, but not iNOS, as well as by increased eNOS protein the increased eNOS protein levels were with reduced HSL protein levels in obese individuals. The in both HSL and eNOS expression may to the reduced of lipolysis in obesity. study was by from the the the and the the of the and the of and The of and is