張勇 李之俊
1 上海體育學院運動科學學院(上海 200438)
2 浙江師范大學體育與健康科學學院 3 上海體育科學研究所
儲存在脂肪細胞中的脂肪被脂肪酶逐步水解為游離脂肪酸及甘油并釋放入血以供其它組織氧化利用的過程稱為脂肪動員。脂肪的動員和氧化利用障礙不僅影響機體的氧化供能,還可導致肥胖及與之相關的胰島素抵抗、血脂紊亂、高血壓等代謝綜合征的發(fā)生,而運動不僅對脂肪的動員和氧化利用具有直接作用,也可通過神經(jīng)、激素和血循環(huán)對機體的脂肪動員和氧化利用發(fā)揮調節(jié)作用,長期運動也可能會對基礎狀態(tài)和應激狀態(tài)下機體調節(jié)脂代謝的能力具有改善作用。因此,研究運動與脂肪動員和氧化利用的規(guī)律及其相關調節(jié)機制具有重要意義?,F(xiàn)從參與脂肪動員的脂肪酶及相關蛋白、脂肪動員的激素調節(jié)機制、運動與脂肪動員及氧化利用三個方面對脂肪組織動員和氧化利用及其相關調節(jié)機制加以綜述,以期有助于今后的研究和實踐。
一般認為脂肪甘油三酯酶(adipose triglyceride lipase,ATGL),激素敏感性脂肪酶(hormonesensitive lipase,HSL)和 甘油一酯酶(monoglyceride lipase,MGL)對脂肪組織具有脂解作用,與它們發(fā)揮脂解作用相關的主要蛋白有脂滴包被蛋白(Perilipin)、比較基因序列58(Comparative Gene Identi fication 58,CGI-58)、脂肪酸結合蛋白 4(fatty acid binding protein-4,F(xiàn)ABP4)等。
perilipin是覆蓋在脂肪細胞脂滴上的蛋白,perilipin A和perilipin B是最早被證實的脂滴蛋白,在成熟脂肪細胞主要是perilipin A[1]。Perilipin可調節(jié)各種細胞的脂肪儲備和利用[2,3]。在基礎狀態(tài),perilipin可在脂滴表面形成一個屏障,阻止脂肪酶接觸到脂滴內的甘油三酯,抑制脂肪分解。脂解激素刺激后 ,perilipin A是最主要的磷酸化蛋白,它通過環(huán)磷酸腺苷(cAMP)及蛋白激酶A(PKA)途徑磷酸化,使脂滴結構重組,甘油三酯與脂肪酶結合,甘油三酯分解[1,4]。另外,PKA調節(jié)的perilipin磷酸化還可導致CGI-58釋放,而CGI-58可與ATGL相互作用促使其充分激活[5]。因此,perilipin表達和磷酸化是正常脂解調節(jié)的重要條件。
2002年,Haemmerle等[6]發(fā)現(xiàn),在HSL基因敲除情況下,甘油三酯脂解下降僅為40%,而甘油二酯大量堆積,推測可能存在另一種酶對甘油三酯分解具有作用。隨后該課題組在2004年發(fā)現(xiàn)了這個后來被命名為ATGL的脂肪酶(一個在脂肪組織高度表達的54 kDa的486氨基酸蛋白)[7]。隨后的一系列研究不僅證實ATGL在基礎狀態(tài)和應激狀態(tài)具有促進脂解作用[8-12],而且發(fā)現(xiàn)與HSL缺乏動物相比,ATGL缺乏動物更易肥胖,ATGL缺乏可導致來自白色脂肪組織的脂肪酸減少75%以上,甘油三酯在組織和器官快速積累,導致代謝異常[9]。結合已有研究后認為,ATGL對甘油三酯的特異性比甘油二酯高,它分解甘油三酯的能力比HSL強,而HSL在甘油二酯分解為甘油一酯和脂肪酸過程中具有重要作用[6],最后在甘油一酯酶作用下完全分解為甘油和脂肪酸。從這個理論來看,ATGL不僅在甘油三酯分解過程中起主要作用,而且甘油三酯分解產(chǎn)生的甘油二酯是HSL促脂解的主要底物[11],無論在基礎條件下還是在刺激條件下,ATGL活化對脂肪組織脂解具有重要作用,HSL是甘油三酯脂解的限速酶的觀點受到了挑戰(zhàn)。
CGI-58是一個主要表達于睪丸和脂肪組織的40 kDa的349氨基酸蛋白[13]。它是ATGL的輔助活化劑,ATGL的脂解作用依賴CGI-58[11,14],反過來,ATGL也是CGI-58調節(jié)脂肪細胞脂解的唯一目標途徑[15]。在基礎狀態(tài)或未刺激條件下,CGI-58與perilipin A緊密結合,不能激活ATGL,在激素刺激下,cAMP升高,PKA激活促使perilipin A磷酸化,CGI-58從perilipin解離,CGI-58與ATGL相互作用,激活甘油三酯水解[16,17]。
有關ATGL激活機制的研究發(fā)現(xiàn),在白色脂肪組織HSL缺乏[6]或抑制條件下[18],機體仍會表現(xiàn)出激素刺激下的脂解反應,這提示我們ATGL 的活化也是直接或間接通過激素信號途徑實現(xiàn)的。但是進一步的研究發(fā)現(xiàn),ATGL激活的分子學機制與HSL也存在一定差異,首先與HSL不同的是在基礎狀態(tài)和激活狀態(tài)下脂滴處的ATGL沒有差別[7];另外,雖然ATGL也可被磷酸化,但不是以PKA為目標[7,19],因此,有關ATGL激活及促脂解的分子學機制還需要研究。
HSL主要促進甘油二酯的分解,人為抑制HSL可降低血漿游離脂肪酸水平[19]。在未刺激條件下,HSL主要分布于胞漿,脂解激素刺激后perilipin和HSL磷酸化,HSL從胞漿轉移到脂滴表面,促使脂解增強[20]。HSL可通過PKA和PKG調節(jié)的磷酸化來促進脂解,也可通過AMP激活蛋白激酶(AMPK)誘導的HSL Ser565位點的磷酸化來抑制PKA對HSL Ser563 位點的作用,抑制脂解[14,21]。
FABP4高度表達于脂肪細胞,可促進脂肪酸攝入、脂解及其脂解后脂肪酸的運輸,F(xiàn)ABP4缺失可影響游離脂肪酸的轉運,脂解減少[22]。HSL包含一個脂肪酸結合位點,當HSL磷酸化后HSL和FABP4結合形成復合物,F(xiàn)ABP4結合一個脂肪酸。通過基因改造對不同F(xiàn)ABP亞型老鼠的研究發(fā)現(xiàn),脂解似乎只與總的FABP濃度有關,而與某種特有FABP亞型似乎沒有關系[23]。
MGL是33 kDa的由302個氨基酸組成的酶,主要在脂肪組織中表達,它是HSL刺激下生成的甘油一酯進一步脂解的必需脂肪酶。除ATGL、HSL、MGL外,可能還存在其它未被發(fā)現(xiàn)的脂肪酶,但是研究發(fā)現(xiàn),在HSL完全抑制條件下,缺乏ATGL的脂肪組織的脂肪酸釋放幾乎完全被抑制[8,11],認為ATGL和HSL在脂肪細胞水解過程中起主要作用。
與激素和旁分泌相關的cAMP與脂解的增強和抑制平衡有關,這個平衡途徑主要通過cAMP和脂肪細胞核苷酸磷酸二酯酶(phosphodiesterases,PDEs)來調節(jié)。腺苷酸環(huán)化酶的激活或抑制通過其受體來實現(xiàn),其興奮性受體與G蛋白偶聯(lián)后,激活腺苷酸環(huán)化酶,cAMP生成增多;抑制性受體與G蛋白偶聯(lián),抑制酶的活性,降低cAMP水平。
兒茶酚胺是人體主要的刺激脂解激素。兒茶酚胺通過與其相應的受體(1-AR、2-AR、3-AR、2AR)結合來調節(jié)脂解,這些受體與三磷酸鳥苷結合調節(jié)G蛋白偶聯(lián),而 腎上腺受體與Gs偶聯(lián),可激活腺苷酸環(huán)化酶,導致cAMP增加,激活PKA[24]。在人類脂肪細胞,1-ARs和2-ARs可刺激cAMP生成,促使脂解,而3-AR是否能促脂解還不能讓人信服,有研究在注入異丙腎上腺素后沒有發(fā)現(xiàn)3-AR調節(jié)的脂解增強以及能量消耗和脂肪氧化增加[25],但也有離體研究發(fā)現(xiàn)3-AR激動劑表現(xiàn)出一定促脂解作用[26]。
通過Gs蛋白偶聯(lián)受體激活PKA的激素還有胰高血糖素[27]、甲狀旁腺激素[28]、促甲狀腺素[29]、促黑素[30]、促腎上腺皮質激素[30],但它們的促脂解作用較小。
兒茶酚胺也可通過2腎上腺受體與Gi偶聯(lián),抑制腺苷酸環(huán)化酶活性,導致PKA活性下降,抑制脂解。其它通過Gi偶聯(lián)抑制脂解的還有腺苷(A1腺苷受體)[31]、前列腺素(E2 受體)[32]、神經(jīng)肽Y(NPY-1 受體)[33]、煙酸(GPR109A 受體)[34]等,它們可通過與屬于G蛋白偶聯(lián)受體家族的相關受體結合,降低腺苷酸環(huán)化酶活性,抑制脂解。最近研究也發(fā)現(xiàn),GPR81是一個在脂肪組織表達的、與煙酸受體GPR109a高度相似的Gi蛋白偶聯(lián)受體,乳酸和琥珀酸鹽可激活該受體,通過Gi相關的腺苷酸環(huán)化酶的下降來抑制脂解[35-37]??偟膩砜?,所有這些內源性抑制性配體在調節(jié)甘油三酯脂解中也具有重要作用,它們的作用可從配體生成、相關酶的降解、Gi偶聯(lián)受體的表達來考慮。
研究已經(jīng)證實靜脈補充心鈉肽(ANP)具有促脂解作用[38,39],但是鈉尿肽家族刺激脂解能力存在差異,ANP、腦鈉肽 (BNP)刺激人體脂肪細胞脂解能力較強,C型鈉尿肽(CNP)促脂解作用很小,刺激脂解能力排序為ANP > BNP > CNP。Lafontan等認為鈉尿肽通過屬于G蛋白偶聯(lián)受體的鈉尿肽受體A(NPR-A)和鈉尿肽受體B(NPR-B),以及cGMP、PKG途徑刺激脂解[40]。作為新發(fā)現(xiàn)的一個促脂解通路,鈉尿肽通路相關調節(jié)機制還需要進一步研究。
胰島素具有很強的抗脂解作用。脂肪細胞、胰島素和胰島素樣生長因子(IGF-1)通過環(huán)核苷酸磷酸二酯酶3B(PDE3B)調節(jié)cAMP水平和脂解[41]。胰島素可激活PDE3B,啟動與PDE3B相關的cAMP降解為5’AMP,cAMP減少,PKA失活,HSL 和perilipins磷酸化減少,抑制脂解。
胰島素和IGF-1受體屬于酪氨酸激酶受體,它們與磷脂酰肌醇3激酶(PI3K)偶聯(lián),PI3K調節(jié)脂質激酶和絲氨酸激酶活性,具體機制相當復雜。已有的研究發(fā)現(xiàn),當胰島素與其受體結合時,通過酪氨酸殘基磷酸化,受體被激活,導致細胞內底物(胰島素受體底物I和II)的酪氨酸磷酸化,并與PI3K的p85亞單位結合,激活脂質激酶,導致在肌醇環(huán)D-3位磷脂酰肌醇磷酸化。另外,PI3K絲氨酸激酶自動磷酸化p85調節(jié)亞基和p110催化亞基,隨后蛋白激酶B磷酸化,PDE3B激活,cAMP分解[42]。
除以上調節(jié)通路外,生長素(GH)、白介素-6(IL-6)、腫瘤壞死因子 (TNF )等其它一些因素也會對脂肪的動員和氧化利用產(chǎn)生一定程度的影響。
研究表明GH可刺激脂肪細胞脂解,且這種作用可被延遲2~3小時,其機制可能是GH通過降低與Gi通路相關的cAMP生成抑制,使cAMP生成增加,從而使脂解增強[43]。局部分泌的IL-6也可通過旁分泌或自分泌機制對脂肪細胞產(chǎn)生作用,IL-6 可通過其受體系統(tǒng)刺激脂肪細胞脂解,重組人IL-6注入可導致血漿游離脂肪酸和甘油濃度升高[44]。另外,TNF 也具有一定的促脂解作用。TNF 可與腫瘤壞死因子受體1(TNFR-1)結合,通過促進脂肪酶的表達、perilipin的磷酸化和表達發(fā)揮促脂解作用,也可通過對胰島素作用和腺苷、前列腺素E、NPY等Gi通路的抑制等來促進脂解[45,46]。
運動導致的脂解增強主要與運動過程中兒茶酚胺(尤其是腎上腺素)[47]、鈉尿肽[38,40]和促腎上腺皮質激素的促脂解作用[30]以及胰島素的抗脂解作用有關,運動誘導的GH和可的松升高可能在運動后脂肪脂解中具有重要作用[48]。而運動過程中IL-6能否發(fā)揮促脂解作用存在一定爭論,有研究認為IL-6在運動過程中具有促脂解作用[44],也有研究發(fā)現(xiàn)在低強度運動同時注入IL-6,脂肪酸氧化并未增強[49]。因此,運動狀態(tài)中IL-6是否具有促脂解作用還有待進一步研究。
低強度(< 30%VO2max)長時間運動過程中,來自脂肪組織的游離脂肪酸是肌肉燃料的主要來源。這可能與運動強度較低、機體能量需求較小、氧供應充足、慢肌纖維募集、脂肪氧化供能能力增強等因素有關。雖然低強度運動不會引起主要的代謝激素發(fā)生顯著改變,但是隨著運動時間延長,血糖濃度下降[50],胰島素下降及對脂解的抑制減弱,脂肪動員增強。
中等強度(40~65%VO2max)長時間運動時,機體仍然主要利用脂肪來供能。在中等強度運動過程中兒茶酚胺升高,ATGL和HSL激活,脂解增強[51-53],而且隨著運動時間延長,血糖水平下降,胰島素下降,脂解抑制減弱,脂解將進一步增強。最近也有研究發(fā)現(xiàn),在30%和50%VO2max強度運動過程中,腹部皮下脂肪組織動員對 腎上腺素受體的依賴性較低,而血漿ANP濃度升高,胰島素下降[54,55]。這似乎提示我們,在中低強度運動過程中鈉尿肽對脂肪動員具有重要作用。
高強度(≥70%VO2max)運動時,機體能量需求速率急劇增加,葡萄糖和糖原成為主要的供能底物,同時,隨著運動強度的增加,乳酸產(chǎn)生增加,可激活GPR81受體(與煙酸受體GPR109a高度相似的抑制性G蛋白偶聯(lián)受體),進而通過抑制性G蛋白偶聯(lián)受體抑制脂解[35-37]。另外,高強度運動時脂肪組織血流減少,影響脂肪酸轉運,導致長鏈脂肪酸進入線粒體減少,這也會對運動時脂肪的動員和氧化利用產(chǎn)生影響[56]。
長期有氧運動訓練可導致機體在基礎狀態(tài)或運動狀態(tài)的脂解能力增強,表現(xiàn)為在基礎狀態(tài)或相同強度運動狀態(tài)的脂肪氧化供能比例增加[57,58]。這種適應性變化,一方面與 腎上腺素受體敏感度增強,提高脂解效果有關[59,60];另一方面也可能與2腎上腺素受體調節(jié)的抗脂解作用不變或減弱有關[61]。Moro等近年來的研究發(fā)現(xiàn),耐力運動過程中ANP的釋放具有促進脂解的作用,訓練導致的機體脂解能力增強與ANP促脂解作用增強有關[62-64]。最近有研究也進一步發(fā)現(xiàn)脂肪組織血流改善對脂肪組織NPR-A 的表達具有調節(jié)作用[65]。因此,訓練導致的機體脂解能力增強與ANP活性增強及皮下脂肪組織血流改善也有密切關系。另外,長期運動訓練導致的可的松和生長素長時間升高,對脂肪動員也有一定作用[66,67],但相比較而言,腎上腺素和ANP以及胰島素的作用更加重要。
到目前為止,有關長期耐力訓練對脂肪酶及相關蛋白表達影響的研究較少。從現(xiàn)有研究來看,有的研究認為長期訓練可上調骨骼肌perilinpin[68]、HSL[69]、ATGL[70]水平,也有研究并未發(fā)現(xiàn)耐力訓練可導致 ATGL[71]和 HSL 表達增加[72]。有關長期耐力訓練對脂解酶及其相關蛋白表達的影響還需要研究。綜合相關理論與已有研究,我們認為長期有氧耐力訓練提高脂肪分解和氧化供能能力的相關調節(jié)機制可能涉及以下幾個方面:(1)機體心肺功能、骨骼肌線粒體體積和數(shù)量以及相關氧化酶活性提高,機體攝氧能力和用氧能力增強。(2)脂肪組織血液循環(huán)改善,脂肪酸和氧運輸增強。(3)相同強度運動乳酸生成減少,乳酸對脂解抑制減弱。(4)促脂解激素受體敏感度增強。(5)脂肪酶及其相關蛋白表達增加。
脂肪動員與脂肪酶ATGL、HSL、MGL的活性及perilipin、CGI-58、FABP4等相關蛋白的功能狀態(tài)有關,而神經(jīng)、激素和血循環(huán)對脂肪動員和氧化利用具有調節(jié)作用,其中兒茶酚胺、鈉尿肽、胰島素、代謝產(chǎn)物(乳酸)等是調節(jié)脂解的主要物質,它們可通過其相應的G蛋白偶聯(lián)受體來增強或抑制脂肪動員。但是相關調控機制還有待人體研究來證實。而運動不僅對脂肪的氧化利用具有直接作用,也可通過神經(jīng)、激素和血循環(huán)對機體的脂肪動員和氧化利用發(fā)揮調節(jié)作用。但到目前為止,對其具體相關調節(jié)機制的研究還很少,有待進一步開展。另外,已有的關于運動與脂肪動員和氧化利用關系的研究主要集中于對運動階段的研究,而中等強度[73]和高強度[74]運動后恢復期存在的脂肪動員和氧化增加提示我們今后還應加強對運動后效應的研究。
[1]Brasaemle DL,Subramanian V,Garcia A,et al. Perilipin A and the control of triacylglycerol metabolism.Mol Cell Biochem,2009,326(1-2):15-21.
[2]Brasaemle DL.Thematic review series:adipocyte biology.The perilipin family of structural lipid droplet proteins:stabilization of lipid droplets and control of lipolysis. J Lipid Res,2007,48(12):2547-2559.
[3]Ducharme NA and Bickel PE. Lipid droplets in lipogenesis and lipolysis.Endocrinology,2008,149(3):942-949.
[4]Krintel C,Morgelin M,Logan DT,et al. Phosphorylation of hormonesensitive lipase by protein kinase A in vitro promotes an increase in its hydrophobic surface area. FEBS J,2009,276(17):4752-4762.
[5]Granneman J,Moore H,Krishnamoorthy R,et al.Perilipin controls lipolysis by regulating the interactions of AB-hydrolase containing 5(Abhd5) and adipose triglyceride lipase(Atgl). J Biol Chem,2009,284(50):34538-34544.
[6]Haemmerle G,Zimmermann R,Hayn M,et al. Hormone-sensitive lipase de ficiency in mice causes diglyceride accumulation in adipose tissue, muscle and testis. J Biol Chem,2002,277(7):4806-4815.
[7]Zimmermann R,Strauss JG,Haemmerle G,et al. Fat mobilization in adipose tissue is promoted by adipose triglyceride lipase. Science,2004,306(5700):1383-1386.
[8]Schweiger M,Schreiber R,Haemmerle G,et al. Adipose triglyceride lipase and hormone-sensitive lipase are the major enzymes in adipose tissue triacylglycerol catabolism. J Biol Chem,2006,281(52):40236-40241.
[9]Haemmerle G,Lass A,Zimmermann R,et al.Defective lipolysis and altered energy metabolism in mice lacking adipose triglyceride lipase. Science,2006,312(5774):734-737.
[10]Ahmadian M,Duncan RE,Varady KA,et al. Adipose overexpression of desnutrin promotes fatty acid use and attenuates diet-induced obesity.Diabetes,2009,58(4):855-866.
[11]Bezaire V,Mairal A,Ribet C,et al. Contribution of adipose triglyceride lipase and hormone-sensitive lipase to lipolysis in hMADS adipocytes. J Biol Chem,2009,284(27):18282-18291.
[12]Schoiswohl G,Schweiger M,Schreiber R,et al.Adipose triglyceride lipase plays a key role in the supply of the working muscle with fatty acids.J Lipid Res,2010,51(3):490-499.
[13]Zechner R,Kienesberger PC,Haemmerle G,et al.Adipose triglyceride lipase and the lipolytic catabolism of cellular fat stores. J Lipid Res,2009,50(1):3-21.
[14]Bezaire V and Langin D. Regulation of adipose tissue lipolysis revisited. Proc Nutr Soc,2009,68(4):350-360.
[15]Lass A,Zimmermann R,Haemmerle G,et al. Adipose triglyceride lipase-mediated lipolysis of cellular fat stores is activated by CGI-58 and defective in Chanarin-Dorfman syndrome. Cell Metab,2006,3(5):309-319.
[16]Miyoshi H,Perfield II JW,Souza SC,et al. Control of adipose triglyceride lipase action by serine 517 of perilipin A globally regulates protein kinase A-stimulated lipolysis in adipocytes. J Biol Chem,2007,282(2):996-1002.
[17]Yamaguchi T,Omatsu N,Morimoto E,et al.CGI-58 facilitates lipolysis on lipid droplets but is not involved in the vesiculation of lipid droplets caused by hormonal stimulation. J Lipid Res,2007,48(5):1078-1089.
[18]Langin D,Laurell H,Holst LS,et al. Gene organization and primary structure of human hormone-sensitive lipase: possible signi ficance of a sequence homology with a lipase of Moraxella TA144, an antarctic bacterium. Proc Natl Acad Sci USA,1993,90(11):4897-4901.
[19]Bartz R,Zehmer JK,Zhu M,et al. Dynamic activity of lipid droplets: protein phosphorylation and GTP-mediated protein translocation. J Proteome Res,2007,6(8):3256-3265.
[20]Brasaemle DL,Levin DM,Adler-Wailes DC,et al.The lipolytic stimulation of 3T3-L1 adipocytes promotes the translocation of hormone-sensitive lipase to the surfaces of lipid storage droplets. Biochim Biophys Acta,2000,1483(2):251-262.
[21]Gaidhu MP,F(xiàn)ediuc S,Anthony NM,et al. Prolonged AICAR-induced AMP-kinase activation promotes energy dissipation in white adipocytes: novel mechanisms integrating HSL and ATGL. J Lipid Res,2009,50(4):704-715.
[22]Furuhashi M and Hotamisligil GS. Fatty acid-binding proteins: role in metabolic diseases and potential as drug targets. Nat Rev Drug Discov,2008,7(6):489-503.
[23]Hertzel AV,Bennaars-Eiden A and Bernlohr DA. Increased lipolysis in transgenic animals overexpressing the epithelial fatty acid binding protein in adipose cells. J Lipid Res,2002,43(12):2105-2111.
[24]Holm C. Molecular mechanisms regulating hormonesensitive lipase and lipolysis. Biochem Soc Trans,2003,31(6):1120-1124.
[25]Barbe P,Millet L,Galitzky J,et al. In situ assessment of the role of the beta 1-, beta 2- and beta 3-adrenoceptors in the control of lipolysis and nutritive blood fl ow in human subcutaneous adipose tissue. Br J Pharmacol,1996,117(5):907-913.
[26]Robidoux J,Kumar N,Daniel KW,et al. Maximal beta3-adrenergic regulation of lipolysis involves Src and epidermal growth factor receptor-dependent ERK1/2 activation. J Biol Chem,2006,281(49):37794-37802.
[27]Bousquet-Melou A,Galitzky J,Lafontan M,et al.Control of lipolysis in intra-abdominal fat cells of nonhuman primates: comparison with humans. J Lipid Res,1995,36(3):451-461.
[28]Taniguchi A,Kataoka K,Kono T,et al. Parathyroid hormone-induced lipolysis in human adipose tissue. J Lipid Res,1987,28(5):490-494.
[29]Marcus C,Ehren H,Bolme P,et al. Regulation of lipolysis during the neonatal period. Importance of thyrotropin. J Clin Invest,1988,82(5):1793-1797.
[30]Lafontan M and Agid R. An extra-adrenal action of adrenocorticotrophin:physiological induction of lipolysis by secretion of adrenocorticotrophin in obese rabbits. J Endocrinol,1979,81(3):281-290.
[31]Larrouy D,Galitzky J and Lafontan M. A1 adenosine receptors in the human fat cell: tissue distribution and regulation of radioligand binding. Eur J Pharmacol,1991,206(2):139-147.
[32]Richelsen B. Release and effects of prostaglandins in adipose tissue. Prostaglandins Leukot Essent Fatty Acids,1992,47(3):171-182.
[33]Bradley RL,Mans field JP and Maratos-Flier E. Neuropeptides,including neuropeptide Y and melanocortins,mediate lipolysis in murine adipocytes. Obes Res,2005,13(4):653-661.
[34]Offermanns S. The nicotinic acid receptor GPR109A(HM74A or PUMA-G)as a new therapeutic target.Trends Pharmacol Sci,2006,27(7):384-390.
[35]Liu C,Wu J,Zhu J,et al. Lactate inhibits lipolysis in fat cells through activation of an orphan G-protein-coupled receptor,GPR81. J Biol Chem,2009,284(5):2811-2822.
[36]Ahmed K,Tunaru S,Tang C,et al. An autocrine lactate loop mediates insulin-dependent inhibition of lipolysis through GPR81. Cell Metab,2010,11(4):311-319.
[37]Rooney K and Trayhurn P. Lactate and the GPR81 receptor in metabolic regulation: implications for adipose tissue function and fatty acid utilisation by muscle during exercise. Br J Nutr,2011,106(9):1310-1316.
[38]Sengenes C,Stich V,Berlan M,et al. Increased lipolysis in adipose tissue and lipid mobilization to natriuretic peptides during low-calorie diet in obese women. Int J Obes Relat Metab Disord,2002,26(1):24-32.
[39]Birkenfeld AL,Boschmann M,Moro C,et al. Lipid mobilization with physiological atrial natriuretic peptide concentrations in humans. J Clin Endocrinol Metab,2005,90(6):3622-3628.
[40]Lafontan M,Moro C,Berlan M,et al. Control of lipolysis by natriuretic peptides and cyclic GMP. Trends Endocrinol Metab,2008,19(4):130-137.
[41]Choi YH,Park S,Hockman S,et al. Alterations in regulation of energy homeostasis in cyclic nucleotide phosphodiesterase 3B-null mice. J Clin Invest,2006,116(12):3240-3251.
[42]Saltiel AR and Pessin JE. Insulin signaling pathways in time and space. Trends Cell Biol,2002,12(2):65-71.
[43]Yip RG and Goodman HM. Growth hormone and dexamethasone stimulate lipolysis and activate adenylyl cyclase in rat adipocytes by selectively shifting Gi alpha2 to lower density membrane fractions. Endocrinology,1999,140(3):1219-1227.
[44]van Hall G,Steenberg A,Sacchetti M,et al. Interleukin-6 stimulates lipolysis and fat oxidation in humans. J Clin Endocrinol Metab,2003,88(7):3005-3010.
[45]Zhang HH,Halbleib M,Ahmad F,et al. Tumor necrosis factor-alpha stimulates lipolysis in differentiated human adipocytes through activation of extracellular signal-related kinase and elevation of intracellular cAMP.Diabetes,2002,51(10):2929-2935.
[46]Sethi J,Xu H,Uysal KT,et al. Characterisation of receptor-speci fic TNFalpha functions in adipocyte cell lines lacking type 1 and 2 TNF receptors. FEBS Lett,2000,469(1):77-82.
[47]De I,Larrouy D,Bajzova M,et al. Adrenaline but not noradrenaline is a determinant of exercise-induced lipid mobilization in human subcutaneous adipose tissue. J Physiol,2009,587(13):3393-3404.
[48]Enevoldsen LH,Polak J,Simonsen L,et al. Postexercise abdominal, subcutaneous adipose tissue lipolysis in fasting subjects is inhibited by infusion of the somatostatin analogue octreotide. Clin Physiol Funct Imaging,2007,27(5):320-326.
[49]Hiscock N,F(xiàn)ischer CP,Sacchetti M,et al. Recombinant human interleukin-6 infusion during low-intensity exercise does not enhance whole body lipolysis or fat oxidation in humans. Am J Physiol Endocrinol Metab,2005,289(1):E2-7.
[50]Jeukendrup AE,Saris WHM and Wagenmakers AJM.Fat metabolism during exercise:a review.part I:fatty acid mobilizationand muscle metabolism. Int J Sports Med,1998,19(4):231-244.
[51]Jeukendrup AE,Saris WHM and Wagenmakers AJM.Fat metabolism during exercise:a review–part II:regulation of metabolism and the effects of training. Int J Sports Med,1998,19(5):293-302.
[52]Frayn KN. Fat as a fuel: emerging understanding of the adipose tissue-skeletal muscle axis. Acta Physiol( Oxf),2010,199(4):509-518.
[53]Kiens B,Alsted TJ and Jeppesen J. Factors regulating fat oxidation in human skeletal muscle. Obes Rev,2011,12(10):852-858.
[54]Moro C,Pillard F,De Glisezinski I,et al. Sex differences in lipolysis-regulating mechanisms in overweight subjects: effect of exercise intensity. Obesity,2007,15(9):2245-2255.
[55]Koppo K,Larrouy D,Marques MA,et al. Lipid mobilization in subcutaneous adipose tissue during exercise in lean and obese humans. Roles of insulin and natriuretic peptides. Am J Physiol Endocrinol Metab,2010,299(2):E258-265.
[56]Pelsers MM,Stellingwerff T and van Loon LJ. The role of membrane fatty-acid transporters in regulating skeletal muscle substrate use during exercise. Sports Med,2008,38(5):387-399.
[57]Coggan AR,Raguso CA,Gastaldelli A,et al. Fat metabolism during high-intensity exercise in endurancetrained and untrained men. Metabolism,2000,49(1):122-128.
[58]Amati F,Dubé JJ,Alvarez-Carnero E,et al. Skeletal muscle triglycerides, diacylglycerols, and ceramides in insulin resistance:another paradox in endurance-trained athletes? Diabetes,2011,60(10):2588-2597.
[59]De Glisezinski I,Crampes F,Harant I,et al. Endurance training changes in lipolytic responsiveness of obese adipose tissue. Am J Physiol,1998,275(6 Pt 1):E951-956.
[60]Stich V,De Glisezinski I,Galitzky J,et al. Endurance training increases the beta-adrenergic lipolytic response in subcutaneous adipose tissue in obese subjects. Int J Obes,1999,23(4):374-381.
[61]De Glisezinski I,Marion-Latard F,Crampes F,et al.Lack of alpha2-adrenergic antilipolytic effect during exercise in subcutaneous adipose tissue of trained men. J Appl Physiol,2001,91(4):1760-1765.
[62]Moro C,Pillard F,De Glisezinski I,et al.Training enhances ANP lipid-mobilizing action in adipose tissue of overweight men. Med Sci Sports Exerc,2005,37(7):1126-1132.
[63]Moro C,Crampes F,Sengenes C,et al. Atrial natriuretic peptide contributes to physiological control of lipid mobilization in humans. FASEB J,2004,18(7):908-910.
[64]Moro C,Polak J,Hejnova J,et al. Atrial natriuretic peptide stimulates lipid mobilization during repeated bouts of endurance exercise. Am J Physiol Endocrinol Metab,2006,290(5):E864–869.
[65]Perez-Matute P,Neville MJ,Tan GD,et al. Transcriptional control of human adipose tissue blood fl ow. Obesity,2009,17(4):681-688.
[66]Campbell JE,F(xiàn)ediuc S,Hawke TJ,et al. Endurance exercise training increases adipose tissue glucocorticoid exposure:adaptations that facilitate lipolysis. Metabolism,2009,58(5):651-660.
[67]Djurhuus CB,Gravholt CH,Nielsen S,et al. Additive effects of cortisol and growth hormone on regional and systemic lipolysis in humans. Am J Physiol Endocrinol Metab,2004,286(3):E488-494.
[68]Petridou A,Tsalouhidou S,Tsalis G,et al. Long-term exercise increases the DNA binding activity of peroxisome proliferator-activated receptor gamma in rat adipose tissue. Metabolism,2007,56(8):1029-1036.
[69]Talanian JL,Galloway SD,Heigenhauser GJ,et al.Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women.J Appl Physiol,2007,102(4):1439-1447.
[70]Alsted TJ,Nybo L,Schweiger M,et al. Adipose triglyceride lipase in human skeletal muscle is upregulated by exercise training. Am J Physiol Endocrinol Metab,2009,296(3):E445-453.
[71]Nielsen TS,Vendelbo MH,Jessen N,et al. Fasting,but not exercise,increases adipose triglyceride lipase(ATGL)protein and reduces G(0)/G(1)switch gene 2(G0S2)protein and mRNA content in human adipose tissue. J Clin Endocrinol Metab,2011,96(8):E1293-1297.
[72]Helge JW,Biba TO,Galbo H,et al. Muscle triacylglycerol and hormone-sensitive lipase activity in untrained and trained human muscles. Eur J Appl Physiol,2006,97(5):566-572.
[73]Ogasawara J,Nomura S,Rahman N,et al. Hormonesensitive lipase is critical mediators of acute exerciseinduced regulation of lipolysis in rat adipocytes. Biochem Biophys Res Commun,2010,400(1):134-139.
[74]Yoshioka M,Doucet E,St-Pierre S,et al. Impact of high intensity exercise on energy expenditure, lipid oxidation and body fatness. Int J Obes Relat Metab Disord,2001,25(3):332-339.