scholarly journals Expression of hormone-sensitive lipase and its regulation by adrenaline in skeletal muscle

1999 ◽  
Vol 340 (2) ◽  
pp. 459-465 ◽  
Author(s):  
Jozef LANGFORT ◽  
Thorkil PLOUG ◽  
Jacob IHLEMANN ◽  
Michele SALDO ◽  
Cecilia HOLM ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Soleus Muscle ◽  
Lipase Activity ◽  
Glycogen Phosphorylase ◽  
Hormone Sensitive Lipase ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Hormone Sensitive ◽  
Neutral Lipase

The enzymic regulation of triacylglycerol breakdown in skeletal muscle is poorly understood. Western blotting of muscle fibres isolated by collagenase treatment or after freeze-drying demonstrated the presence of immunoreactive hormone-sensitive lipase (HSL), with the concentrations in soleus and diaphragm being more than four times the concentrations in extensor digitorum longus and epitrochlearis muscles. Neutral lipase activity determined under conditions optimal for HSL varied directly with immunoreactivity. Expressed relative to triacylglycerol content, neutral lipase activity in soleus muscle was about 10 times that in epididymal adipose tissue. In incubated soleus muscle, both neutral lipase activity against triacylglycerol (but not against a diacylglycerol analogue) and glycogen phosphorylase activity increased in response to adrenaline (epinephrine). The lipase activation was completely inhibited by anti-HSL antibody and by propranolol. The effect of adrenaline could be mimicked by incubation of crude supernatant from control muscle with the catalytic subunit of cAMP-dependent protein kinase, while no effect of the kinase subunit was seen with supernatant from adrenaline-treated muscle. The results indicate that HSL is present in skeletal muscle and is stimulated by adrenaline via β-adrenergic activation of cAMP-dependent protein kinase. The concentration of HSL is higher in oxidative than in glycolytic muscle, and the enzyme is activated in parallel with glycogen phosphorylase.

Stimulation of hormone-sensitive lipase activity by contractions in rat skeletal muscle

2000 ◽  
Vol 351 (1) ◽  
pp. 207-214 ◽  
Author(s):  
Jozef LANGFORT ◽  
Thorkil PLOUG ◽  
Jacob IHLEMANN ◽  
Cecilia HOLM ◽  
Henrik GALBO
Keyword(s):  
Skeletal Muscle ◽  
Lipase Activity ◽  
Glycogen Phosphorylase ◽  
Time Course ◽  
Total Activity ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Neutral Lipase ◽  
Glycogen Phosphorylase Activity ◽  
Muscle Triglyceride

Because the enzymic regulation of muscle triglyceride breakdown is poorly understood we studied whether neutral lipase in skeletal muscle is activated by contractions. Incubated soleus muscles from 70 g rats were electrically stimulated for 60min. Neutral lipase activity against triacylglycerol increased after 1 and 5min of contractions [0.36±0.02 (basal) versus 0.49±0.05 (1min) and 0.54±0.05 (5min) m-unit·mg of protein-1, means±S.E.M., P < 0.05]. After 10min the neutral lipase activity (0.40±0.05m-unit·mg of protein-1) had decreased to basal values (P > 0.05). The contraction-mediated increase in lipase activity was increased by ≈ 110% when muscle was stimulated in the presence of okadaic acid. Conversely, treatment of muscle homogenate with alkaline phosphatase completely reversed the contraction-mediated lipase activation. Lipase activity did not change during contractions when analysed in the presence of anti-hormone-sensitive-lipase (HSL) antibody [0.17±0.02 (basal) versus 0.21±0.02 (5min) m-unit·mg of protein-1, P > 0.05]. Furthermore, immunoprecipitation with affinity-purified anti-HSL antibody reduced muscle-HSL protein concentration by 81±4% and caused similar reductions in lipase activity against triacylglycerol and in the contraction-induced increase in this activity. Neither prior sympathectomy [0.33±0.02 (basal) versus 0.53±0.06 (5min) m-unit·mg of protein-1, P < 0.05] nor propranolol impaired the lipase response to contractions. Glycogen phosphorylase activity in the absence of AMP increased after 1min [27.3±3.1 versus 8.9±1.8% (activity without AMP/total activity with AMP), P < 0.05] and returned to basal levels after 5min. In conclusion, skeletal-muscle-immunoreactive HSL is transiently stimulated by contractions and the mechanism probably involves phosphorylation. The time course of HSL activation is similar to that of glycogen phosphorylase. Apparently, the two enzymes are regulated in parallel by contraction-induced as well as hormonal mechanisms, allowing simultaneous recruitment of all major extra- and intra-muscular energy stores.

scholarly journals Regulation and role of hormone-sensitive lipase in rat skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Morten Donsmark ◽  
Jozef Langfort ◽  
Cecilia Holm ◽  
Thorkil Ploug ◽  
Henrik Galbo
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Energy Content ◽  
Hormone Sensitive Lipase ◽  
Fibre Types ◽  
Muscle Fibre Types ◽  
Muscle Fibres ◽  
Energy Store ◽  
Hormone Sensitive ◽  
Neutral Lipase

Intramyocellular triacylglycerol (TG) is an important energy store, and the energy content of this depot is higher than the energy content of the muscle glycogen depot. It has recently been shown that the mobilization of fatty acids from this TG pool may be regulated by the neutral lipase hormone-sensitive lipase (HSL). This enzyme is known to be rate limiting for intracellular TG hydrolysis in adipose tissue. The presence of HSL has been demonstrated in all muscle fibre types by Western blotting of muscle fibres isolated by collagenase treatment or after freeze-drying. The content of HSL varies between fibre types, being higher in oxidative fibres than in glycolytic fibres. When analysed under conditions optimal for“ HSL, neutral lipase activity in muscle can be stimulated by adrenaline as well as by contractions. These increases are abolished by the presence of anti-HSL antibody during analysis. Moreover, immunoprecipitation with affinity-purified anti-HSL antibody causes similar reductions in muscle HSL protein concentration and in measured neutral lipase responses to contractions. The immunoreactive HSL in muscle is stimulated by adrenaline via β-adrenergic activation of cAMP-dependent protein kinase (PKA). From findings in adipocytes it is likely that PKA phosphorylates HSL at residues Ser563, Ser659and Ser660. Contraction probably also enhances muscle HSL activity by phosphorylation, because the contraction-induced increase in HSL activity is elevated by the protein phosphatase inhibitor okadaic acid and reversed by alkaline phosphatase. A novel signalling pathway in muscle by which HSL activity may be stimulated by protein kinase C (PKC) via extracellular signal-regulated kinase (ERK) has been demonstrated. In contrast to previous findings in adipocytes, in muscle the activation of ERK is not necessary for stimulation of HSL by adrenaline. However, contraction-induced HSL activation is mediated by PKC, at least partly via the ERK pathway. In fat cells ERK is known to phosphorylate HSL at Ser600. Hence, phosphorylation of different sites may explain the finding that in muscle the effects of contractions and adrenaline on HSL activity are partially additive. In line with the view that the two stimuli act by different mechanisms, training increases contraction-mediated HSL activation but diminishes adrenaline-mediated HSL activation in muscle. In conclusion, HSL is present in skeletal muscle and can be activated by phosphorylation in response to both adrenaline and muscle contractions. Training increases contraction-mediated HSL activation, but decreases adrenaline-mediated HSL activation in muscle.

Control of glycogenosis and effects of exercise on phosphorylase kinase and cAMP-dependent protein kinase in rainbow trout organs

1993 ◽  
Vol 71 (11-12) ◽  
pp. 501-506 ◽  
Author(s):  
Hussein Mehrani ◽  
Kenneth B. Storey
Keyword(s):  
Skeletal Muscle ◽  
Rainbow Trout ◽  
Protein Kinase ◽  
Oncorhynchus Mykiss ◽  
Glycogen Phosphorylase ◽  
White Muscle ◽  
Swimming Exercise ◽  
Phosphorylase Kinase ◽  
Dependent Protein Kinase ◽  
Dependent Protein

To analyze the mechanisms of glycogen phosphorylase control in organs of the rainbow trout Oncorhynchus mykiss, activities of glycogen phosphorylase kinase (GPK) and cAMP-dependent protein kinase (PKA), as well as levels of cAMP, were quantified. The complete cascade for activating glycogen phosphorylase was present in trout organs and all components were activated in white skeletal muscle and liver during exhaustive swimming exercise. GPK and PKA showed the highest activities in the liver, being three- and four-fold higher than corresponding activities in white muscle. Exercise stimulated a 60% increase in GPK activity in the liver and a 40% rise in white muscle. Furthermore, the amount of active PKA rose from 12 to 21% in the liver and from 32 to 57% in white muscle after exhaustive exercise and the cellular levels of cAMP increased by 50% in the liver and 70% in white muscle of exercised fish. Other organs (heart, gill, brain, kidney) showed little or no change in these parameters as a result of exhaustive exercise. GPK activity in liver, muscle, and heart extracts was strongly stimulated by in vitro incubation with the catalytic subunit of mammalian PKA, activity rising by 6- to 7-fold in white muscle extracts and 2- to 2.6-fold in liver and heart extracts. This occurred in extracts from both control and exercised fish and suggested that even in fish exercised to exhaustion, the maximal enzymatic potential for activation of glycogenolysis was not expressed. Other modes of GPK activation were not apparent, for the enzyme in crude extracts was stimulated only by incubation with cAMP and did not respond to cGMP or Ca2+ + phorbol 12-myristate 13-acetate. The data indicate that the cAMP-activated, PKA- and GPK-mediated cascade is key to the activation of glycogenolysis in both the skeletal muscle and liver during burst swimming exercise by trout.Key words: exercise, glycogen phosphorylase kinase, protein kinase A, cAMP, Oncorhynchus mykiss, control of glycogenolysis.

Primary structure of the site on bovine hormone-sensitive lipase phosphorylated by cyclic AMP-dependent protein kinase

FEBS Letters ◽  
1988 ◽  
Vol 229 (1) ◽  
pp. 68-72 ◽  
Author(s):  
Andrew J. Garton ◽  
David G. Campbell ◽  
Philip Cohen ◽  
Stephen J. Yeaman
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Primary Structure ◽  
Hormone Sensitive Lipase ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Hormone Sensitive

scholarly journals Hormone-sensitive lipase in differentiated 3T3-L1 cells and its activation by cyclic AMP-dependent protein kinase.

1981 ◽  
Vol 78 (2) ◽  
pp. 732-736 ◽  
Author(s):  
M. Kawamura ◽  
D. F. Jensen ◽  
E. V. Wancewicz ◽  
L. L. Joy ◽  
J. C. Khoo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Hormone Sensitive Lipase ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Hormone Sensitive
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