scholarly journals Stimulation of adipocyte phospholipid methyltransferase activity by phorbol 12-myristate 13-acetate. Differential regulation of phospholipid methyltransferase and lipolysis

1987 ◽  
Vol 241 (3) ◽  
pp. 917-921 ◽  
Author(s):  
K L Kelly
Keyword(s):  
Phorbol Esters ◽  
Inhibitory Effect ◽  
Differential Regulation ◽  
Hormone Sensitive Lipase ◽  
Regulatory Pathway ◽  
Methyltransferase Activity ◽  
Hormone Sensitive ◽  
Intracellular Target ◽  
Dose Dependent ◽  
Stimulation Of

The present studies demonstrate that treatment of rat adipocytes with the phorbol ester phorbol 12-myristate 13-acetate (PMA) causes a dose-dependent stimulation of phospholipid methyltransferase (PLMT) activity. The stimulatory effect of PMA was not additive with that of isoprenaline or forskolin. The sensitivity of stimulated PLMT activity to inhibition by insulin, however, was decreased in the presence of PMA. The inhibitory effect of a maximal concentration of insulin on PLMT was unchanged in the presence of PMA. In contrast with the effects on PLMT, the lipolytic response of adipocytes to isoprenaline and the anti-lipolytic response to insulin were unaffected by PMA. These data suggest that PLMT is, whereas hormone-sensitive lipase is not, an intracellular target for the action of PMA. The lack of effect of PMA on lipolysis suggests that PLMT and hormone-sensitive lipase can be regulated by separate mechanisms. Furthermore, phorbol esters do not interfere in the regulatory pathway whereby insulin inhibits PMLT or lipolysis.

PKC-independent inhibition of cardiac L-type Ca2+ channel current by phorbol esters

1996 ◽  
Vol 270 (2) ◽  
pp. H620-H627 ◽  
Author(s):  
T. Asai ◽  
L. M. Shuba ◽  
D. J. Pelzer ◽  
T. F. McDonald
Keyword(s):  
Protein Kinase C ◽  
Phorbol Esters ◽  
Ventricular Myocytes ◽  
Inhibitory Effect ◽  
Independent Action ◽  
Independent Manner ◽  
Channel Current ◽  
Kinase C ◽  
Channel Currents ◽  
Stimulation Of

Active and inactive phorbol esters were applied to guinea pig ventricular myocytes to study the responses of L-type Ca2+ (ICa,L) and L-type Na+ (INa,L) currents. Phorbol 12-myristate 13-acetate (PMA) (10-100 rM) never stimulated ICa,L or INa,L and frequently depressed them by 5-30% in a voltage-independent manner. However, the phorbol ester consistently activated delayed-rectifying K+ (IK) and Cl- currents. The inhibition of ICa,L occurred approximately 3 times faster than comonitored stimulation of IK, and ICa,L and INa,L were unaffected by two interventions that suppressed IK stimulation [pretreatment with 50 microM 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and dialysis with pCa 11 versus standard pCa 9 solution]. Inactive phorbol esters 4 alpha-phorbol 12,13-didecanoate (alpha-PDD) and 4 alpha-phorbol had little effect on IK, but alpha-PDD had a PMA-like inhibitory effect on Ca2+ channel currents. We conclude that, unlike the stimulation of IK by PMA, inhibition of Ca2+ channel current by phorbol esters is a protein kinase C-independent action.

scholarly journals Stimulation of Lipolysis and Hormone-sensitive Lipase via the Extracellular Signal-regulated Kinase Pathway

2001 ◽  
Vol 276 (48) ◽  
pp. 45456-45461 ◽  
Author(s):  
Andrew S. Greenberg ◽  
Wen-Jun Shen ◽  
Kizito Muliro ◽  
Shailja Patel ◽  
Sandra C. Souza ◽  
...  
Keyword(s):  
Hormone Sensitive Lipase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Hormone Sensitive ◽  
Kinase Pathway ◽  
Stimulation Of

Regulation of PI hydrolysis and cAMP formation by muscarinic M3 receptor in guinea pig gallbladder

1994 ◽  
Vol 267 (4) ◽  
pp. G523-G528
Author(s):  
T. Takahashi ◽  
S. Kurosawa ◽  
C. Owyang
Keyword(s):  
Guinea Pig ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Biochemical Responses ◽  
Muscarinic Receptor Antagonists ◽  
M3 Receptor ◽  
Pi Hydrolysis ◽  
Dose Dependent ◽  
Camp Formation ◽  
Stimulation Of

Carbachol (10(-8)-10(-3) M) produced two distinct biochemical responses in the guinea pig gallbladder smooth muscle: simulation of phosphoinositide (PI) hydrolysis and inhibition of forskolin-mediated adenosine 3',5'-cyclic monophosphate (cAMP) formation in a dose-dependent manner. The mean effective dose (ED50) concentration (1.6 x 10(-5) M) of carbachol-mediated stimulation of PI hydrolysis was 145 times greater than the ED50 concentration (1.1 x 10(-7) M) of carbachol mediated inhibition of cAMP formation. The inhibitory effect of carbachol on cAMP formation was antagonized by the pretreatment of pertussis toxin. To determine whether these two biochemical responses were mediated by the same or different subtypes of muscarinic receptors, the relative potencies of muscarinic receptor antagonists were calculated by Schild analysis. The M3 muscarinic antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) exhibited inhibitory constant (Ki) values at 0.3 and 1.2 nM in antagonizing the stimulation of PI hydrolysis and the inhibition of cAMP formation, respectively. The corresponding Ki values for pirenzepine, a muscarinic M1 antagonist, were 11 and 130 nM. The corresponding Ki values for AF-DX 116, a muscarinic M2 antagonist, were 34 and 450 nM. Thus 4-DAMP was 37x and 108x more potent than pirenzepine in antagonizing the stimulation of PI hydrolysis and the inhibition of cAMP formation, respectively. In addition, compared with AF-DX 116, 4-DAMP was 113x and 375x more potent in reducing stimulation of PI hydrolysis and inhibition of cAMP formation. Cholecystokinin (CCK) octapeptide (10(-10)-(10-6) M) caused a significant increase of PI hydrolysis but had no inhibitory effects on cAMP formation evoked by forskolin (10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effect of Gambisan on the Inhibition of Adipogenesis in 3T3-L1 Adipocytes

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jung Won Kang ◽  
Dongwoo Nam ◽  
Kun Hyung Kim ◽  
Jeong-Eun Huh ◽  
Jae-Dong Lee
Keyword(s):  
Dna Content ◽  
Hormone Sensitive Lipase ◽  
Dependent Manner ◽  
Rt Pcr ◽  
Hormone Sensitive ◽  
Ldh Assay ◽  
Dose Dependent ◽  
Oil Red O Staining ◽  
Oil Red O

This study was conducted to explore the antiadipogenic effect and possible mechanism of Gambisan on 3T3-L1 cells. For quality control, Gambisan was standardized by HPLC and the standard compounds ephedrine, epigallocatechin-3-gallate, and caffeine were screened. Cultured 3T3-L1 cells that had been induced to differentiate were treated with various concentrations of Gambisan or its major component extracts (Ephedra intermediaSchrenk,Atractylodes lanceaDC., andThea sinensisL.) for 72 hours for MTT assay to determine cell viability or 10 days for LDH assay, triglyceride assay, DNA content measurement, Oil red O staining, RT-PCR, and western blot. Gambisan significantly inhibited adipogenesis in 3T3-L1 cells by reducing triglyceride contents and lipid accumulation in a dose-dependent manner without obvious cytotoxicity. Viability and DNA content in 3T3-L1 cells treated with Gambisan were significantly higher than cells treated with the major component extracts at every concentration. The anti-adipogenic effects of Gambisan appeared to be mediated by a significant downregulation of the expression of lipoprotein lipase mRNA and PPARγ, C/EBPα, and SREBP-1 protein apart from the expression of hormone-sensitive lipase. Gambisan could act as a possible therapeutic agent for obesity. However, further studies includingin vivoassays and clinical trials are needed to confirm the efficacy, safety and mechanisms of the antiobesity effects of Gambisan.

scholarly journals Crotonis Fructusand Its Constituent, Croton Oil, Stimulate Lipolysis in OP9 Adipocytes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Mi-Seong Kim ◽  
Ha-Rim Kim ◽  
Hong-Seob So ◽  
Young-Rae Lee ◽  
Hyoung-Chul Moon ◽  
...  
Keyword(s):  
Positive Control ◽  
Hormone Sensitive Lipase ◽  
Dependent Manner ◽  
Glycerol Release ◽  
Croton Oil ◽  
Croton Tiglium ◽  
Hormone Sensitive ◽  
Main Component ◽  
Culture Supernatants ◽  
Dose Dependent

Introduction. Crotonis fructus (CF) is the mature fruit ofCroton tigliumL. and has been used for the treatment of gastrointestinal disturbance in Asia. It is well known that the main component of CF is croton oil (CO). The present study is to investigate the effects of CF extracts (CFE) and CO on lipolysis in OP9 adipocytes.Methods. Glycerol release to the culture supernatants was used as a marker of adipocyte lipolysis.Results. Treatment with various concentrations of CFE and CO stimulates glycerol release in a dose-dependent manner. The increase in glycerol release by CFE is more potent than isoproterenol, which is aβ-adrenergic agonist as a positive control in our system. The increased lipolysis by CFE and CO was accompanied by an increase of phosphorylated hormone sensitive lipase (pHSL) but not nonphosphorylated HSL protein and mRNA. Pretreatment with H89, which is a protein kinase A inhibitor, significantly abolished the CFE- and CO-induced glycerol release in OP9 adipocytes. These results suggest that CFE and CO may be a candidate for the development of a lipolysis-stimulating agent in adipocytes.

Redox regulation of hormone sensitive lipase: Potential role in the mechanism of MEHP-induced stimulation of basal steroid synthesis in MA-10 Leydig cells

2019 ◽  
Vol 85 ◽  
pp. 19-25 ◽  
Author(s):  
Christine Zhou ◽  
Ninad Zaman ◽  
Yunbo Li ◽  
Daniel B. Martinez-Arguelles ◽  
Vassilios Papadopoulos ◽  
...  
Keyword(s):  
Leydig Cells ◽  
Redox Regulation ◽  
Potential Role ◽  
Hormone Sensitive Lipase ◽  
Steroid Synthesis ◽  
Hormone Sensitive ◽  
Stimulation Of

scholarly journals Tumour-promoting phorbol esters increase basal and inhibit insulin-stimulated lipogenesis in rat adipocytes without decreasing insulin binding

1985 ◽  
Vol 225 (2) ◽  
pp. 523-527 ◽  
Author(s):  
G van de Werve ◽  
J Proietto ◽  
B Jeanrenaud
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Action ◽  
Phorbol Esters ◽  
Insulin Binding ◽  
Rat Adipocytes ◽  
Kinase C ◽  
Dose Dependent ◽  
Isolated Rat ◽  
Stimulation Of

In isolated rat adipocytes, tumour-promoting phorbol esters caused (1) dose-dependent stimulation of lipogenesis in the absence of insulin and (2) inhibition of the lipogenic effect of submaximal concentrations of insulin, but without affecting insulin binding. The possible involvement of protein kinase C in insulin action is discussed.

scholarly journals Translocation of Hormone-sensitive Lipase and Perilipin upon Lipolytic Stimulation of Rat Adipocytes

2000 ◽  
Vol 275 (7) ◽  
pp. 5011-5015 ◽  
Author(s):  
Gary M. Clifford ◽  
Constantine Londos ◽  
Fredric B. Kraemer ◽  
Richard G. Vernon ◽  
Stephen J. Yeaman
Keyword(s):  
Hormone Sensitive Lipase ◽  
Rat Adipocytes ◽  
Hormone Sensitive ◽  
Stimulation Of

Activation of nucleotide oligomerization domain containing protein 1 induces lipolysis through NF-κB and the lipolytic PKA activation in 3T3-L1 adipocytes

2013 ◽  
Vol 91 (6) ◽  
pp. 428-434 ◽  
Author(s):  
Jaanki S. Purohit ◽  
Pan Hu ◽  
Guoxun Chen ◽  
Jay Whelan ◽  
Naima Moustaid-Moussa ◽  
...  
Keyword(s):  
Hormone Sensitive Lipase ◽  
Dependent Manner ◽  
Camp Production ◽  
Nucleotide Oligomerization ◽  
Hormone Sensitive ◽  
Sirna Knockdown ◽  
Dose Dependent ◽  
Nucleotide Oligomerization Domain ◽  
Oligomerization Domain

Obesity is associated with chronic inflammation. Toll-like receptors (TLR) and NOD-like receptors (NLR) are two families of pattern recognition receptors that play important roles in the immune response and inflammation in adipocytes. Activation of TLR4 has been shown to stimulate lipolysis from adipose tissue or adipocytes. However, effects of activation of nucleotide-oligomerization domain containing protein 1 (NOD1), one of the prominent members of NLRs, on adipocyte lipolysis have not been studied. Here we report that NOD1 activation by the synthetic ligands (Tri-DAP and C12-iEDAP) stimulated lipolysis in 3T3-L1 adipocytes in a time- and dose-dependent manner. C12-iEDAP-induced lipolysis was attenuated with NOD1 siRNA knockdown, demonstrating the specificity of the effects. Moreover, inhibition of the protein kinase A (PKA)/hormone sensitive lipase (HSL) and NF-κB pathways by the pharmacological inhibitors attenuated the lipolytic effects of C12-iEDAP. Furthermore, we show NOD1 activation induced PKA activation independent of cAMP production and inhibition of NF-κB pathways attenuated phosphorylation of selected PKA lipolytic targets (phosphorylation of Perilipin Ser 517 and HSL Ser 563). Taken together, our results demonstrate a novel role of NOD1 activation, via NF-κB/PKA lipolytic activation, in inducing lipolysis in adipocytes and suggest that NOD1 activation may contribute to dyslipidemia in obesity.

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