title: Fenugreek increases insulin-stimulated creatine content in L6C11 muscle myotubes.
abstract: OBJECTIVE
  Creatine uptake by muscle cells is increased in the presence of insulin. Accordingly, compounds with insulin-like actions may also augment creatine uptake. The aim of this study was to investigate whether Trigonella foenum-graecum (fenugreek), an insulin mimetic, increases total intracellular creatine levels in vitro.
  
  
  METHODS
  Total cellular creatine content was measured fluorometrically in L6C11 muscle myotubes treated for 1, 4, and 24 h with 0.5 mM creatine (CR), CR and 20 μg/mL fenugreek seed extract (CR + FEN), CR and 100 nM insulin (CR + INS), and CR + INS + FEN (n = 6 per treatment group). Alterations in the expression of the sodium- and chloride-dependent creatine transporter, SLC6A8, and key signaling proteins in the PI3-K/Akt pathway were determined.
  
  
  RESULTS
  Compared to control (CON), CR + INS + FEN increased total creatine content after 4 h (P < 0.05), whereas all conditions increased SLC6A8 protein expression above CON at this time (P < 0.05). Changes in insulin signaling were demonstrated via increases in AktThr308phosphorylation, with CR + INS > CON and CR at 1 h (P < 0.05) and with CR + INS + FEN > CON, CR, and CR + INS at 4 h (P < 0.05). In contrast, no changes in PKCζ/λ or GLUT4 phosphorylation were detected.
  
  
  CONCLUSIONS
  Fenugreek, when combined with insulin, modulates creatine content via a mechanism which is independent of the activity of SLC6A8, suggesting that an alternative mechanism is responsible for the regulation and facilitation of insulin-mediated creatine uptake in skeletal muscle cells.
authors.affiliation: Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia.
authors.forename: Kristyen A
authors.initials: KA
authors.lastname: Tomcik
authors.affiliation: Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia.
authors.forename: William J
authors.initials: WJ
authors.lastname: Smiles
authors.affiliation: Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia.
authors.forename: Donny M
authors.initials: DM
authors.lastname: Camera
authors.affiliation: School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia.
authors.forename: Helmut M
authors.initials: HM
authors.lastname: Hügel
authors.affiliation: Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia. john.hawley@acu.edu.au.|Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. john.hawley@acu.edu.au.
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
authors.affiliation: Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia.
authors.forename: Rani
authors.initials: R
authors.lastname: Watts
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival; D003401:Creatine / Q000378:metabolism*; D005786:Gene Expression Regulation; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D050480:Plasma Membrane Neurotransmitter Transport Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D029910:Trigonella / Q000737:chemistry
chemical_list: D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D009419:Nerve Tissue Proteins; D010936:Plant Extracts; D050480:Plasma Membrane Neurotransmitter Transport Proteins; C495694:Slc2a4 protein, rat; C075746:Slc6a8 protein, rat; C056164:fenugreek seed meal; D019869:Phosphatidylinositol 3-Kinases; D003401:Creatine
keywords: Creatine content; Creatine transport; Fenugreek supplement; Insulin signaling