Ljós fita verður að brúnni

Skrifað um December 9, 2014 · in Almennt · 67 Comments

Tvenns konar fituvefur er í mönnum (og reyndar öllum öðrum spendýrum): Ljós fituvefur og brúnn fituvefur. Ljósa fitan geymir orkugæf efni, sem nýtast í öndunarefnaskiptum líkamans, þegar hann þarf á þeim að halda, sem er nú sjaldan nú orðið. Einnig ver hún líkamann gegn kulda. Brúna fitan aftur á móti sér um myndun á varma, enda er mikið af hvatberum að finna í henni. Þá fitu er einkum að finna í reifabörnum, sem geta ekki varizt kulda á sama hátt og fullorðnir. Talsverður munur er á þessum tveimur gerðum vefja. Ljósu fitufrumurnar eru með eina stóra fitubólu í sér, sem nemur um 85% af rúmfangi frumunnar. Brúnu fitufrumurnar eru minni og í þeim eru margar smáar fitubólur og í talsvert minna mæli en í hinum ljósu. Að auki er aragrúi af hvatberum í frumunum, en þeir sjá um brennslu á brúnu fitunni með súrefni, sem skilar varma út í umhverfið.

Samkvæmt grein í tímaritinu Nature Cell Biology hefur bandarískum lífefnafræðingum við Stofnfrumustofnunina í Harvard nú tekizt að láta líkamann breyta ljósum fitufrumum í brúnar fitufrumur. Lengi hefur verið unnið að þessu verkefni á mörgum vígstöðum í þeirri von að finna töflur, sem stuðla að þessari breytingu. Þetta gæti þá gagnast þeim, sem eru of feitir, því að þá myndi verulegur hluti fitunnar brenna í sjálfum líkamanum án þess að fara á hlaupabretti.

Enn mun þó langt í land, að slíkar megrunarpillur verði til, en hver veit hvað framtíðin ber í skauti sér. Slíkri pillu fylgja þó ýmsir ókostir, því að líkamshiti mun hækka verulega og ljósa fitan er öllum nauðsynleg að vissu marki. Og sennilegast er talið, að fitubrennslupillur muni miklu frekar gagnast til þess að menn haldi réttri vikt fremur en til megrunar.

 

ÁHB / 9. desember 2014

 

Heimild: http://www.nature.com/ncb/journal/vaop/ncurrent/full/ncb3075.html

 


67 Responses to “Ljós fita verður að brúnni”
  1. Pyolzt says:

    provigil online – modafinil adhd order provigil online

  2. Lmspej says:

    how much is accutane – buy cheap accutane online cheap accutane singapore

  3. Pbihif says:

    buy amoxicillina noscript canada – amoxicilina 500 mg antibiotics without a doctor’s prescription

  4. Ipqpgd says:

    tania vardenafil generic – canadian pharmacy generic vardenafil vardenafil price

  5. Tvzuyx says:

    ivermectin covid – ivermectin cream canada cost ivermectin for humans walmart

  6. Nloyrb says:

    cialis 5mg online canada – buy cheap tadalafil uk 200 mg cialis

  7. Tfuajc says:

    ivermectine online – ivermectin tablets order stromectol tablets for humans for sale

  8. Jybfim says:

    lyrica capsules 25 mg – online pharmacy india online pharmacy india

  9. Oafked says:

    cialis online uk pharmacy – generic cialis online mastercard where to buy cialis over the counter in canada

  10. Yofoza says:

    buy ivermectin stromectol – ivermectin for covid ivermectin 6mg online

  11. Afjkaf says:

    3000mg prednisone – prednisone 59 mg buy prednisone 10mg

  12. Emiivr says:

    modafinil generic – modafinil and birth control modafinil and alcohol

  13. Mkcpsb says:

    buy azithromycin 250mg online – generic zithromax over the counter buy generic zithromax 250mg

  14. Nxxvjo says:

    price of tadalafil 20mg – cialis online safe canadian pharmacy coupon

  15. Atjujx says:

    stromectol pill price – where to buy ivermectin cream ivermectin oral solution

  16. Vkqrpf says:

    real casinos online no deposit – casinoslotgam hard rock casino online

  17. Plazlc says:

    cheap erectile dysfunction pill – shark tank ed pill episode erectile dysfunction meds

  18. Jrgrme says:

    prednisone 20 mg tablet – over the counter prednisone no prescription prednisone online

  19. Ttdpsf says:

    cheap generic sildenafil – online viagra tablet canada where can i buy viagra in canada

  20. Nmojfk says:

    cheap tadalafil tablets – Buy cialis in usa can i buy cialis over the counter in mexico

  21. Ensklm says:

    stromectol generic name – stromectol ivermectin ivermectin 5

  22. Jgnixm says:

    medicine for erectile – help for ed medicine for impotence

  23. Shoiqy says:

    can i buy ventolin over the counter in usa – ventolin 90 ventolin for sale

  24. Uprszv says:

    cytotec 800 – where can i buy cytotec pills in south africa how much is cytotec tablet

  25. Hkscwq says:

    neurontin cost in canada – neurontinpl.com levothyroxine 150

  26. Qdszfo says:

    canadian viagra no prescription – where can you buy real viagra online

  27. Uewxzl says:

    vardenafil vs viagra – low cost generic vardenafil where to buy vardenafil in canada

  28. Bthzvx says:

    ivermectin 3mg tabs – ivermectin 3mg dosage ivermectin canada

  29. Vpifin says:

    prednisone cream rx – cheap deltasone how much is a prednisone prescription

  30. Wlmart says:

    buy amoxicilin online – buy amoxicillina noscript canada amoxicillin for sinus infection

  31. Fqaigd says:

    medrol coupon – methylprednisolone generic cost for lyrica

  32. Mverit says:

    help with essays – instant essay writer write research papers

  33. Wrtadu says:

    generic cialis no prescription – Cialis samples tadalafil discount coupon

  34. Daqnyr says:

    prednisone buy – prednisone no rx generic over the counter prednisone

  35. Kiciary says:

    physician wiki ivermectin for humans amazon ivermectin para que sirve la ivermectina ivermektin for mennesker

  36. Smluef says:

    lasix 40 mg for sale – lasix 500 mg tablet price lasix 80 mg

  37. Andybm says:

    order Albuterol – topventoli ventolin online

  38. mokdiedo says:

    Ljos fita ver?ur a? brunni z pack cost no insurance buy amoxicillin zithromax azithromycin tablets

  39. Abnobe says:

    Ljos fita ver?ur a? brunni ivermectin ivermectin for humans buy ivermectin dosaggio della compressa di ivermectina 3 mg

  40. Xyqtvq says:

    where can you get cytotec – where to get cytotec buy cytotec mexico

  41. Oxgqmu says:

    doxycycline capsule 100mg price – buy prednisolone online uk prednisolone 20mg uk

  42. Gcfvdp says:

    ivermectin 0.5% brand name – stromectol 3 mg tablets price stromectol medicine

  43. Ztbeij says:

    cost stromectol – stromectol 3 mg tablet cost of ivermectin

  44. Xbciqm says:

    sildenafil 100mg – canadian sildenafil sildenafil alternative

  45. Apxyae says:

    sildenafil vs tadalafil – tadalafil 20 buy tadalafil

  46. Bctudf says:

    accutane cream for sale – accutane 5 mg accutane online cheap

  47. Syttvz says:

    best essay writers online – help writing a paper for college buy term papers online

  48. Hdiuef says:

    oral stromectol cost – ivermectin stromectol ivermectin dosage

  49. Lxxiwr says:

    sildenafil tablets uk – Real cialis online can you buy cialis from canada

  50. Ckmuio says:

    comprar vardenafil – vardeed over the counter ed pills

  51. Csvuus says:

    plaquenil for lupus – purchase prednisone buy prednisone online without prescription

  52. Zjrtwh says:

    fildena 150 usa and uk – vidalista 20 cenforce 100 mg online

  53. Ohhxiy says:

    xenical 120mg – orlistat medication side effects orlistat cancer

  54. Qhaxem says:

    ivermectin over counter – stromectol oral ivermectin 2mg

  55. Thigjg says:

    sildenafil otc us – sildenafil without a doctor’s prescription viagra tablets buy online in india

  56. Mfzctx says:

    how much does cialis cost – canadian pharmacy meds online pharmacy australia

  57. Smealf says:

    ivermectin tablets for sale walmart can humans take ivermectin paste ivermectin for humans for sale stromectol order online

  58. Kekowk says:

    deltasone 5 mg – prednisone cream prednisone 60 mg tablet

  59. Rudsbt says:

    ivermectin 15 mg – stromectol human stromectol pill

  60. Ksiggi says:

    order viagra mexico – viagra soft pills sale best prices sildenafil

  61. weilina says:

    ivermectin for humans stromectol gГ©nГ©rique ivermectin for humans amazon ivermectin 12 mg

Leave a Reply