Tuesday, May 10, 2011

Resveratrol For Fat Loss: Scientists Uncover Underlying Mechanism - Increase in ATGL Gene and Protein Expression

Maybe you have been wondering that I am posting relatively little information about the stilbenoid resveratrol. And you may also be surprised to hear that this is not despite, but rather because the grape polyphenol is among the current favorites of each and every lab-coated petri-dish attendant, who either has or is just in the process of obtaining his PhD. There is a massive amount of rather useless studies on its in vitro effects on dubious cancer cells and a whole bunch of other data without practical relevance published day by day. Studies such as the one Lasa et al. (Lasa. 2011), which actually contribute to our understanding of how resveratrol actually works, on the other hand, are scarce.
Figure 1: Increases in hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) mRNA levels (=gene activity) in two different human adipocyte cell lines (SGBS vs. 3T3-L1); data adapted from Lasa. 2011
In their study, which is going to be published in the Journal of Nutritional Medicine, the scientist describe an experiment designed to explore the underlying mechanisms of resveratrol's "fat burning", i.e. lipolytic (release NOT oxidation of fats), effects. Lasa et al. used both human adipocytes, as well as, mouse adipocytes from adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL)-knockout mice, incubated them with resveratrol at 100 μM for 12, 24, and 48h and found:
Resveratrol-induced free fatty acids release but not glycerol release in 3T3-L1 under basal and isoproterenol-stimulating conditions and under isoproterenol-stimulating [isoproterenol is a Isoprenaline is a β1- and β2-adrenoceptor agonist similar to nor-adrenaline] conditions in [human] adipocytes.
Meaning that resveratrol stimulates lipolysis both under normal, as well as under stressed (nor-adrenaline release condition mirrored by isoporterenol administration) conditions [remember you still have to oxidize the liberated fatty acids to get rid of the fat]. From the fact that "[w]hen HSL was blocked by compound 76-0079, free fatty acid release was still induced by resveratrol" and the observed increase in ATGL gene and protein expression, and the lack of effect on HSL by resveratrol, the scientists conclude that
Image 1: Resveratrol supplements are
readily available as OTC products
[...] the present results provide novel evidence that resveratrol regulates lipolytic activity in human and murine adipocytes, as well as in white adipose tissue from mice, acting mainly on ATGL at transcriptional and posttranscriptional levels. Enzyme activation seems to be induced via adenosine monophosphate-activated protein kinase [AMPK].
While this won't really change the partly conflicting and far from earth-shattering results of studies on the effectiveness of oral administration of resveratrol to human beings on obesity and fatty acid metabolism, it does at least show you that - assuming you reach adequate resveratrol levels at the receptor level by oral administration - resveratrol will help you liberate fat from adipose tissue. But don't forget: It is yet still up to you to get moving / fasting to burn these fatty acids and thus to prevent them from settling just back into their comfortable "fat seats", when the lipase activity seizes.