Welcome to ProSource.net! »
SIGN-UP FOR EMAILS
FREE SHIPPING OVER $200!*
*Everyday Flat Rate Shipping $5.95
New Product Showcase
ProSource Brand Products
ProSource Gift Cards
Top 50 Products
Research & Development
Featured Athlete Profiles
ProSource Advisory Board
Free Supplement Encyclopedia
Free VIP E-mails
Deals & Coupons
Deal of the Day
Deal of the Month
Coupons and Promos
Connect with Us
Call Us at 1-800-310-1555
Help and Customer Support
4 Dimension Nutrition
AI Sports Nutrition
All American EFX
Alpha Pro Nutrition
American Body Building
Arnold Schwarzenegger Series
Athletic Edge Nutrition
Barn Dad Nutrition
Beast Sports Nutrition
Chef Jay's Foods
CON-CRET Promera Health
German American Tech / GAT
Gunnar Peterson System
Hair No More
Health From the Sun
Healthy N Fit
Isatori Global Tech
Lenny & Larry's
Millennium Sport Technologies
MuscleTech Essential Series
New Whey Nutrition
NRG X Labs
Nuts 'N More
PES Physique Enhancing Science
Ronnie Coleman Signature Series
Serious Nutrition Solutions / SNS
Six Star Pro Nutrition
Supreme Protein Inc
Swole Sports Nutrition
Top Secret Nutrition
Books and DVDs
Branch Chain Aminos
Energy and Endurance
Equipment & Apparel
Especially For Men
Especially For Women
Growth Support Formulas
Health and Wellness
Mass and Strength Builders
Multi-Vitamins & Minerals
New Product Showcase
Post-Workout / Muscle Recovery
Protein & Energy Bars
RTD (Ready to Drink) Formulas
All supplement brands listed A-Z
Products listed by product type.
Top Rated Products
Best in Class
Top products that hold the coveted "Best in Class" awards
Top 50 Supplements
ProSource.net's top selling products
Exclusive Deals and Sales
Deal of the Day
Every day a single top-brand supplement is featured at extreme savings.
Deal of the Month
Each month a single top-brand product is featured at extreme savings.
Coupon codes and sale items, up to an additional 60% off already low prices!
FREE SUPPLEMENT CATALOG HERE >>
Articles by ProSource
By Chad Kerksick, PhD | Jul 25, 2012
Leucine, Essential Amino Acids
and the mTOR Muscle Growth Pathway
Do you know what nutrients are best consumed in combination with your regular workouts? A great many people consume increased amounts of protein because they know when combined with a consistent heavy resistance training program it can help facilitate greater adaptations to their training. These desired adaptations are often
and lean muscle tissue as well as improvements in body composition. Another topic commonly discussed of late has been nutrient timing. Do you know when you should be consuming these nutrients? A number of published scientific articles and recent articles on the ProSource website have addressed this topic and this is an area that many sports nutrition researchers are working hard to better understand.
How many of you know why you should consume these nutrients? I'm not just talking about, "Because they increase muscle growth!" How many of you know what factors have been shown in scientific studies to be influenced inside your body as a result of taking nutrients like
? This article will outline the key aspects of
which are thought to actually occur insider your muscles' cells.
For starters, a number of factors must be in place to stimulate positive changes in muscle growth and body composition. The overall power and influence of a consistent, sound resistance training program cannot be understated. If you aren't regularly hitting the gym, using intensity levels that challenge your muscles and selecting exercises that use a large amount of muscle,
positive improvements in muscle mass
and body composition will likely be difficult to achieve.
Follow us on
for a chance to win this product!
Muscle growth and amino acids
Other key factors include getting enough calories in your diet and getting optimal amounts of
key amino acids
. Consuming the right amount of calories day in and day out is critical to help stimulate favorable body composition changes and a full discussion is beyond the purpose of this article. Cutting calories too much even with an intense resistance training program can create too much of an energy shortage that leaves your body starving for nutrients to fuel all of the internal processes needed on a daily basis. Overeating, on the other hand, supplies enough calories for muscle growth, but also results in fat growth; not the outcome you were hoping to achieve.
That leaves the intake of key proteins and amino acids which have been shown to stimulate
increases in lean tissue, strength
and other favorable adaptations. The best protein sources for muscle growth and recovery provide the greatest amounts of the essential amino acids (Phillips 2009); those shown by research to be exclusively required for muscle growth (Tipton 1999; Volpi 2003). For no other reason, this is why protein products which contain whey protein isolate such as ProSource's NytroWhey Ultra Elite are invaluable. But why?
The mTOR pathway to anabolism
A number of components inside muscle cells have been discussed, but no other molecule has been discussed as much as mTOR, which stands for the mammalian target of rapamycin. Scientists have identified mTOR as a central nexus for cellular growth. A better picture to get in your head is that of the hub of a wheel with a number of spokes coming from the hub. The spokes represent the many different factors which can increase or decrease the activity of mTOR, which in the end will all go on to impact the extent to which the cell in question grows. Remember in this case we are most concerned with the growth of muscle cells.
Interestingly, a number of factors have been suggested to impact the activity of mTOR and these factors are commonly referred to as "upstream" factors. Two "downstream" factors or those factors which are impacted as a direct result of mTOR activity, however, have dominated the scientific literature. These two factors are called p70s6k and 4E-BP1. Come again? p70 what? 4E-BP who? Did you just sneeze while typing on the keyboard? I realize it seems like alphabet soup and candidly a definition of the letters and numbers isn't important. Remember this! The first factor, p70s6k, helps to increase the production of key molecules called ribosomes which are "make or break" molecules in the process of building new muscle proteins. 4E-BP1 is closely involved in the process called translation where a complex code of molecules is translated resulting in the building of proteins. When activated by mTOR, 4E-BP1 helps to initiate or begin the translation process, which contributes to the growth of new proteins. Certainly, a number of other factors can be discussed resulting in a growing array of arrows being drawn to and from mTOR, but that would be overkill. In summary, high quality dietary proteins like whey, casein, egg and other animal proteins contain high amounts of the essential amino acids which research has shown to stimulate positive changes in mTOR which then goes on to positively impact two key factors, p70s6k and 4E-BP1, leading to increases in muscle protein growth.
For reasons scientists have yet to fully understand, the essential amino acid,
has been shown to play a critical role in the process of muscle growth. For example, a number of very detailed and specific studies involving just muscle cells and laboratory animals continually suggest that the mere presence and the overall amount of leucine can impact the extent to which anabolic process in muscles are impacted (Garlick 2005). For example, when sixteen healthy male subjects consumed either no drink or a leucine-enriched drink containing carbohydrates and other amino acids one hour after completing a bout of resistance training, rates of muscle protein synthesis were increased to a greater extent after the leucine containing drink. Moreover, when the researchers specifically examined the expression of key proteins such as mTOR, p70s6k and 4E-BP1, all of these key molecules were expressed to a greater extent after consumption of the leucine containing drink (Dreyer 2008). Additionally, a recent scientific review of articles devoted specifically to the impact of resistance exercise and nutrients (with particular emphasis on leucine-enriched solutions of the essential amino acids) was published (Drummond 2009). In this review, the authors reported that both resistance exercise and nutrients alone or in combination can stimulate positive changes in muscle protein growth as well as the activity of mTOR and signaling to its downstream targets (e.g. p70s6k and 4E-BP1). In highlighting the available research, the authors concluded that the mTOR communication pathway within muscle cells is a key and central pathway which controls rates of muscle protein growth. Furthermore, the authors recommended that essential amino acid ingestion occur shortly following a bout of resistance exercise to promote muscle protein growth (Drummond 2009).
The importance of protein intake, and specifically leucine and essential amino acid intake, cannot be overstated. In this respect, a recent study had eight healthy adults cycle for 60 minutes at 60% of their capacity and consume a drink which contained either 1.87 or 3.5 grams of leucine. Regardless of leucine content, both drinks contained a total ten grams of the essential
, which would be similar to around 20 grams of a whey protein isolate. In recovery from the exercise bout, rates of muscle protein synthesis were higher when greater amounts of leucine were ingested (Pasiakos 2011).
In closing, optimal protein intake and specifically the intake of the essential amino acids and in particular leucine continue to be shown in research to be a critically important first step in promoting an environment inside your muscles where they can grow. While various protein sources exist, whey protein isolates regularly contain the highest amounts of these important nutrients. Among whey products, it's hard to do better than the ProSource's own NytroWhey Ultra Elite, which contains an elite-quality, growth-factor-rich CFM whey isolate combined with a premium, ultra-rapid action super whey hydrolysate (WPH) and Leuvonâ„¢ 590, a highly bioavailable Leucine- Bound Leucine Peptide with a remarkable capacity to help switch on anabolism. Certainly, NytroWhey Ultra Elite contains impressive amounts of the essential amino acids, including up to four times the leucine content of competing protein formulations.
In this respect, regularly supplementing your diet with supplements like NytroWhey Ultra Elite within an hour after each workout can help you take advantage of not only key nutrient timing considerations but also the latest scientific research which shows that the combination of physical exercise and essential amino acid availability can maximize your body's ability to grow bigger and better muscles.
Dreyer, H. C., M. J. Drummond, et al. "Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle." American journal of physiology Endocrinology and metabolism (2008) 294(2): E392-400.
Drummond, M. J., H. C. Dreyer, et al. "Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling." J Appl Physiol (2009) 106(4): 1374-1384.
Garlick, P. J. "The role of leucine in the regulation of protein metabolism." J Nutr (2005) 135(6 Suppl): 1553S-1556S.
Pasiakos, S. M., H. L. McClung, et al. "Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis." The American journal of clinical nutrition (2011) 94(3): 809-818.
Phillips, S. M., J. E. Tang, et al. "The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons." Journal of the American College of Nutrition (2009) 28(4): 343-354.
Tipton, K. D., B. E. Gurkin, et al. "Nonessential amino acids are not necessary to stimulate net muscle protein synthesis in healthy volunteers." J Nutr Biochem (1999) 10(2): 89-95.
Volpi, E., H. Kobayashi, et al. "Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults." Am J Clin Nutr (2003) 78(2): 250-258.
Other Articles You May Be Interested In
Is Protein Thermogenic?
Why NytroWhey Ultra Elite Really Can Supercharge Your Gains
LEAVE A COMMENT
The articles featured herein are for informational purposes only and should not be construed as medical advice. Specific medical advice should only be obtained from a licensed health care professional. No liability is assumed by ProSource for any information herein.
Return to Top
Report Site Errors
Click Here for Important Safety Information
More Ways to Score Deals & Discounts
FREE Catalog by Mail
FREE Catalog Online
Sign Up for VIP E-mails
Find us on Facebook
Follow us on Twitter
Terms & Conditions
New Product Showcase
Order Tracking & Order History
Ask the Experts
Best Discounted Bodybuilding and Nutritional Supplements!
Hot Muscle Building Supplements
BSN NO Xplode
Hot Fat Loss Supplements
100% Whey Gold Standard
Nutrex Lipo 6
Supplement Discounts & Coupons
Gaspari Superpump MAX
CytoSport Muscle Milk
Hot Selling Brands
ProSource.net - Lowest Price Bodybuilding and Nutrition Supplements!
ProSource, 2231 Landmark Place, Manasquan, NJ 08736
Contact Customer Service