Lyhyt yhteenveto arginiinista (pätkä omasta MD artikkelista). Ja samalla "julistan" MD Nutrition Performance & Supplement Performance "ideakilpailun"
; ehdota aihetta em. MD-osiohin. Jos ideasi menee käyttöön, niin nimesi ja osoitteesi laitetaan MD:n complimentary copy listalle eli ilmainen lehti napsahtaa kotiin niin kauan kuin firma on pystyssä (tulee tosin kakkospostina Jenkkilästä asti, joten tulee perille suht hitaasti...).
Arginine
Arginine is classified as a conditionally essential amino acid. Although it has numerous important physiological functions, gym rats have taken arginine supplements for two main reasons: 1) to increase growth hormone secretion; and 2) to augment nitric oxide (NO) synthesis. However, it’s now clear that oral arginine supplementation alone has little, if any, effect on growth hormone secretion. However, one study reported that the ingestion of arginine (1.5 grams) and lysine (1.5 grams) resulted in a 2.7-fold increase in growth hormone concentration in strength-trained athletes. So, the argine plus lysine combo appears to be a somewhat effective “GH booster.”
As noted above, another possible ergogenic potential of arginine is its role in the synthesis of nitric oxide (NO). NO acts as a signaling molecule to faciliate the dilation of blood vessels; its main effect on muscle metabolism is to increase the delivery and uptake of nutrients via its vasodilating effects. Recently, nitric oxide boosters (i.e., arginine, arginine alpha-ketoglutarate [AAKG]) have become popular among serious gym rats. It’s been suggested that these products enhance blood flow to muscle, in turn leading to greater gains in muscle mass and strength during training.
A recent study at the Baylor University´s Exercise & Sports Nutrition Lab examined the effects of AAKG supplementation during training on body composition and training adaptations in experienced gym rats. Thirty-five resistance-trained males were matched according to fat-free mass and randomly assigned to ingest supplements containing either a placebo (fake supplement) or commercial AAKG supplement in a double-blind manner (an experimental procedure in which neither the subjects nor the experimenters know which subjects are in the test and control groups during the actual course of the experiments).
Subjects took four grams of the supplements three times daily (12 grams per day) for eight weeks during standardized training. No significant differences were observed between groups in terms of changes in body mass, fat-free mass, fat mass, or percent body fat.
However, changes in bench press one repetition maximum were significantly greater in the AAKG group. It’s mystery how AAKG supplementation added an average of more than 13 pounds to bench press max over placebo without a concomitant increase in muscle mass. This seems to suggest that the changes are neural in origin.
In patients with stable angina pectoris (a disease marked by brief attacks of chest pain precipitated by deficient oxygenation of the heart muscles), ingestion of six grams of arginine per day for three days has been shown to improve exercise workload during a treadmill stress test. The vasodilatory properties of arginine may facilitate an increase in oxygen delivery, which helps meet the increased demands caused by exercise.
Finally, it has been reported that arginine treatment prevents the development of high blood pressure (hypertension) in animals prone to this disease and also causes rapid reduction in both systolic and diastolic blood pressures when infused into healthy humans and patients with essential hypertension (a common form of hypertension that occurs in the absence of any evident cause). So, it is possible that arginine supplementation may offer some protective effects in those athletes using drugs.
