Nutrition 2002 Jul-Aug;18(7-8):657-61.
Comment in: Nutrition. 2002 Jul-Aug;18(7-8):683-4.
Use Of Amino Acids As Growth Hormone-Releasing Agents By Athletes.
Chromiak JA, Antonio J.
Department of Health, Physical Education, Recreation and Sport, Mississippi State University, PO Box 6186,
Mississippi State, MS 39762-6186, USA. jchrom@colled.msstate.edu
Specific amino acids, such as arginine, lysine and ornithine, can stimulate growth hormone (GH) release
when infused intravenously or administered orally. Many individuals consume amino acids before strength
training workouts, believing this practice accentuates the exercise-induced GH release, thereby promoting
greater gains in muscle mass and strength. The GH response to amino acid administration has a high degree of interindividual variability and may be altered by training status, sex, age, and diet. Although parenteral administration consistently leads to increased circulating GH concentration, oral doses that are great enough to induce significant GH release are likely to cause stomach discomfort and diarrhea. During exercise, intensity is a major determinant of GH release. Although one study showed that arginine infusion can heighten the GH response to exercise, no studies found that pre-exercise oral amino acid supplementation augments GH release. Further, no appropriately conducted scientific studies found that oral supplementation with amino acids, which are capable of inducing GH release, before strength training increases muscle mass and strength to a greater extent than strength training alone. The use of specific amino acids to stimulate GH release by athletes is not recommended.
PMID: 12093449 [PubMed - indexed for MEDLINE]
Curr Med Res Opin. 1981;7(7):475-81
A Study Of Growth Hormone Release In Man After Oral Administration Of Amino Acids.
Isidori A, Lo Monaco A, Cappa M.
A study was carried out in 15 male volunteers to evaluate qualitatively the secretion of growth factors
following stimulation by oral amino acids. The results showed that oral administration of a combination of
two amino acids (1200 mg 1-lysine plus 1200 mg 1-arginine) provoked a release of pituitary somatotropin
and insulin. This phenomenon was reproducible and the growth hormone secreted in response to this stimulation had biological activity (as demonstrated by a radioreceptor assay and somatomedin induction). The effect appeared to be specific to the combination of the two amino acids; neither of the amino acids demonstrated appreciable stimulating activity when administered alone, even at the same doses.
PMID: 6790230 [PubMed - indexed for MEDLINE]
Int J Sport Nutr. 1997 Mar;7(1):48-60.
Acute Effect Of Amino Acid Ingestion And Resistance Exercise On Plasma Growth Hormone Concentration In Young
Men.
Suminski RR, Robertson RJ, Goss FL, Arslanian S, Kang J, DaSilva S, Utter AC, Metz KF.
Human Performance Laboratory, University of Houston, TX 77204, USA.
Sixteen men completed four trials at random as follows: (Trial A) performance of a single bout of resistance
exercise preceded by placebo ingestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1,500 mg
L-lysine, immediately followed by exercise as in Trial A; (Trial C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30, 60, and 90 min during the exercise trials (A and B) compared with the resting trials (C and D) (p < .05). No differences were noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion compared with the placebo trial. It was concluded that ingestion of 1,500 mg arginine and 1,500 mg lysine immediately before resistance exercise does not alter exercise-induced changes in [GH] in young men. However, when the same amino acid mixture is ingested under basal conditions, the acute secretion of GH is increased.
PMID: 9063764 [PubMed - indexed for MEDLINE]
Artif Cells Blood Substit Immobil Biotechnol. 2003 Feb;31(1):35-46.
Human Osteopenic Bone-Derived Osteoblasts: Essential Amino Acids Treatment Effects.
Torricelli P, Fini M, Giavaresi G, Giardino R.
Experimental Surgery Department, Research Institute Codivilla-Putti, Rizzoli Orthopedic Institute, Bologna,
Italy. paola.torricelli@ior.it
The development of in vitro cell culture methods has made it possible to study bone cell metabolism and growth and obtain a deeper insight into the pathophysiology of common orthopedic diseases such as osteoporosis. After analyzing the effect of two essential amino acids, L-arginine (Arg) and L-lysine (Lys), in previous in vitro and in vivo studies, the present authors investigated the administration of Arg and Lys in osteoblasts derived from human osteopenic bone. After isolation, osteoblasts were cultured in DMEM supplemented with either Arg (0.625 mg/ml/day, Arg Group) or Lys (0.587 mg/ml/day, Lys Group), or both of them (Arg-Lys Group), whereas the Control Group was sham-treated. After 7 days the following parameters were tested in all groups: MTT proliferation test, Alkaline Phosphatase (ALP), Nitric Oxide (NO), Calcium (Ca), Phosphorus (P), Osteocalcin (OC), C-Terminal Procollagen type I (PICP), Interleukin-6 (IL-6), Transforming Growth Factor-beta 1 (TGF-beta 1), Platelet Derived Growth Factor (PDGF) and Insulin-Like Growth Factor-I (IGF-I). Results were compared with those obtained from human healthy bone
to verify the effect of the amino acids on osteoblasts derived from pathological tissue. In addition, a comparison was also made with the results obtained from rat osteopenic bone to assess reliability of the in vitro model. The current results support previous findings and indicate that Arg and Lys stimulation has a positive effect on osteoblast proliferation, activation and differentiation. Therefore, administration of these amino acids may be useful in clinical treatment and prevention of osteoporosis.
PMID: 12602815 [PubMed - indexed for MEDLINE]
