The fact is based on existing evidence whether GH actually stimulates protein synthesis is debatable. However currently available data is limited to relatively HIGH doses in growth retarded children and LOW dosing regimens in the elderly. Studies have also failed to reveal hypertrophic changes in younger athletes.
So what gives? Well I'm not sure but I do recall the AAS debate years ago where it was once believed anabolic agents do NOT enhance PS, lol!
I suspect the difference may lie in the fact GH users are not only pinning GH in the "high dose" range BUT the real distinction is their use of AAS and even perhaps insulin.
My point is secretagogues may be more beneficial than current evidence suggests especially for those mates with low GHRF levels and when combined with other PEDs, such as AAS .
Doctor S PLEASE add your opinion or any studies to elaborate further about GH and PS.
Regs
jim
J Physiol. 2010 Jan 15;588(Pt 2):341-51.
Growth hormone stimulates the collagen synthesis in human tendon and skeletal muscle without affecting myofibrillar protein synthesis.
Doessing S1,
Heinemeier KM,
Holm L,
Mackey AL,
Schjerling P,
Rennie M,
Smith K,
Reitelseder S,
Kappelgaard AM,
Rasmussen MH,
Flyvbjerg A,
Kjaer M.
Abstract
In skeletal muscle and tendon the extracellular matrix confers important tensile properties and is crucially important for tissue regeneration after injury. Musculoskeletal tissue adaptation is influenced by mechanical loading, which modulates the availability of growth factors, including growth hormone (GH) and insulin-like growth factor-I (IGF-I), which may be of key importance. To test the hypothesis that GH promotes matrix collagen synthesis in musculotendinous tissue, we investigated the effects of 14 day administration of 33-50 microg kg(-1) day(-1) recombinant human GH (rhGH) in healthy young individuals. rhGH administration caused an increase in serum GH, serum IGF-I, and IGF-I mRNA expression in tendon and muscle. Tendon collagen I mRNA expression and tendon collagen protein synthesis increased by 3.9-fold and 1.3-fold, respectively (P < 0.01 and P = 0.02), and muscle collagen I mRNA expression and muscle collagen protein synthesis increased by 2.3-fold and 5.8-fold, respectively (P < 0.01 and P = 0.06). Myofibrillar protein synthesis was unaffected by elevation of GH and IGF-I. Moderate exercise did not enhance the effects of GH manipulation. Thus, increased GH availability stimulates matrix collagen synthesis in skeletal muscle and tendon, but without any effect upon myofibrillar protein synthesis. The results suggest that GH is more important in strengthening the matrix tissue than for muscle cell hypertrophy in adult human musculotendinous tissue.
Open Access J Sports Med. 2011 Jul 27;2:99-111.
Growth hormone doping: a review.
Erotokritou-Mulligan I1,
Holt RI,
Sönksen PH.
Abstract
The use of growth hormone (GH) as a performance enhancing substance was first promoted in lay publications, long before scientists fully acknowledged its benefits. It is thought athletes currently use GH to enhance their athletic performance and to accelerate the healing of sporting injuries. Over recent years, a number of high profile athletes have admitted to using GH. To date, there is only limited and weak evidence for its beneficial effects on performance. Nevertheless the "hype" around its effectiveness and the lack of a foolproof detection methodology that will detect its abuse longer than 24 hours after the last injection has encouraged its widespread use. This article reviews the current evidence of the ergogenic effects of GH along with the risks associated with its use. The review also examines methodologies, both currently available and in development for detecting its abuse.
Horm Res. 2008;69(6):343-54.
Physical effects of short-term recombinant human growth hormone administration in abstinent steroid dependency.
Graham MR1,
Baker JS,
Evans P,
Kicman A,
Cowan D,
Hullin D,
Thomas N,
Davies B.
Erratum in
- Horm Res. 2008;70(2):128.
Abstract
BACKGROUND/AIMS:
Recombinant human growth hormone (rhGH) as opposed to cadaver pituitary GH is misused for physical improvement. Six days' rhGH administration, in abstinent anabolic-androgenic steroid dependents, was compared with controls.
METHOD:
Male subjects (n = 48) were randomly divided into two groups: (1): control group (C), n = 24, mean +/- SD, age 32 +/- 11 years, height 1.8 +/- 0.06 m; (2): rhGH-using group (0.058 IU.kg(-1).day(-1)) (GH), n = 24, mean +/- SD, age 32 +/- 9 years, height 1.8 +/- 0.07 m. Physiological measurements included anthropometry, strength, power and peak oxygen uptake (VO(2) peak). Biochemical measurements included haemoglobin, packed cell volume, glucose, sodium, potassium, urea, creatinine, total protein, albumin, thyroid function, testosterone, prolactin, cortisol, GH and insulin-like growth factor-I (IGF-I).
RESULTS:
Strength, peak power output and IGF-I significantly increased and total protein, albumin and free tetra-iodothyronine significantly decreased compared to controls (p < 0.05) and within the GH group (p < 0.017). Fat-free mass index and VO(2) peak significantly increased, while body fat and thyroid-stimulating hormone significantly decreased within the GH group (p < 0.017).
CONCLUSIONS:
Short-term rhGH increased strength and power. Of therapeutic value is the possibility that muscle bulk and strength could be increased in patients with muscle-wasting conditions.
Ann Intern Med. 2010 May 4;152(9):568-77.
The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial.
Meinhardt U1,
Nelson AE,
Hansen JL,
Birzniece V,
Clifford D,
Leung KC,
Graham K,
Ho KK.
Abstract
BACKGROUND:
Growth hormone is widely abused by athletes, frequently with androgenic steroids. Its effects on performance are unclear.
OBJECTIVE:
To determine the effect of growth hormone alone or with testosterone on body composition and measures of performance.
DESIGN:
Randomized, placebo-controlled, blinded study of 8 weeks of treatment followed by a 6-week washout period. Randomization was computer-generated with concealed allocation. (Australian-New Zealand Clinical Trials Registry registration number: ACTRN012605000508673)
SETTING:
Clinical research facility in Sydney, Australia.
PARTICIPANTS:
96 recreationally trained athletes (63 men and 33 women) with a mean age of 27.9 years (SD, 5.7).
INTERVENTION:
Men were randomly assigned to receive placebo, growth hormone (2 mg/d subcutaneously), testosterone (250 mg/wk intramuscularly), or combined treatments. Women were randomly assigned to receive either placebo or growth hormone (2 mg/d).
MEASUREMENTS:
Body composition variables (fat mass, lean body mass, extracellular water mass, and body cell mass) and physical performance variables (endurance [maximum oxygen consumption], strength [dead lift], power [jump height], and sprint capacity [Wingate value]).
RESULTS:
Body cell mass was correlated with all measures of performance at baseline. Growth hormone significantly reduced fat mass, increased lean body mass through an increase in extracellular water, and increased body cell mass in men when coadministered with testosterone. Growth hormone significantly increased sprint capacity, by 0.71 kJ (95% CI, 0.1 to 1.3 kJ; relative increase, 3.9% [CI, 0.0% to 7.7%]) in men and women combined and by 1.7 kJ (CI, 0.5 to 3.0 kJ; relative increase, 8.3% [CI, 3.0% to 13.6%]) when coadministered with testosterone to men; other performance measures did not significantly change. The increase in sprint capacity was not maintained 6 weeks after discontinuation of the drug.
LIMITATIONS:
Growth hormone dosage may have been lower than that used covertly by competitive athletes. The athletic significance of the observed improvements in sprint capacity is unclear, and the study was too small to draw conclusions about safety.
CONCLUSION:
Growth hormone supplementation influenced body composition and increased sprint capacity when administered alone and in combination with testosterone.
J Clin Endocrinol Metab. 2009 Jan;94(1):130-7.
Effects of recombinant human growth hormone therapy in obesity in adults: a meta analysis.
Mekala KC1,
Tritos NA.
Abstract
OBJECTIVE:
To conduct a metaanalysis of human studies examining the efficacy and safety of recombinant human GH (rhGH) as therapy for obesity in adults.
DESIGN:
A thorough search of the literature (including MEDLINE, EMBASE, and the Cochrane Register) was performed for pertinent studies, which were analyzed and subsequently synthesized in a comprehensive metaanalysis.
RESULTS:
Administration of rhGH led to significant changes in body composition [weighted mean difference (95% confidence interval)], including fat mass [-0.9 kg (-1.3 to -0.4)], percent body fat [-1% (-1.3 to -0.7)], lean body mass [1.8 kg (0.6-2.9)], visceral adipose area [-22.8 cm(2) (-39.8 to -5.7)], and lipid profile, including total cholesterol [-7 mg/dl (-11 to -3)] and low-density lipoprotein-cholesterol [-9 mg/dl (-13 to -5)]. There were increases in fasting plasma glucose [3 mg/dl (1-6)] and insulin [1.9 muU/ml (0.2-3.7)]. The latter finding was found only in shorter-term studies. Adverse effects included [odds ratio (95% confidence interval)] arthralgias [6 (1.9-18.6)], peripheral edema [5 (2.4-10.5)], and paresthesias [6.5 (1.5-27.3)].
CONCLUSIONS:
Our metaanalysis suggests that rhGH therapy leads to decrease in visceral adiposity and increase in lean body mass as well as beneficial changes in lipid profile in obese adults, without inducing weight loss. Administration of rhGH was associated with increases in fasting plasma glucose and insulinemia. Because the rhGH doses used in many studies were supraphysiological, future studies of longer duration, using carefully titrated rhGH protocols, will be needed to fully establish the effects of rhGH therapy in obesity, including effects on cardiovascular morbidity and mortality.
