scholarly journals Short-Term Administration of Supraphysiological Recombinant Human Growth Hormone (GH) Does Not Increase Maximum Endurance Exercise Capacity in Healthy, Active Young Men and Women with Normal GH-Insulin-Like Growth Factor I Axes

2005 ◽  
Vol 90 (6) ◽  
pp. 3268-3273 ◽  
Author(s):  
Annika Berggren ◽  
Christer Ehrnborg ◽  
Thord Rosén ◽  
Lars Ellegård ◽  
Bengt-Åke Bengtsson ◽  
...  

Context: Despite the fact that the use of GH as a doping agent in sports is widespread, little is known about its short-term effects. Objective: The objective was to study the effects of GH on exercise capacity. Design: A double-blind, placebo-controlled study was used, with a treatment period of 28 d. Setting: Subjects from general community studied ambulatory at a university hospital. Participants: Thirty healthy active young normal volunteers (15 women and 15 men) were recruited by local announcement, and all completed the study. Intervention: All subjects were randomized to receive a low GH dose (0.033 mg/kg·d or 0.1 IU/kg·d), a high GH dose (0.067 mg/kg·d or 0.2 IU/kg·d), or placebo. Main outcome measures: Power output and oxygen uptake on bicycle exercise were the main outcome measures. Results: We found no effect of the low or high dosages of GH on maximum oxygen uptake during exercise (mean ± se for placebo, 45.2 ± 1.6 to 45.2 ± 2.1 ml/kg·min; GH low dose, 42.8 ± 1.6 to 42.8 ± 1.6 ml/kg·min; GH high dose, 44.8 ± 3.4 to 44.8 ± 2.2 ml/kg·min; not significant by two-way ANOVA). Neither was there any effect on maximum achieved power output during exercise or on blood pressure, heart rate, or the electrocardiographic ST level at rest or during exercise. GH significantly increased total body weight (P = 0.028), an effect predominantly ascribed to fluid retention (increased extracellular water volume), whereas muscle mass (as indicated by intracellular water volume) did not change. However, changes in the latter correlated to changes in physical performance, possibly due to different training efforts. Conclusion: Administration of supraphysiological recombinant human GH during a period of 4 wk does not improve power output or oxygen uptake.

2017 ◽  
Vol 31 (10) ◽  
pp. 1374-1376
Author(s):  
Jack H Wilson ◽  
Amy H Criss ◽  
Sean A Spangler ◽  
Katherine Walukevich ◽  
Sandra Hewett

Nonsteroidal anti-inflammatory drugs work by non-selectively inhibiting cyclooxygenase enzymes. Evidence indicates that metabolites of the cyclooxygenase pathway play a critical role in the process of learning and memory. We evaluated whether acute naproxen treatment impairs short-term working memory, episodic memory, or semantic memory in a young, healthy adult population. Participants received a single dose of placebo or naproxen (750 mg) in random order separated by 7–10 days. Two hours following administration, participants completed five memory tasks. The administration of acute high-dose naproxen had no effect on memory in healthy young adults.


1997 ◽  
Vol 92 (4) ◽  
pp. 361-365 ◽  
Author(s):  
Helen F. Galley ◽  
Judith Thornton ◽  
Peter D. Howdle ◽  
Barry E. Walker ◽  
Nigel R Webster

1. Hypertension affects 30% of adults and low intakes of antioxidants have been associated with increased risk of hypertension and cardiovascular disease. To investigate the effect of short-term high-dose antioxidant supplementation on blood pressure in hypertensive and normotensive outpatients, we undertook a randomized, double-blind, crossover design placebo-controlled study. 2. Forty subjects were recruited from medical outpatient clinics, of whom 38 completed the study. Twenty-one were attending for treatment of hypertension and 17 were normotensive, attending for minor gastrointestinal complaints. Subjects were randomly assigned to receive either 8 weeks placebo followed by 2 weeks washout then 8 weeks antioxidants or vice versa. The combination of antioxidants consisted of 200 mg of zinc sulphate, 500 mg of ascorbic acid, 600 mg of α-tocopherol (sodium succinate salt) and 30 mg of β-carotene daily. 3. Systolic blood pressure fell at the end of the antioxidant phase compared with the placebo phase both in subjects receiving anti-hypertensive therapy (P < 0.01) and those who were normotensive (P = 0.067). Circulating levels of β-carotene and α-tocopherol increased in all subjects during supplementation (P < 0.01) and urine nitrite increased in hypertensive patients (P < 0.05). 4. Short-term oral high-dose combination antioxidant therapy reduces blood pressure, possibly via increased availability of nitric oxide. This study may have implications for the innovative use of antioxidants as an adjunct to anti-hypertensive therapy.


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