scholarly journals Effects of a single dose of N-Acetyl-5-methoxytryptamine (Melatonin) and resistance exercise on the growth hormone/IGF-1 axis in young males and females

2007 ◽  
Vol 4 (1) ◽  
pp. 14 ◽  
Author(s):  
Erika Nassar ◽  
Chris Mulligan ◽  
Lem Taylor ◽  
Chad Kerksick ◽  
Melyn Galbreath ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Single Dose ◽  
Resistance Exercise ◽  
Young Males ◽  
Males And Females

433 THE EFFECT OF AMINO ACID INGESTION AND RESISTANCE EXERCISE ON GROWTH HORMONE RESPONSES IN YOUNG MALES

1993 ◽  
Vol 25 (Supplement) ◽  
pp. S77 ◽  
Author(s):  
R. R. Suminski ◽  
R. J. Robertson ◽  
F. L. Goss ◽  
A. G. Robinson ◽  
S. G. DaSilva ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Young Males ◽  
Hormone Responses

Satellite cell and myonuclear accretion is related to training-induced skeletal muscle fiber hypertrophy in young males and females

2021 ◽  
Author(s):  
Sidney Abou Sawan ◽  
Nathan Hodson ◽  
Paul Babits ◽  
Julia M. Malowany ◽  
Dinesh A. Kumbhare ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Whole Body ◽  
Type I ◽  
Type Ii ◽  
Young Males ◽  
Males And Females ◽  
Type Ii Fibers

Satellite cells (SC) play an integral role in the recovery from skeletal muscle damage and supporting muscle hypertrophy. Acute resistance exercise typically elevates type I and type II SC content 24-96 hours post-exercise in healthy young males, although comparable research in females is lacking. We aimed to elucidate whether sex-based differences exist in fiber type-specific SC content after resistance exercise in the untrained (UT) and trained (T) states. Ten young males (23.0 ± 4.0y) and females (23.0 ± 4.8y) completed an acute bout of resistance exercise before and after 8 weeks of whole-body resistance training. Muscle biopsies were taken from the vastus lateralis immediately prior to and 24 and 48-hours after each bout to determine SC and myonuclear content by immunohistochemistry. Males had greater SC associated with type II fibers (P ≤ 0.03). There was no effect of acute resistance exercise on SC content in either fiber type (P ≥ 0.58) for either sex, however, training increased SC in type II fibers (P < 0.01) irrespective of sex. The change in mean 0-48 h type II SC was positively correlated with muscle fiber hypertrophy in type II fibers (r = 0.47; P = 0.035). Furthermore, the change in myonuclei per fiber was positively correlated with type I and type II fiber hypertrophy (both r = 0.68; P < 0.01). Our results suggest that SC responses to acute and chronic resistance exercise are similar in males and females and that SC and myonuclear accretion is related to training-induced muscle fiber hypertrophy.

The Acute Effects of Androstenedione Supplementation in Healthy Young Males

2000 ◽  
Vol 25 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Craig S. Ballantyne ◽  
Stuart M. Phillips ◽  
Jay R. Macdonald ◽  
Mark A. Tarnopolsky ◽  
J. Duncan Macdougall
Keyword(s):  
Luteinizing Hormone ◽  
Resistance Exercise ◽  
Elevated Plasma ◽  
Acute Effects ◽  
Double Blind ◽  
Male Athletes ◽  
Young Males ◽  
Plasma Estradiol ◽  
Key Words Testosterone ◽  
Heavy Resistance Exercise

We examined the effects of androstenedione supplementation on the hormonal profile of 10 males and its interaction with resistance exercise. Baseline testosterone, luteinizing hormone, estradiol, and androstenedione concentrations were established by venous sampling at 3 hr intervals over 24 hr. Subjects ingested 200 mg of androstenedione daily for 2 days, with second and third day blood samples. Two weeks later, they ingested androstenedione or a placebo for 2 days, in a double-blind, cross-over design. On day 2, they performed heavy resistance exercise with blood sampled before, after, and 90 min post. The supplement elevated plasma androstenedione 2-3-fold and luteinizing hormone ∼70% but did not alter testosterone concentration. Exercise elevated testosterone, with no difference between conditions. Exercise in the supplemented condition significantly elevated plasma estradiol by ∼83% for 90 min. Androstenedione supplementation, thus, is unlikely to provide male athletes with any anabolic benefit and, with heavy resistance exercise, elevates estrogen. Key Words: testosterone, luteinizing hormone, estradiol, fluid shifts, resistance exercise

Dispersal patterns in a regional koala population in south-east Queensland

2003 ◽  
Vol 30 (3) ◽  
pp. 281 ◽  
Author(s):  
David S. Dique ◽  
Jim Thompson ◽  
Harriet J. Preece ◽  
Deidré L. de Villiers ◽  
Frank N. Carrick
Keyword(s):  
Urban Areas ◽  
Home Ranges ◽  
Adult Males ◽  
Dispersal Patterns ◽  
Young Males ◽  
Straight Line ◽  
The Social ◽  
Straight Line Distance ◽  
Males And Females ◽  
Natal Home

Koala dispersal was investigated as part of a detailed ecological study of a nationally significant koala population located 20 km south-east of Brisbane, Queensland. From 1996 to 2000, 195 koalas from three sites were captured and fitted with radio-collars. A total of 40 koalas (23 males and 17 females) dispersed from these sites. Most (93%) dispersing individuals were 20–36 months of age. Three adult females (more than 36 months old) dispersed and no adult males dispersed during the study. A significantly higher proportion of young males dispersed than females. Dispersal occurred between June and December, with most dispersal of males commencing in July and August and that of females commencing between September and November prior to, and early in, the annual breeding season. The mean straight-line distance between the natal and breeding home ranges for males and females was similar and was measured at 3.5 km (range 1.1–9.7 km) and 3.4 km (range 0.3–10.6 km) respectively. Dispersing males and females tended to successfully disperse south and west of their natal home ranges and were generally unable to successfully disperse to urban areas within the study area, as a high proportion of the mortality of dispersing koalas was associated with attacks by domestic dogs and with collisions with vehicles on roads. Information from other studies indicates that most young koalas disperse from their natal areas. It is likely that the social behaviour and mating systems of koala populations provide mechanisms for young koalas to disperse. The potential role of dispersal in the dynamics of regional koala populations is discussed.

Resistance exercise and growth hormone as countermeasures for skeletal muscle atrophy in hindlimb-suspended rats

1994 ◽  
Vol 267 (2) ◽  
pp. R365-R371 ◽  
Author(s):  
J. K. Linderman ◽  
K. L. Gosselink ◽  
F. W. Booth ◽  
V. R. Mukku ◽  
R. E. Grindeland
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Resistance Exercise ◽  
Protein Content ◽  
Muscle Atrophy ◽  
Myofibrillar Protein ◽  
Hindlimb Suspension ◽  
Skeletal Muscle Atrophy ◽  
Plantar Flexor ◽  
Fast Twitch

Unweighting of rat hindlimb muscles results in skeletal muscle atrophy, decreased protein synthesis, and reduced growth hormone (GH) secretion. Resistance exercise (ladder climbing) and GH treatment partially attenuate skeletal muscle atrophy in hypophysectomized hindlimb-suspended rats. It was hypothesized that a combination of multiple bouts of daily resistance exercise and GH (1 mg.kg-1.day-1) would prevent skeletal muscle atrophy in growing nonhypophysectomized hindlimb-suspended rats. Hindlimb suspension decreased the absolute (mg/pair) and relative (mg/100 g body wt) weights of the soleus, a slow-twitch plantar flexor, by 30 and 21%, respectively, and the absolute and relative weights of the gastrocnemius, a predominantly fast-twitch plantar flexor, by 20 and 11%, respectively (P < 0.05). Exercise did not increase soleus mass but attenuated loss of relative wet weight in the gastrocnemius muscles of hindlimb-suspended rats (P < 0.05). Hindlimb suspension decreased gastrocnemius myofibrillar protein content and synthesis (mg/day) by 26 and 64%, respectively (P < 0.05). The combination of exercise and GH attenuated loss of gastrocnemius myofibrillar protein content and synthesis by 70 and 23%, respectively (P < 0.05). Results of the present investigation indicate that a combination of GH and resistance exercise attenuates atrophy of unweighted fast-twitch skeletal muscles.

Systemic Effect of Human Growth Hormone after Intramuscular Injection of a Single Dose of a Muscle-Specific Gene Medicine

1998 ◽  
Vol 9 (5) ◽  
pp. 659-670 ◽  
Author(s):  
Khursheed Anwer ◽  
Mei Shi ◽  
Martha F. French ◽  
Susanne R. Muller ◽  
Wei Chen ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Single Dose ◽  
Human Growth Hormone ◽  
Intramuscular Injection ◽  
Human Growth ◽  
Systemic Effect ◽  
Specific Gene

Suicide and unemployment in young people

1999 ◽  
Vol 175 (3) ◽  
pp. 263-270 ◽  
Author(s):  
David Gunnell ◽  
Tom Lopatatzidis ◽  
Daniel Dorling ◽  
Helen Wehner ◽  
Humphrey Southall ◽  
...  
Keyword(s):  
Secular Trends ◽  
Young Males ◽  
Factors Associated ◽  
Economic Climate ◽  
Economic Recessions ◽  
Trend Data ◽  
Recession Rates ◽  
Unemployment Data ◽  
Males And Females ◽  
Old Men

BackgroundThe influence of the macro-economic climate on suicide is unclear. During the recent recession, rates have increased in young males but declined in females.AimsTo investigate associations between unemployment and suicide in 15 – to 44-year-old men and women over a period spanning two major economic recessions (1921–1995). To minimise confounding by changes in method availability, analyses are restricted to suicides using methods other than poisons and gases.MethodTime-series analysis using routine mortality and unemployment data.ResultsThere were significant associations between unemployment and suicide in both males and females. Associations were generally stronger at younger ages.ConclusionsSecular trends in youth suicide may be influenced by unemployment or other factors associated with changes in the macroeconomic climate. These factors appear to affect women to the same extent as men. Although it is not possible to draw firm aetiological conclusions from time-trend data, our findings are in keeping with those of person-based studies.

Transient impairment or delay of urinary trihydroxypregnanone (THS) response to metyrapone in boys with delayed adolescence and in patients with isolated growth hormone deficiency

1982 ◽  
Vol 99 (2) ◽  
pp. 166-173 ◽  
Author(s):  
M. Zachmann ◽  
D. Tassinari ◽  
W. Sorgo ◽  
G. U. Exner ◽  
B. Kempken ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Single Dose ◽  
Growth Hormone Deficiency ◽  
Bone Age ◽  
Urine Samples ◽  
Hormone Deficiency ◽  
Cortisol Response ◽  
Transient Impairment ◽  
Group A ◽  
Group B

Abstract. Twentythree boys with delayed adolescence (age 15.7 ± 2.0, bone age 12.4 ± 2.1 years) were studied. Their cortisol response to insulin was normal. After oral metyrapone (500 mg/m2 by mouth) one to three consecutive 12 h urine samples were collected for analysis of THS. Thirtyseven tests with 37 first, 21 second, and 11 third samples were carried out. The results could be divided into two main groups: 25 tests (group A) were subnormal in the first sample, 12 of them with a very weak (40 ± 8 μg/m2/12 h) and 13 with an insufficient (191 ± 16 μg/m2/12 h) THS response. Values in the second and third sample were higher, indicating a dealyed response. In 12 tests (group B), the results were normal (1016 ± 143 μg/m2/12 h) in the first and lower in the second and third samples. In three patients with repeated tests, there was improvement with increasing bone age. The THS-responses to metyrapone did not correlate with those of growth hormone, gonadotrophins, and TSH to stimuli. It is concluded that the THS-response to a single dose of metyrapone may be temporarily insufficient or delayed in delayed adolescence. We interpret this finding as showing transiently reduced or slow hypothalamic responsiveness.

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