Testosterone and its role in muscle growth
Testosterone is the principal male sex hormone and classed as an anabolic steroid.
In guys, testosterone assumes a vital job in the advancement of the male reproductive tissues, for example, the testicles and prostate, as well as advancing secondary sexual attributes, for example, increased muscle and bone mass, and the development of body hair.
What’s more, testosterone is also associated with general wellbeing and prosperity and even has a counteractive action of osteoporosis.
Lacking levels of testosterone in men may prompt variations from the norm, including muscle loss and bone weakness.
See more information about testosterone and its role in muscle growth here.
The Effects Of Testosterone:
Anabolic steroids, such as testosterone, have two classes of effects, these are anabolic and androgenic.
Anabolic means to build up/create, androgenic means male attributes and characteristics.
Anabolic Effects:
- Growth of muscle mass
- Increased strength
- Improved bone density and strength
- Stimulation of linear growth (height)
- Bone maturation
Androgenic Effects:
- Maturation of sex organs
- Growth of facial hair
- Growth of body hair
- Deepening of the voice
- Promotion of other secondary sex characteristics
Production Of Testosterone:
It is synthesised in the body via several steps from cholesterol and is converted in the liver to its metabolites.
It exerts its action through binding to and activation of the androgen receptor.
In humans and most other vertebrates, testosterone is primarily secreted by the testes in males and, to a lesser extent, the ovaries in females.
Levels of testosterone in the average male are about 7-8 times as great as in females.
Because males metabolise testosterone faster than females, the daily production of testosterone is about 20 times as much compared to females.
Testosterone May Increase Muscle Cell Hypertrophy:
ERK1/2 and Akt showed an increase in phosphorylation after a testosterone stimulus at 5 minutes and 15 minutes, respectively.
S6K1 was phosphorylated at 60 minutes. This response was abolished by PI3K/Akt and mTOR inhibition but not by ERK1/2 inhibition.
CSA increased at 12 hours and was abolished by inhibitors of the PI3K/Akt pathway as well as by AR inhibition.
Testosterone May Increase GHRH & Growth Hormone:
Testosterone administration to boys increased mean spontaneous Growth Hormone secretion from 2.25mcg/L before testosterone administration to 6.77mcg/L after administration of testosterone.
However, it seems that the increase seen in Growth Hormone was mediated via an estrogenic pathway and therefore wasn’t directly the cause of testosterone.
Testosterone May Increase IGF-1:
Testosterone also significantly increases IGF-1.
Serum IGF-1 levels increased after 6 Weeks administration of Testosterone Enanthate (TE) at 300mg per week but did not change in the Nandrolone Decanoate (ND) group.
However, the level of major IGF-Binding Proteins was decreased in the ND group.
Testosterone May Decrease Myostatin:
Testosterone may have an impact on myostatin within skeletal muscle.
In one rat study assessing myostatin levels in the levator ani (LA) muscle of rats after castration, with the testosterone replacement, myostatin returned to baseline, and without testosterone replacement, active myostatin proteins were found to increase.
All of these factors combined leads to the conclusion that testosterone is a potent hormone and can lead to a heightened state of muscle growth if used in higher than average amounts.
However, the abuse of testosterone (and other androgens) can lead to some potentially dangerous side effects such as enlarged organs, especially the heart, high LDL and low HDL, and many more.