What is Testosterone?

Testosterone secretion in males follows a circadian rhythm, with a peak at 7-9 am and trough in late afternoon. Testosterone is a sex hormone that plays important roles in the body. In men, it’s thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm.

Actions of Testosterone

The features of pubarche in puberty, growth of pubic hair, typically but not exclusively at the beginning of puberty. Anabolism, typically defined as an increased metabolism in order to synthesise macromolecules. Maintenance of gametogenesis; in males this is the final maturation of spermatids to spermatozoa requires the action of testosterone on the Sertoli cells. Negative feedback on secretion of luteinizing hormone (LH) by the pituitary glands

Transport

Hypogonadotrophic hypogonadism is a disorder where the ovaries (in females) or the testes (in males) are not signalled to generate sex hormones by hormones produced by the brain or pituitary gland.

Above all, a big influence on testosterone levels are taking certain medications, including:

• Anabolic steroids
• Opiates
• Glucocorticoids-steroids

When looking to measure testosterone levels it is also wise to measure the following markers:

1. Prolactin.

• The body’s secretion of gonadotropin-releasing hormone (GnRH) may be impacted by prolactin. Lower amounts of LH may result from this, which would then reduce the synthesis of testosterone.

2. Iron levels.

• Iron decreases LH and testosterone levels. Conversely, testosterone regulates body iron levels by inhibiting hepcidin synthesis.

3. Liver function

• Men with fatty liver had lower total testosterone levels and SHBG levels and higher DHEA and E2 levels regardless of patient factors such as age and ethnicity.

4. Kidney function.

• Renal failure is associated with decreased luteinizing hormone (LH) production, reducing the synthesis of testosterone (see above)

Furthermore, consider pituitary Imaging- if other symptoms co-exist.

Another influencing factor on testosterone readings include your own medical history and your family history. Make note of the following:

• Diabetes.Type 2.
• Coeliac Disease
• Inflammatory bowel diseases.
• Other chronic diseases.
• Active/undiagnosed Breast or prostate cancer
• A palpable prostate nodule on per rectal exam or induration without further urological evaluation

Some markers that are useful to measure include: PSA >4 ng/mL (or >3 ng/mL in men at high risk of prostate cancer) without further urological evaluation.

Severe lower urinary tract symptoms (International prostate symptom score >19) Blood Haematocrit >50%

If you are looking to supplement your hormones with Testosterone Replacement Therapy (TRT) you should avoid so if you have untreated severe obstructive sleep apnoea and uncontrolled or poorly controlled heart failure when fertility is desired.

Conclusion

To sum up, testosterone is an essential sex hormone that controls many physiological functions in the male body, including desire, bone density, fat distribution, muscle mass and strength, and the generation of sperm and red blood cells. Its secretion has a circadian rhythm, with an early morning peak and a late afternoon trough. In addition, testosterone supports spermatogenesis, anabolism, and pubertal alterations. Master your testosterone and gain key insights to your endocrine system with some of PathDirect’s hormone packages today!

References

1. Bhasin S, Cunningham GR, Hayes FJ, et al. Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2010;95: 2536–59. Search PubMed

Testosterone secretion in males follows a circadian rhythm, with a peak at 7-9 am and trough in late afternoon.

(1) Testosterone and other androgens: physiology, pharmacology, and therapeutic use. In DeGroot LJ (Ed). Endocrinology. 2010.

2. NIH:National Institute of Health September 23, 2013

3. National Library of Medicine. Multiple Articles. https://www.ncbi.nlm.nih.gov/