Lexicon
Testosterone
Definition
Testosterone is a crucial male sex hormone that plays pivotal roles in spermatogenesis and sexual function and contributes significantly to metabolism, psychology, and cardiovascular health. [1] Male hypogonadism is a clinical syndrome that results from failure to produce physiological concentrations of testosterone, normal amounts of sperm, or both. [2] Late-onset hypogonadism combines low concentrations of circulating testosterone with specific symptoms associated with impaired hormone production in the ageing male. [3]
How it works
Aging exerts profound effects on the hypothalamic-pituitary-gonadal axis and Leydig cells, precipitating an age-induced decline in testosterone that adversely affects male health. [1] Hypogonadism may arise from testicular disease (primary hypogonadism) or from dysfunction of the hypothalamic-pituitary unit (secondary hypogonadism). [2] Testosterone and cortisol are respectively the main anabolic and catabolic signals in men, and sleep loss and lower sleep duration are associated with lower testosterone concentrations. [4] Testosterone is an anabolic hormone that rises acutely after resistance exercise, with high-volume protocols stressing a large Muscle Mass producing the greatest hormonal elevations relevant to tissue growth and remodelling [5]
Connected concepts
How it's measured
The recommended initial diagnostic test is a fasting morning total testosterone concentration measured with an accurate and reliable assay, with the diagnosis confirmed by repeating the morning fasting measurement. [6] When total testosterone is near the lower limit of normal or the patient has a condition that alters sex hormone-binding globulin, a free testosterone concentration should be obtained by equilibrium dialysis or estimated using an accurate formula. [6] The clinical diagnosis of hypogonadism is made on the basis of signs and symptoms consistent with androgen deficiency together with low morning testosterone concentrations in serum on multiple occasions. [2]
What levels mean
A diagnosis of hypogonadism should be made only in men with symptoms and signs consistent with testosterone deficiency and unequivocally and consistently low serum testosterone concentrations.
Community knowledge
## Interpretation Beyond the Lab Number
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- 1.Cheng H, Zhang X, Li Y, Cao D, Luo C, Zhang Q, Zhang S, Jiao Y. Age-related testosterone decline: mechanisms and intervention strategies. Reprod Biol Endocrinol · 2024
- 2.Basaria S. Male hypogonadism. Lancet · 2014
- 3.Salonia A, Rastrelli G, Hackett G, Seminara SB, Huhtaniemi IT, Rey RA, Hellstrom WJG, Palmert MR. Paediatric and adult-onset male hypogonadism. Nat Rev Dis Primers · 2019
- 4.Liu PY, Reddy RT. Sleep, testosterone and cortisol balance, and ageing men. Rev Endocr Metab Disord · 2022
- 5.Kraemer WJ, Ratamess NA. Hormonal responses and adaptations to resistance exercise and training. Sports Med · 2005
- 6.Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, Snyder PJ, Swerdloff RS. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.
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