Serum total testosterone

Fitzgerald RL, Herold DA. 1996. Serum total testosterone immunoassay compared with negative chemical ionization gas chromatography—mass spectrometry. Clin Chem 42 749-755. 

In an open comparative study of androgenetic alopecia in 90 men oral finasteride (1 mg/day for 12 months n = 65) was compared with 5% topical minoxidil solution twice daily (n = 25) (22). The cure rates were 80% for oral finasteride and 52% for topical minoxidil. The adverse effects were all mild, and did not lead to withdrawal of treatment. Of the 65 men given oral finasteride, six had loss of libido, and one had an increase in body hair at other sites irritation of the scalp was seen in one of those who used minoxidil. These adverse events disappeared as soon as the treatment was withdrawn. The laboratory data did not show any statistically or clinically significant changes from baseline values to the endpoint, except for the serum total testosterone concentration, which was increased, and free testosterone and serum prostate-specific antigen in the finasteride group which were reduced from baseline values. 

In an open study in 35 women with acne, mean age 21 years, spironolactone 100 mg/day on 16 days each month for 3 months had no effect on serum total testosterone concentrations but reduced serum dehydroepiandroster-one sulfate concentrations (1075). 

Endocrine In 77 men with coronary heart disease atorvastatin 40-80 mg/day and for 12 weeks had no significant effects on serum total testosterone, free testosterone, sex hormone-binding globulin, luteinizing hormone, or follicle stimulating hormone compared with 83 men who took 10-20 mg/day [42 "]. 

Harman SM et al Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab 2001 86 724. [PMID 11158037]... 

Azizi et al. (1995) investigated changes in serum concentrations of reproductive hormones and sperm counts in men who had been exposed to sulfur mustard during wartime. In 16 individuals, serum free and total testosterone and dehydroepiandrosterone were markedly decreased in the first five weeks after exposure but levels returned to normal by 12 weeks. In 28 of 42 men evaluated one to three years after exposure, sperm counts were less than 30 million ceUs/mL and follicle-stimulating hormone was increased compared to controls having sperm counts above 60 million cells/mL. Testicular biopsy of the test subjects revealed partial or complete arrest of spermatogenesis. 

Either serum or heparinized plasma is used to measure total or free testosterone. Testosterone is subject to a diurnal variation, reaching a peak concentration between 0400 hours and 0800 hours. Therefore, morning specimens are preferred. Specimens are stable for a week (men) or 3 days (women) refrigerated and for up to 1 year frozen at 20 No steroids, thyroid, ACTH, estradiol, or gonadotropin medications should be given for 48 hours before sample collection. Most assays are standardized for serum or heparinized plasma. Other anticoagulants such as ethylene-diaminetetraacetic acid (EDTA) may give different values. In certain RIA assays, presence of EDTA appears to cause a 10% decrease in total testosterone concentrations. ... 

Reference intervals for total testosterone in serum are listed in Table Reference concentrations for total testos-... 

Only a small fraction (1% to 2%) of imconjugated testosterone exists fireely (non-protein bound) in serum or plasma. None of the conventional assay methods, including RIA, is sufficiently sensitive to quantify the free steroid directly in a protein-free ultrafiltrate of plasma. Instead, the free steroid is estimated in plasma by adding a known amount of radiolabeled compound to the sample and allowing labeled and unlabeled compounds to reach equilibrium in their competition for the same binding sites on the proteins. Bound and free radiolabeled fractions are then separated and the ratio of free labeled to total labeled compound is determined. At equilibrium, this ratio is taken as a measure of the free testosterone fraction. An estimate of serum free testosterone can then be calculated by multiplying the free testosterone fraction by the total testosterone concentration. 

Some men with osteoporosis possess clearly identifiable risk factors. In others, further investigation for secondary canses is warranted (see above patient assessment section). Men 70 years and older should have DXA tests to screen for osteoporosis. DXA standards state T-scores shonld be compared with a white male normative reference database, regardless of ethnicity. BMD determination shonld also be considered for men with a low-tranma fracture, prevalent vertebral deformity, glucocorticoid use, hypogonadism, alcoholism, or poor overall health. Measmement of serum free or total testosterone can also determine if hypogonadism is contributing to bone loss. 

In a similar type of data collection, during 2000 to 2001 Wozniak (2002) examined the incidence of anabolic hormone residues in 5393 animals, consisting of cattle, pigs, horses, rabbits, chickens, geese, turkeys, ducks, and fish. Wozniak assayed for residues of diethylstibestrol, hexesterol, dienestrol, zeranol, trenbolone, and 19-noresterone. In addition, 632 cattle and swine were assayed for medroxyprogesterone and 1176 were assayed for natural 17-p-estradiol and testosterone. In only three heifers and two cows did serum testosterone exceed the MRL (EC 0.5 pg per liter) two bulls and four cows had an increased content of 17-(3-estradiol in their blood. A total of 11 animals of the 5393 examined (0.2%) had excessive quantities of hormone materials in their system. None of the other animals showed evidence of the presence of... 

Egeland GM, Sweeney MH, Flngerhut MA, Wille KK, SchnorrTM, Halperin WE (1994) Total serum testosterone and gonadotropins in workers exposed to dioxin. Am J Epidemiol, 139(3) 272-281. 

Thyroid Effects. Limited information is available on thyroid effects in PBDE-exposed humans. There are suggestive occupational data as shown by effects that included increased serum FSH, low or borderline low serum T4, and increased thyroid antimicrosomal antibody titers in workers exposed to decaBDE and/or unspecified PBBs. There was no clear association between plasma levels of 2,2, 4,4-tetraBDE and thyroid hormone levels (free and total T3 and T4, TSH, free testosterone, follicle-stimulating hormone, lutenizing hormone, and prolactin) in men who consumed varying amounts of fatty fish from the Baltic Sea. Based on consistent evidence in animals, as summarized below, the thyroid is particularly sensitive to PBDEs and is a likely target of toxicity in exposed humans. 

Polybrominated Diphenyl Ethers. A limited amount of epidemiological irrformation is available for PBDEs. Plasma levels of various organohalogen compounds, including the congener 2,2, 4,4-tetraBDE, as well as serum hormone levels (free and total T3 and T4, TSH, free testosterone, follicle-stimulating... 

Testosterone (T) Female Abdomen, forearm MDTS spray solution Pharmacokinetic parameters Average and maximum serum concentrations of free and total T were significantly higher after application to the forearm compared to the abdomen V... 

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