Testosterone Metabolic Clearance and Production Rates Determined by Stable Isotope Dilution/Tandem Mass Spectrometry in Normal Men: Influence of Ethnicity and Age

Wang, Christina; Catlin, Don H.; Starcevic, Borislav; Leung, A. F.; DiStefano, Emma; Lucas, G. H. W.; Hull, Laura; Swerdloff, Ronald S.

doi:10.1210/jc.2003-031802

Cited by 86 publications

(39 citation statements)

References 32 publications

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“…This anomaly may well be explained by a decreased testosterone production rate in older men. 79 The main reason for estimation of serum testosterone in men is detection of hypogonadism. In cases of proven hypogonadism satisfactory replacement of de¢-cient testosterone is relatively easily achieved, the main routes of administration being by bolus intra-muscular injection of mixtures of testosterone esters or by transdermal patches of testosterone.…”

Section: Presence and Effect Of Relevant Binding Proteinsmentioning

confidence: 99%

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men

Diver

2006

Ann Clin Biochem

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Most hospital laboratories estimate the concentration of total circulating testosterone using a non-extraction method on an automated multi-channel immunoassay analyser supplied by a small number of multi-national diagnostic companies. Although these platforms offer advantages of quick turnaround times, small volume sampling and random access analysis, proficiency testing schemes suggest the quality of results produced remains similar to that of the early manual radioimmunoassay. An estimate of the bioavailable, non-sex hormone binding globulin (SHBG) bound fraction of circulating testosterone, be that the free or the free plus albumin-bound, may be a better index of gonadal status than total testosterone alone, especially when a borderline hypogonadal level of total testosterone is found, and may avoid misclassification of hypogonadal or eugonadal men. Free or bioavailable testosterone may be calculated or measured. The free androgen index may not give a true reflection of androgen status in men. In the interpretation of serum testosterone concentrations with results 440 nmol/L, the possibility of exogenous administration or abuse needs to be considered. The marked diurnal rhythm in total testosterone should also be taken into account. There may be a diminution of testosterone secretion with advancing age, but the great majority of older men have a circulating total testosterone concentration well within the accepted reference intervals established for younger men. As testosterone concentration may fluctuate markedly both seasonally and from day to day, it may be judicious to measure levels on more than one occasion.Provided that estimates of serum testosterone are unequivocally eugonadal (12.5-40 nmol/L) or hypogonadal (o7.0 nmol/L), results produced by routine automated immunoassays will in all probability give a satisfactory assessment of androgen status in men.Routine biochemical assessment of gonadal function in men should include measurement of early morning luteininzing hormone, follicle stimulating hormone, prolactin and SHBG together with total testosterone, and if necessary some estimate of bioactive testosterone.

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Section: Presence and Effect Of Relevant Binding Proteinsmentioning

confidence: 99%

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men

Diver

2006

Ann Clin Biochem

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“…34,35 The 5a-reduced steroids dihydrotestosterone, 3a-17b androstanediol glucuronide and androsterone glucronide levels and their ratios to testosterone are lower in East Asian men, suggestive of lower 5a-reductase enzyme activity in the East Asians. [36][37][38] The contribution of baseline androgen levels and 5a-reductase enzyme activity to the ethnic differences in spermatogenesis suppression in response to exogenous androgen administration deserves further investigation.…”

Section: Differences In Hormone Concentrations and Metabolismmentioning

confidence: 99%

Does ethnicity matter in male hormonal contraceptive efficacy?

Ilani¹,

Liu²,

Swerdloff³

et al. 2011

Asian J Androl

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The development of male hormonal contraception has progressed significantly during the last three decades. The ultimate goal is to produce an effective, safe and reversible male method of contraception that are within reach of and can be used by all men globally. This review aims to outline the recent developments in male hormonal contraception with special emphasis on how ethnicity influences acceptability, extent of sperm suppression, and rate of recovery of spermatogenesis. Baseline differences in testicular histomorphology and testosterone metabolism between East Asian and Caucasian men have been reported, but whether this contributes significantly to varying degrees of sperm suppression in response to exogenous testosterone therapy is less known. Testosterone alone male hormonal contraceptive regimens are effective and applicable for East Asian men, and less so for Caucasians. Combinations of progestins with androgens are sufficient to optimize effectiveness of suppression and applicability to all ethnicities. New compounds such as steroidal or non-steroidal selective androgen receptor modulators with dual androgenic and progestational activities are potential compounds for further development as male hormonal contraceptive methods. At the present time, combined androgen and progestin contraceptive regimens appear to be effective, safe, reversible and convenient to use for all men with ethnic, cultural and environmental differences. Further refinements on the hormonal agent, methods of delivery, and dose optimization of the androgen relative to the progestin are necessary. This goal mandates further investment and large clinical trials in multiethnic populations to better define safety and efficacy.

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“…4 Currently, TRT in Korea is a commonly used LOH treatment modality and is prescribed not only by urologists, but also by primary physicians. Because most studies investigating the effects of TRT on LOH have been released by Western centres and because ethnicity may affect serum testosterone levels, [5][6][7][8][9] data on the effects of TRT in Asian populations are needed. In this review, we summorize the results of studies on TRT in the Korean population and discuss the implications of these findings for TRT in general.…”

Section: Introductionmentioning

confidence: 99%

Testosterone replacement therapy for late-onset hypogonadism: current trends in Korea

Ko¹,

Kim²

2011

Asian J Androl

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Testosterone levels in men older than 40 years can decrease at a rate of 1%-2% per year, and reports show that more than 50% of 80-year-old men have testosterone levels consistent with hypogonadism. Late-onset hypogonadism (LOH) is a clinical and biochemical syndrome associated with advancing age and characterized by typical symptoms of serum testosterone deficiency. In recent decades, the concept of LOH in ageing men has become familiar in European countries and the United States. It is also a topic of interest and debate throughout Korea. However, most of the data regarding advantages or disadvantages of testosterone replacement therapy (TRT) as treatment for LOH have been primarily obtained from studies on Western populations; therefore, studies of the effects of TRT in Asian men, who may have different serum testosterone compared to Western men, are needed. TRT is commonly prescribed in Korea, despite the paucity of studies on the effects of TRT in Asian populations. Data from various TRT studies based on Korean have shown its efficacy in increasing serum testosterone levels and improving subjective symptoms as assessed by questionnaires. Currently, patches and short-acting intramuscular injections are displaced by gels and long-acting formulations. However, to prevent overdiagnosis and overtreatment, indication for TRT should include both low testosterone levels and symptoms and signs of hypogonadism. Keywords: androgens; androgenic agents; late-onset hypogonadism; testosterone replacement therapy INTRODUCTION Late-onset hypogonadism (LOH) is a clinical and biochemical syndrome associated with advancing age resulting from age-related changes in the interactions between hypothalamus/pituitary factors and testicular factors. This syndrome is characterized by typical symptoms of serum testosterone deficiency. Increased longevity and population ageing are expected to result in an increase in the number of men with LOH. Therefore, social interest in testosterone replacement therapy (TRT) has increased over the past few decades.In recent decades, LOH in ageing men has become common in European countries and the United States, 1,2 and it has also attracted interest in Korea. An epidemiological research study conducted via email of 5795 Korean men of at least 40 years of age, using the Androgen Deficiency in Aging Men (ADAM) questionnaire, revealed that 64.6% of respondents had symptoms of LOH, and more than 50% of respondents complained of a decline in erection, endurance and/or sexual desire. When asked whether they intended to undergo TRT, 96% of respondents who complained of erectile dysfunction and decreased endurance and/or sexual desire said that they would accept treatment. 3 To provide appropriate guidelines for investigation, treatment and monitoring of LOH in ageing Korean men, the academic committee of the Korean Society for Aging Male Research released guidelines on LOH in men in 2006. 4 Currently, TRT in Korea is a commonly used LOH treatment modality and is prescribed not only by urologists, but also...

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Testosterone Metabolic Clearance and Production Rates Determined by Stable Isotope Dilution/Tandem Mass Spectrometry in Normal Men: Influence of Ethnicity and Age

Cited by 86 publications

References 32 publications

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men

Does ethnicity matter in male hormonal contraceptive efficacy?

Testosterone replacement therapy for late-onset hypogonadism: current trends in Korea

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