Many studies have shown cross-sectional (and two small studies, longitudinal) declines in total and/or free testosterone (T) levels, with age, in men. The extent to which decline in T is the result of the aging process per se, as opposed to chronic illness, medication use, and other age-related factors, remains controversial. The frequency with which aging leads to T levels consistent with hypogonadism has also not been defined. These issues bear on the potential use of T replacement in aging men, because aging and hypogonadism have, in common, reduced bone and lean body mass and muscle strength and increased total and abdominal fat. We measured T and sex hormone-binding globulin (SHBG), by RIA, in stored samples from 890 men in the Baltimore Longitudinal Study on Aging. Using a mixed-effects model, we found independent effects of age and date of sampling to reduce T levels. After compensating for date effects, which investigation suggested was artifactual, we observed significant, independent, age-invariant, longitudinal effects of age on both T and free T index (free T index = T/SHBG), with an average change of -0.124 nmol/L.yr and -0.0049 nmol T/nmol SHBG.yr. T, but not free T index, also decreased with increasing body mass index. Use of beta-blocking drugs was associated with higher T and higher free T index levels. Using total T criteria, incidence of hypogonadal T levels increased to about 20% of men over 60, 30% over 70 and 50% over 80 yr of age, and even greater percentages when free T index criteria were employed. Our observations of health factor independent, age-related longitudinal decreases in T and free T, resulting in a high frequency of hypogonadal values, suggest that further investigation of T replacement in aged men, perhaps targeted to those with the lowest serum T concentrations, are justified.

/pdf/longitudinal-effects-of-aging-on-serum-total-and-free-3ge3qog98w.pdf

Longitudinal Effects of Aging on Serum Total and Free Testosterone Levels in Healthy Men

To evaluate the hypothesis that endocrine profiles change with aging independently of specific disease states, we examined the age trends of 17 major sex hormones, metabolites, and related serum proteins in 2 large groups of adult males drawn from the Massachusetts Male Aging Study, a population-based cross-sectional survey of men aged 39-70 yr conducted in 1986-89. Group 1 consisted of 415 men who were free of obesity, alcoholism, all prescription medication, prostate problems, and chronic illness (cancer, coronary heart disease, hypertension, diabetes, and ulcer). Group 2 consisted of 1294 men who reported 1 or more of the above conditions. Each age trend was satisfactorily described by a constant percent change per yr between ages 39-70 yr. Free testosterone declined by 1.2%/yr, and albumin-bound testosterone by 1.0%/yr. Sex hormone-binding globulin (SHBG), the major serum carrier of testosterone, increased by 1.2%/yr, with the net effect that total serum testosterone declined more slowly (0.4%/yr) than the free or albumin-bound pools alone. Among the major androgens and metabolites, androstane-3 alpha,17 beta-diol (androstanediol; 0.8%/yr) and androstanediol glucuronide (0.6%/yr) declined less rapidly than free testosterone, while 5 alpha-dihydrotestosterone remained essentially constant between ages 39-70 yr. Androstenedione declined at 1.3%/yr, a rate comparable to that of free testosterone, while the adrenal androgen dehydroepiandrosterone (3.1%/yr) and its sulfate (2.2%/yr) declined 2-3 times more rapidly. The levels of testosterone, SHBG, and several androgen metabolites followed a parallel course in groups 1 and 2, remaining consistently 10-15% lower in group 2 across the age range of the study. Subgroup analyses suggested that obese subjects might be responsible for much of the group difference in androgen level. Serum concentrations of estrogens and cortisol did not change significantly with age or differ between groups. Of the pituitary gonadotropins, FSH increased at 1.9%/yr, LH increased at 1.3%/yr, and PRL declined at 0.4%/yr, with no significant difference between groups 1 and 2.(ABSTRACT TRUNCATED AT 400 WORDS)

Age, disease, and changing sex hormone levels in middle-aged men: results of the Massachusetts Male Aging Study.

Male reproductive function and semen.

Calculation of free and bound fractions of testosterone and estradiol-17 beta to human plasma proteins at body temperature.

Aging in men is accompanied by a progressive, but individually variable decline of serum testosterone production, more than 20% of healthy men over 60 yr of age presenting with serum levels below the range for young men. Albeit the clinical picture of aging in men is reminiscent of that of hypogonadism in young men and decreased testosterone production appears to play a role in part of these clinical changes in at least some elderly men, the clinical relevancy of the age-related decline in sex steroid levels in men has not been unequivocally established. In fact, minimal androgen requirements for elderly men remain poorly defined and are likely to vary between individuals. Consequently, borderline androgen deficiency cannot be reliably diagnosed in the elderly, and strict differentiation between “substitutive” and “pharmacological” androgen administration is not possible. To date, only a few hundred elderly men have received androgen therapy in the setting of a randomized, controlled study, and many of th...

https://www.hormonebalance.org/images/documents/Kauffman%2005%20TDS%20REVIEW%20ER.pdf

The decline of androgen levels in elderly men and its clinical and therapeutic implications.

Age related changes and interrelationships between plasma testosterone, oestradiol and testosterone-binding globulin in normal adult males.

In 231 psychiatric in-patients, the 1 mg or 1.5 mg DST with blood samples at 0900 h, 1600 h and 2300 h and a post-dexamethasone plasma cortisol threshold of greater than or equal to 5 micrograms/dl were tested for their differential diagnostic utility in clinical psychiatry. Neither test significantly separated endogenous depressed patients from patients with other depressive or non-depressive psychiatric disorders. Studies of the 1 mg or 1.5 mg DST in 75 healthy subjects revealed about 12% of cortisol non-suppressors, when a post-dexamethasone cortisol threshold of greater than or equal to 5 micrograms/dl was used. This seemed to be an unacceptably low specificity of the test in normal subjects. A threshold criterion of greater than or equal to 8 micrograms/dl, however, yielded only 2.7% of non-suppressed normal subjects. Analyses of the DST data of the psychiatric patients, using a cortisol threshold of greater than or equal to 8 micrograms/dl, also failed to reveal a significantly higher specificity of the DST for endogenous depression. However, it was demonstrated that intervening variables such as stress due to hospital admission, drug withdrawal, suicidal turmoil, weight loss, as well as a low dexamethasone plasma level, enhance the rate of abnormal DST results in psychiatric in-patients, regardless of their diagnostic classification.

The limited utility of the dexamethasone suppression test for the diagnostic process in psychiatry.

The age related changes on free plasma testosterone (T), dihydrotestosterone (DHT) and oestradiol (OE2) were determined in 82 healthy adult males. Forty-six subjects were between 22 and 61 years of age (group I), 36 between 67 and 93 years (group II). The percentage of free, non protein bound hormone was determined by equilibrium dialysis of undiluted plasma against isotonic phosphate buffer at 37 degrees C. Total hormone concentrations were measured by radioimmunoassay. The percentage of free T was 2.24% (median), 1.65-3.42 (95 percentiles) in group I and 1.65% (1.24-2.26) in group II. The percentage of free DHT decreased from 1.17% (0.80-2.03) in group I to 0.83% (0.52-1.55) in group II. The decrease in % free Oe2 was only very small: group I = 2.49% (2.13-2.96), ad group II = 2.31% (1.95-3.17). The fall in free T by 43.3% from 12.2 ng/100 ml (6.74-25.0) in group I to 6.90 ng/ml (3.57-10.6) in group II was twice as high as that of total T, which decreased on an average by 20.6%. Free DHT decreased by 25.8%: group I = 578 pg/100 ml (266-987), group II =429 pg/100 ml (168-723), while total DHT was not significantly different between the two groups (-1.9%). Free Oe2 was increased in old age: group I = 42.4 PG/100 ML (26.0-69.4), GROUP II = 55.7 PG/100 ML (35.8-118.9). The increase in free Oe2 by 31.4% was almost as high as that of the total Oe2 (46.9%).

Age related changes in free plasma testosterone, dihydrotestosterone and oestradiol.

The 24-h sleep-wake pattern of plasma LH was studied in 18 patients with severe weight loss. Sixteen patients had anorexia nervosa, one suffered from schizophrenia and one had a gastric ulcer. The age of the patients ranged from 13 to 31 years. Seventeen women and one boy participated in the study. Their weight ranged from 51 to 73% of the ideal body weight (IBW) at the first 24-h study which was at one week after admission to the hospital. Blood was taken through an indwelling venous catheter every 30 min. The patients' weight increased under behavioural therapy and they were re-studied when they had gained approximately 10% IBW and again prior to release from the psychiatric ward. The LH patterns were classified as infantile, pubertal or adult. All patients except for two had an infantile pattern at the first study. Except for the two patients who had no anorexia nervosa, all developed a pubertal and/or an adult pattern. All patients whose weight was below 69% IBW had an infantile LH pattern. All patients whose weight was below 69% IBW had an infantile LH pattern. Adult patterns were only seen when the body weight was greater than 80% IBW. The increase of the average 24-h LH values was slower the older the patients were and the longer they had been anorectic.

Twenty-four hour sleep-wake pattern of plasma LH in patients with anorexia nervosa.

The response of plasma testosterone, LH and FSH to oral administration of cortisol or dexamethasone was studied for 26 h in 6 groups of 12 normal adult males. Twenty-four hour treatment with cortisol (60 mg at 1000 h, followed by 30 mg at 2 h intervals) or with dexamethasone (6 mg at 1000 h, followed by 3 mg at 6 h intervals) was without effect on testosterone during the day but suppressed the nocturnal rise completely. LH and FSH did not decrease at any time during the day and showed a highly significant increase during the second part of the night. Short-term treatment (1000–1600 h, 1600–2200 h or 2400 h–0800 h) with cortisol was less effective in suppressing the nocturnal rise in testosterone. It was concluded that administration of cortisol leading to plasma levels as seen under treatment with ACTH suppresses testosterone by abolishing or flattening the nocturnal rise. This effect was not mediated by changes in LH or FSH. Our data suggest that the ACTH-induced suppression of testosterone is d...

Cortisol-induced suppression of plasma testosterone in normal adult males

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Peter Doerr

Author Tools

Chat about Author