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The free and nonspecifically bound plasma hormone levels generally reflect the clinical situation more accurately than total plasma hormone levels. Hence, it is important to have reliable indexes of these fractions. The apparent free testosterone (T) concentration obtained by equilibrium dialysis (AFTC) as well as the fraction of serum T not precipitated by(More)
In distinction to the course of reproductive ageing in women, men do not experience a rapid decline of Leydig cell function or irreversible arrest of reproductive capacity in old age. Hence, strictu sensu, the andropause does not exist. Nevertheless, both spermatogenesis and fertility as well as Leydig cell function do decline with age, as shown by a(More)
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(More)
Sex steroid concentrations and 17 beta-hydroxy-steroid dehydrogenase and aromatase activities were determined in fat tissue removed at surgery or, in order to allow comparisons in different sites, postmortem. Except for dehydroepiandrosterone (DHEA) sulfate (DHEAS), there existed a positive tissue/plasma gradient for all steroids studied (testosterone,(More)
To test the reliability of a single plasma testosterone (T) or dihydrotestosterone (DHT) level, respectively, as a parameter of the long term hormonal milieu, plasma T and DHT levels were measured eight times, over a period of 50 weeks, in 169 middle-aged and elderly men with symptomatic benign prostatic hyperplasia, who were otherwise healthy. The results(More)
In obese men, sex hormone-binding globulin levels (SHBG) as well as total plasma testosterone (T) levels are decreased. Data concerning the levels of nonprotein-bound testosterone (FT) are discordant, with some researchers reporting normal levels, and other reporting decreased levels. The latter imply an impairment of the feedback regulation mechanism of FT(More)
To evaluate the effects of obesity on the hypothalamo-pituitary-testicular axis, we compared total and free (FT) testosterone (T), androstenedione, dehydroepiandrosterone and its sulfate, and 5 alpha-androstane-3 alpha, 17 beta-diol glucuronide, and estradiol levels in a group of 35 obese [body mass index (BMI), > 30] men (aged 17-61 yr) to levels in a(More)
  • A Vermeulen
  • 1976
The origin of plasma sex hormones in postmenopausal women was studied by determining plasma levels under basal conditions, after ACTH stimulation, and after dexamethasone suppression, as well as after hCG stimulation. Values obtained in postmenopausal women were compared with values observed during the follicular phase of the cycle in young women on the one(More)
The diagnosis of hypoandrogenism in the aging male is still difficult, since the symptomatology is aspecific and multifactorial, and it is unknown whether the androgen requirements of elderly men are the same as those of young men. Indeed, there are arguments for decreased (increased androgen feed-back sensitivity) as well as for increased (decreased(More)