Metabolic clearance rate of testosterone in male epileptic patients on anti-convulsant therapy

1991 ◽  
Vol 129 (3) ◽  
pp. 465-468 ◽  
Author(s):  
M. J. Wheeler ◽  
B. K. Toone ◽  
A. Dannatt ◽  
P. B. C. Fenwick ◽  
S. Brown
Keyword(s):  
Clearance Rate ◽  
Patient Population ◽  
Free Testosterone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Testosterone Concentration ◽  
The Mean ◽  
Low Testosterone

ABSTRACT There are several reports which state that male epileptics on anti-convulsant therapy have reduced sexual activity. We and others have shown that, although total testosterone is raised, the free testosterone concentration is reduced in this patient population. This could be a result of an increased metabolic clearance rate (MCR) of testosterone, inadequate secretion of LH to stimulate testosterone synthesis or inappropriately low testosterone production by the Leydig cells. We have examined these possibilities by measuring the MCR of testosterone in 15 male epileptics on anti-convulsant therapy. In this group of patients, the mean LH (9·3±5·9 IU/l) and sex-hormone binding globulin (SHBG) (54·5±22·9 nmol/l) concentrations were significantly greater than those of five normal control subjects (4·7±1·11 IU/l and 26·0 ±7·0 nmol/l respectively). Mean total testosterone concentrations of the two groups were not significantly different but the mean percentage of free testosterone and free testosterone concentration were significantly lower in the patient population (2·06±0·43 vs 2·98±0·27 and 0·56±1·1 vs 0·79±0·7 pmol/l). The MCR of testosterone was significantly lower in the patients (773±322 vs 1354±443 1/day) and showed a positive correlation with the percentage of free testosterone. Therefore, our results suggest that the lowered free testosterone in male epileptics on anti-convulsant therapy is not due to an increased MCR of testosterone. The increased LH concentration suggests primary hypogonadism. This, in turn, could be responsible for low free testosterone levels in the presence of normal testosterone. Journal of Endocrinology (1991) 129, 465–468

scholarly journals The analog free testosterone assay: are the results in men clinically useful?

1998 ◽  
Vol 44 (10) ◽  
pp. 2178-2182 ◽  
Author(s):  
Stephen J Winters ◽  
David E Kelley ◽  
Bret Goodpaster
Keyword(s):  
Free Testosterone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Serum Concentrations ◽  
Testosterone Concentration ◽  
Low Testosterone ◽  
Relationship Of ◽  
The Relationship ◽  
Constant Percentage

Abstract Men with low testosterone concentrations are usually hypogonadal. However, because variations in the testosterone transport protein, sex hormone-binding globulin (SHBG), directly influence the total testosterone concentration, confirmation of a low testosterone with a measurement of free testosterone or “bioavailable” testosterone (BAT) is recommended. In the present study, we examined the relationship of SHBG with free testosterone (Coat-A-Count assay, Diagnostic Products) and with BAT in men (n = 29) and women (n = 28) who participated in a study of the metabolic determinants of body composition. As expected, total testosterone was strongly positively correlated with SHBG among men (r = 0.68; P <0.01). Although the BAT was independent of SHBG in men (r = 0.02), SHBG was an important predictor of free testosterone (r = 0. 62; P <0.01). In contrast, in women serum concentrations of total testosterone (r = −0.26; P = 0.17), free testosterone (r = −0.30; P = 0.17), and BAT (r = −0.46; P = 0.013) all tended to be lower with increasing SHBG. Free testosterone was nearly perfectly positively correlated with total testosterone (r = 0.97) in men, among whom free testosterone represented a relatively constant percentage of the total testosterone (0.5–0.65%), and the percentage of free testosterone was unrelated to SHBG. Thus the Coat-A-Count free testosterone concentration in men, like the total testosterone concentration, is determined in part by plasma SHBG. Accordingly, androgen deficiency may be misclassified with this assay in men with low SHBG. Moreover, the previous findings of reduced free testosterone concentrations with hypertension or hyperinsulinemia or as a risk factor for developing type 2 diabetes, conditions in which SHBG is reduced, may have been methodology-related.

scholarly journals In men older than 70 years, total testosterone remains stable while free testosterone declines with age. The Health in Men Study

2007 ◽  
Vol 156 (5) ◽  
pp. 585-594 ◽  
Author(s):  
Bu B Yeap ◽  
Osvaldo P Almeida ◽  
Zoë Hyde ◽  
Paul E Norman ◽  
S A Paul Chubb ◽  
...  
Keyword(s):  
Free Testosterone ◽  
Older Men ◽  
Early Morning ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Limited Data ◽  
Cross Sectional ◽  
Testosterone Concentration ◽  
Age Related ◽  
Clinical Consequences

Objective: An age-related decline in serum total and free testosterone concentration may contribute to ill health in men, but limited data are available for men > 70 years of age. We sought to determine the distribution and associations of reduced testosterone concentrations in older men. Design: The Health in Men Study is a community-representative prospective cohort investigation of 4263 men aged ≥ 70 years. Cross-sectional hormone data from 3645 men were analysed. Methods: Early morning sera were assayed for total testosterone, sex hormone binding globulin (SHBG) and LH. Free testosterone was calculated using the Vermeulen method. Results: Mean (± s.d.) serum total testosterone was 15.4 ± 5.6 nmol/l (444 ± 162 ng/dl), SHBG 42.4 ± 16.7 nmol/l and free testosterone 278 ± 96 pmol/l (8.01 ± 2.78 ng/dl). Total testosterone correlated with SHBG (Spearman’s r = 0.6, P < 0.0001). LH and SHBG increased with age (r = 0.2, P < 0.0001 for both). Instead of declining, total testosterone increased marginally (r = 0.04, P = 0.007) whilst free testosterone declined with age (r = −0.1, P < 0.0001). Free testosterone was inversely correlated with LH (r = −0.1, P < 0.0001). In multivariate analyses, increasing age, body mass index (BMI) and LH were associated with lower free testosterone. Conclusions: In men aged 70–89 years, modulation of androgen action may occur via an age-related increase in SHBG and reduction in free testosterone without a decline in total testosterone concentration. Increasing age, BMI and LH are independently associated with lower free testosterone. Further investigation would be required to assess the clinical consequences of low serum free testosterone, particularly in older men in whom total testosterone may be preserved.

scholarly journals The importance of SHBG and calculated free testosterone for the diagnosis of symptomatic hypogonadism in HIV-infected men: a single-centre real-life experience

Infection ◽  
2020 ◽  
Author(s):  
Letizia Chiara Pezzaioli ◽  
Eugenia Quiros-Roldan ◽  
Simone Paghera ◽  
Teresa Porcelli ◽  
Filippo Maffezzoni ◽  
...  
Keyword(s):  
Life Experience ◽  
Real Life ◽  
Free Testosterone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Sexual Symptoms ◽  
Low Testosterone ◽  
Gonadal Status ◽  
Spearman’S Correlation

Abstract Purpose The prevalence of low testosterone and symptoms of hypogonadism in HIV-infected men is still debated. We aimed to estimate the prevalence and type of hypogonadism in HIV-infected males complaining about sexual symptoms, and to evaluate the role of calculated free testosterone (cFT) vs total testosterone (TT) for diagnosis. Furthermore, we evaluated relationship between sex hormone-binding globulin (SHBG), gonadal status and clinical and virologic parameters. Methods We retrospectively evaluated 169 HIV-infected men with sexual symptoms, with TT available. Among them, we selected 94 patients with TT, SHBG, cFT, and luteinizing hormone (LH) available, and classified hypogonadism into overt (low TT and/or low cFT) and compensated (high LH, normal TT and cFT). Comparison was performed by non-parametric Kruskal–Wallis test and Spearman’s correlation was calculated to verify the possible associations. Results Overt and compensated hypogonadism were found in 20.2% and 13.8% of patients, respectively. With reliance on TT alone, only 10.6% of patients would have met diagnosis. SHBG values were elevated in one third of patients, and higher in men with compensated hypogonadism. Significant positive correlation was found between SHBG and HIV infection duration, TT and LH. Conclusion Only a complete hormonal profile can properly diagnose and classify hypogonadism in HIV-infected men complaining about sexual symptoms. TT alone reliance may lead to half of diagnoses missing, while lack of gonadotropin prevents the identification of compensated hypogonadism. This largely comes from high SHBG, which seems to play a central role in the pathogenesis of hypogonadism in this population.

Peripheral hormone levels in healthy subjects during controlled fasting

1986 ◽  
Vol 113 (3) ◽  
pp. 457-462 ◽  
Author(s):  
Ragnar Tegelman ◽  
Pia Lindeskog ◽  
Kjell Carlström ◽  
Åke Pousette ◽  
Rolf Blomstrand
Keyword(s):  
Protein Binding ◽  
Testosterone Level ◽  
Healthy Subjects ◽  
Free Testosterone ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Metabolic Clearance ◽  
Dehydroepiandrosterone Sulphate ◽  
Hormone Binding

Abstract. The effect of one week of controlled fasting (3 1 of fluid containing 50 g of carbohydrate/day) upon the serum levels of hormones, sex hormone binding globulin, and albumin was studied in healthy subjects. Fasting caused decreased levels of prolactin and T3, no changes in the levels of TSH, FSH, LH, dehydroepiandrosterone, 4-androstene-3,17-dione, total oestrone, and total testosterone, and increased levels of cortisol, dehydroepiandrosterone sulphate and albumin. A significant positive correlation was found between albumin and dehydroepiandrosterone sulphate. Fasting rapidly increased the levels of sex hormone binding globulin and decreased the percentage of free testosterone and the calculated free testosterone level in both sexes. A decreased metabolic clearance of certain steroids (cortisol, dehydroepiandrosterone sulphate) owing to an increased protein binding may be one of the endocrine consequences of fasting. An increased protein binding of testosterone may be outweighed by a decreased gonadal production, thus resulting in an unchanged total testosterone level. The increased sex hormone binding globulin level could not be explained by changes in gonadal and thyroid hormones.

scholarly journals Changes in Testosterone Levels and Sex Hormone-Binding Globulin Levels in Extremely Obese Men after Bariatric Surgery

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Patchaya Boonchaya-anant ◽  
Nitchakarn Laichuthai ◽  
Preaw Suwannasrisuk ◽  
Natnicha Houngngam ◽  
Suthep Udomsawaengsup ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Hypogonadotropic Hypogonadism ◽  
Free Testosterone ◽  
Serum Levels ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Morbidly Obese ◽  
The Mean ◽  
A Prospective Study ◽  
Estradiol Levels

Objective.Obesity is a risk factor for hypogonadotropic hypogonadism in men. Weight loss has been shown to improve hypogonadism in obese men. This study evaluated the early changes in sex hormones profile after bariatric surgery.Methods.This is a prospective study including 29 morbidly obese men. Main outcomes were changes in serum levels of total testosterone (TT), free testosterone (cFT), SHBG, estradiol, adiponectin, and leptin at 1 and 6 months after surgery.Results.The mean age of patients was 31 ± 8 years and the mean BMI was 56.8 ± 11.7 kg/m2. Fifteen patients underwent Roux-en-Y gastric bypass and 14 patients underwent sleeve gastrectomy. At baseline, 22 patients (75.9%) had either low TT levels (<10.4 nmol/L) or low cFT levels (<225 pmol/L). Total testosterone and SHBG levels increased significantly at 1 month after surgery (p≤0.001). At 6 months after surgery, TT and cFT increased significantly (p≤0.001) and 22 patients (75.9%) had normalized TT and cFT levels. There were no changes in estradiol levels at either 1 month or 6 months after surgery.Conclusions. Increases in TT and SHBG levels occurred early at 1 month after bariatric surgery while improvements in cFT levels were observed at 6 months after bariatric surgery.

METABOLIC CLEARANCE RATE, PRODUCTION RATE, AND MAMMARY UPTAKE AND METABOLISM OF PROGESTERONE IN COWS

1975 ◽  
Vol 66 (2) ◽  
pp. 239-247 ◽  
Author(s):  
R. B. HEAP ◽  
A. HENVILLE ◽  
J. L. LINZELL
Keyword(s):  
Production Rate ◽  
Clearance Rate ◽  
Jugular Vein ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Tracer Kinetic ◽  
The Mean ◽  
Jersey Cows ◽  
Conscious Animals ◽  
Uptake And Metabolism

SUMMARY Tracer kinetic techniques have been used to measure the production rate, metabolic clearance rate and mammary uptake of progesterone in six experiments on two Jersey cows. The cows were surgically prepared so that the carotid artery, jugular vein and mammary vein concentrations of progesterone, and udder blood flow, could be determined in conscious animals without anaesthesia or stress. The mean production rate of progesterone was 173 ± 23·3 (s.e.m.) μg/min, with values ranging from 80 to 276 μg/min in pregnancy. The metabolic clearance rate was 22·5 ± 2·0 1/min, or 0·21 ± 0·025 1/min/kg metabolic body weight. The mammary uptake of progesterone was low, 3·1 ± 1·1 μg/min, and udder uptake accounted for about 3% of progesterone production rate. During [3H]progesterone infusion, radioactivity was transferred from blood to milk, probably by diffusion down a concentration gradient. Progesterone accounted for more than 88% of the ether-soluble radioactivity recovered from milk.

Metabolic clearance rate in sheep of a met-enkephalin analogue estimated by radioimmunoassay

1982 ◽  
Vol 93 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. E. Bolton ◽  
J. H. Livesey ◽  
R. A. Donald
Keyword(s):  
Clearance Rate ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Time Intervals ◽  
Naturally Occurring ◽  
Specific Radioimmunoassay ◽  
The Mean

A sensitive and specific radioimmunoassay developed for measuring the met-enkephalin analogue d-ala2-met(0)5-ol-enkephalin (DAMME) was used to study the pharmacokinetics of DAMME in the circulation of sheep. Plasma concentrations of DAMME were measured at varying time-intervals after an intravenous bolus injection or following a constant intravenous infusion of the analogue. The mean metabolic clearance rate of DAMME was 2·8 ml/min per kg, the mean circulating half-life was 52 min and the mean volume of distribution was 190 ml/kg. The longer circulating time of the analogue when compared with that of naturally occurring met-enkephalin would appear to explain its prolonged analgesic effect.

scholarly journals Effect of pregnancy on the metabolic clearance rate and the volume of distribution of oxytocin in the baboon

1998 ◽  
Vol 274 (5) ◽  
pp. E791-E795 ◽  
Author(s):  
Wlodzimierz B. Kowalski ◽  
Lubomir Diveky ◽  
Ramkrishna Mehendale ◽  
Michael Parsons ◽  
Laird Wilson
Keyword(s):  
Clearance Rate ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Arterial Access ◽  
Initial Dilution ◽  
Uterine Contractions ◽  
The Mean ◽  
Dilution Volume

Pharmacokinetic parameters of oxytocin (OT) metabolism were determined during the last third of pregnancy and again 4–8 wk after delivery in the baboon. Animals were placed on a tether system with venous and arterial access and a continuous monitoring of uterine contractions during gestation. Two methods of determining OT pharmacokinetics were utilized (bolus injection vs. continuous infusion). The metabolic clearance rate of OT as determined during the bolus trials ( n = 7) was 22.2 ± 1.5 ml ⋅ min−1 ⋅ kg−1in pregnancy and 16.3 ± 1.4 ml ⋅ min−1 ⋅ kg−1postpartum ( P < 0.05), respectively, and 23.7 ± 2.8 vs. 16.9 ± 3.7 ml ⋅ min−1 ⋅ kg−1( P < 0.05), respectively, as determined during the 1-h infusion trials ( n = 4). The initial dilution volume and the volume of distribution at steady state of OT after administration did not differ between pregnant and postpartum animals ( P > 0.05). The mean residence time (MRT) of OT was shorter during pregnancy, 7.7 ± 0.8 vs. 10.8 ± 1.2 min postpartum ( P < 0.05). In summary, OT metabolism during pregnancy in the baboon is characterized by 1) increased clearance rate (1.4-fold), 2) accelerated turnover due to the shorter MRT, and 3) unaltered distribution.

Decrease in serum testosterone concentration during treatment with tetracycline

1983 ◽  
Vol 103 (2) ◽  
pp. 269-272 ◽  
Author(s):  
M. O. Pulkkinen ◽  
J. Mäenpää
Keyword(s):  
Binding Capacity ◽  
Serum Testosterone ◽  
Free Testosterone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Serum Concentrations ◽  
Hormone Binding ◽  
Testosterone Concentration ◽  
Tetracycline Treatment ◽  
Cessation Of Treatment

Abstract. Serum concentrations of testosterone and the binding capacity of sex hormone binding globulin (SHBG) were measured on 2 days immediately preceding tetracycline treatment, on 3 days of treatment and on 2 days immediately after cessation of treatment. On the treatment days serum mean testosterone concentrations were significantly lower than on the control days (17 ± 0.9 vs 21 ± 0.8 nmol/l, P < 0.01). There were no differences in the SHBG. The 'free testosterone index' behaved like the total testosterone.

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