Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Clin Endocrinol (Oxf) ; 101(1): 42-50, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38446525

RESUMEN

OBJECTIVE: Human choriogonadotrophin (hCG) treatment of gonadotrophin-deficient infertile men uses hCG of urinary (uhCG) or recombinant (rhCG) origin, but these treatments have not been compared nor are there studies defining rhCG dosing in men. DESIGN: hCG products were studied in randomized cross-over single-dose studies of standard (Study 1, 1500 IU and 62.5 µg, respectively) or high (Study 2, 5000 IU and 250 µg) dose and a multi-dose population pharmacology study of hCG use. PARTICIPANTS: Eight (Study 1) and seven (Study 2) volunteers in cross-over and 52 gonadotrophin-deficient men in the multi-dose study MEASUREMENTS: In cross-over studies, serum testosterone (T), dihydrotestosterone (DHT) and estradiol by liquid chromatography-mass spectrometry (LCMS) and serum hCG, LH, FSH, SHBG and T (observational study) by immunoassays. RESULTS: After standard and high-dose injection, serum hCG and testosterone responses had similar timing and peak concentrations except for a mildly lower early (<48 h) serum testosterone with uhCG. In the multi-dosing study, both hCGs had similar pharmacokinetics (pooled half-life 5.8 days, p < .001), while serum testosterone concentrations were stable after injection and did not differ between hCG products. Bench testing verified that 20% of pens from 4/10 individuals were used inappropriately. CONCLUSIONS: Although hCG pharmacokinetics are not formally bioequivalent, the similar pharmacodynamic effects on serum testosterone indicate that at the doses tested both hCGs provide comparable clinical effects. The starting dose of rhCG for treating gonadotrophin-deficient men should be 62.5 µg (6 clicks) of the rhCG pen.


Asunto(s)
Gonadotropina Coriónica , Estudios Cruzados , Proteínas Recombinantes , Testosterona , Humanos , Masculino , Gonadotropina Coriónica/administración & dosificación , Gonadotropina Coriónica/orina , Testosterona/sangre , Testosterona/administración & dosificación , Testosterona/orina , Adulto , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/farmacocinética , Hormona Luteinizante/sangre , Hormona Luteinizante/orina , Dihidrotestosterona/sangre , Dihidrotestosterona/orina , Estradiol/sangre , Relación Dosis-Respuesta a Droga , Hormona Folículo Estimulante/sangre , Hormona Folículo Estimulante/orina , Adulto Joven , Persona de Mediana Edad , Infertilidad Masculina/tratamiento farmacológico , Infertilidad Masculina/orina , Infertilidad Masculina/sangre , Globulina de Unión a Hormona Sexual/análisis
2.
Andrology ; 12(4): 891-898, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-37889046

RESUMEN

BACKGROUND: The effects of novel non-cytotoxic and immunotherapy drugs for cancer treatment on human testicular function have not been studied systematically. OBJECTIVES: The present study aimed to characterize effects of non-cytotoxic and immunotherapy drugs in patients with cancers who had not been previously treated with gonadotoxic chemo- or radiotherapy. MATERIALS AND METHODS: This study involved 34 men, not previously treated with gonadotoxic regimens, in a mixed longitudinal (Cohort 1: 19 men about to start and approximately 1 year on non-cytotoxic and immunotherapy treatment) and cross-sectional (Cohort 2: 15 men already on non-cytotoxic and immunotherapy treatment) study using data modeling to estimate within-person time-course changes in testicular exocrine and endocrine functions. Cohort 1 provided 45 paired semen and blood samples (34 prior to and nine during treatment) and Cohort 2 provided 45 sets of samples (15 pre-treatment, 30 on treatment), including six men in Cohort 2 who had pre-treatment spermatozoa cryostorage prior to the study. Men on non-cytotoxic and immunotherapy treatment had undergone a median of 33.5 months long-term treatment. RESULTS: Spermatozoa output and concentration were reduced by about 50%, with corresponding increases in serum follicle-stimulating hormone and decreases in serum inhibin B. Serum testosterone, luteinizing hormone, and sex hormone-binding globulin were unaffected by non-cytotoxic and immunotherapy treatment. CONCLUSION: Within limits of the present study of sample size and duration of on-non-cytotoxic and immunotherapy treatment, non-cytotoxic and immunotherapy drugs have a modest effects on testicular exocrine function (sperm production) or its hormonal correlates (follicle-stimulating hormone, inhibin B), with minimal impact on testicular endocrine (testosterone, luteinizing hormone) function.


Asunto(s)
Semen , Testículo , Humanos , Masculino , Estudios Transversales , Hormona Folículo Estimulante , Hormona Luteinizante , Testosterona , Inmunoterapia/efectos adversos , Inhibinas
3.
Eur J Endocrinol ; 190(1): 54-61, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38141148

RESUMEN

OBJECTIVE: Serum testosterone measurements in clinical practice mostly utilize "direct" (non-extraction) immunoassays which have method-specific bias due to steroid cross-reactivity and nonspecific matrix artifacts. Although more accurate, sensitive, and specific liquid chromatography-mass spectrometry (LCMS) dominates in clinical research, the within-person variability of serum testosterone in healthy men using LCMS measurement is not reported. DESIGN: Longitudinal multi-sampling observational study of men in excellent health over 3 months. METHODS: Elite healthy men (n = 325) over 40 years of age in excellent, asymptomatic health provided 9 blood samples over 3 months with serum testosterone, dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) measured by validated LCMS with conventional biochemical and anthropometric variables. RESULTS: Quantitative estimates of within-person variability within day and between day, week, month, and quarter were stable other than an increase due to fasting. The androgen biomarkers most sensitive to age and testosterone among widely used biochemical and anthropometric variables in middle-aged and older men were identified. CONCLUSIONS: This study provides estimates of variability in serum testosterone and the best androgen biomarkers that may prove useful for future studies of androgen action in male ageing.


Asunto(s)
Andrógenos , Testosterona , Persona de Mediana Edad , Masculino , Humanos , Anciano , Adulto , Estradiol , Dihidrotestosterona , Ayuno , Biomarcadores
4.
J Steroid Biochem Mol Biol ; 141: 113-20, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24495617

RESUMEN

Non-steroidal drugs that increase endogenous testosterone (T) may be used to exploit ergogenic effects of androgens in power sports. While superactive GnRH analog use is suspected, neither screening nor detection tests are developed. This study aimed to determine if (a) stimulation for 5 days by leuprolide (a superactive GnRH analog) of serum and urine steroids and urine LH is reproducible at a 2 week interval, (b) nandrolone decanoate (ND) co-administration masks responses to leuprolide administration, (c) performance of urine measurement of leuprolide and M1, its major metabolite, as a detection test. Healthy men were randomized into a 4 week parallel group, open label clinical study in which all men had daily sc injections of leuprolide (1mg) for 4 days in the 1st and 3rd weeks with hormone-free 2nd and 4th weeks. In the 3rd week, men were randomized to either ND injections or no extra treatment. Serum steroids were determined by liquid chromatography, tandem mass spectrometry (LC-MS), urine steroids by gas chromatography, mass spectrometry (GC-MS), urine leuprolide and M1 by high resolution LC-MS and urine LH by immunoassay. Leuprolide stimulated striking, reproducible increases in serum and urine LH and steroids (serum T, dihydroT (DHT), 3α diol; urine T, epitestosterone (E) and androsterone (A). ND suppressed basal serum T, E2, 3α diol, and urinary E but did not mask or change the magnitude of responses to leuprolide. Urine leuprolide and M1 measurement had 100% sensitivity and specificity in detecting leuprolide administration up to one day after cessation of injections with the detection window between 1 and 3 days after last dose. Screening using urine steroid and LH measurements, optimally by urinary log10(LHxT), correctly classified 82% of urine samples. It is concluded that leuprolide stimulation of endogenous testosterone is reproducible after a 10-day interval, is not masked by ND and is reliably detected by urine leuprolide or M1 measurement for at least 1 day after administration.


Asunto(s)
Leuprolida/administración & dosificación , Hormona Luteinizante/sangre , Sustancias para Mejorar el Rendimiento/administración & dosificación , Testosterona/sangre , Adulto , Dihidrotestosterona/sangre , Dihidrotestosterona/orina , Doping en los Deportes , Estradiol/sangre , Estradiol/orina , Humanos , Leuprolida/farmacocinética , Leuprolida/orina , Hormona Luteinizante/orina , Masculino , Persona de Mediana Edad , Nandrolona/análogos & derivados , Nandrolona/farmacología , Nandrolona Decanoato , Sustancias para Mejorar el Rendimiento/farmacocinética , Sustancias para Mejorar el Rendimiento/orina , Testosterona/orina , Adulto Joven
5.
Clin Endocrinol (Oxf) ; 77(5): 755-63, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22563890

RESUMEN

OBJECTIVE: To determine serum concentrations, intra-individual variability and impact of age-related co-morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E(2)) and estrone (E(1)) in older men. DESIGN: Observational, repeated measures study. PARTICIPANTS: Men (n = 325) with 40 years and older self-reporting very good or excellent health. MEASUREMENTS: Standardized history, physical examination and collection of nine blood samples at fixed time intervals were measured over 3 months (three at 20 min intervals on days 1 (fasting) and 2 (non-fasting), one at days 7, 30 and 90). Serum T, DHT, E(2) and E(1) (n = 2900, > 99% of scheduled samples) measured by liquid chromatography-tandem mass spectrometry (LC-MS) were analysed by linear mixed model analysis with fasting, age and obesity as covariables. RESULTS: Mean serum T did not vary with age (P = 0·76) but obesity (-0·35 nM per body mass index (BMI) unit, P < 0·0001) and ex-smoker status (-1·6 nM, P < 0·001) had significant effects. Serum DHT was increased with age (+0·011 nM per year, P = 0·001) but decreased with obesity (-0·05 nM per BMI unit, P < 0·0001). Serum E(2) did not vary with age (P = 0·31) or obesity (P = 0·12). Overnight fasting increased (by 9-16%, all P < 0·001) and reduced variability in morning serum T, DHT, E(2) and E(1). Non-fasting serum T and DHT were stable over time (day, week, month or 3 months; P > 0·28). CONCLUSIONS: Serum T, DHT and E(2) displayed no decrease associated with age among men over 40 years of age who self-report very good or excellent health although obesity and ex-smoking status were associated with decreased serum androgens (T and DHT) but not E(2). These findings support the interpretation that the age-related decline in blood T accompanying non-specific symptoms in older men may be due to accumulating age-related co-morbidities rather than a symptomatic androgen deficiency state.


Asunto(s)
Dihidrotestosterona/sangre , Estradiol/sangre , Testosterona/sangre , Anciano , Humanos , Masculino , Persona de Mediana Edad
6.
Asian J Androl ; 14(3): 476-80, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22522506

RESUMEN

Objective studies of men's reproductive function are hindered by their reliance on: (i) self-reporting to quantify sexual activity and (ii) masturbation to quantify sperm output rendering both types of estimate vulnerable to unverifiable subjective factors. We therefore examined whether detection of spermatozoa and measurement of prostate-specific antigen (PSA) in urine could provide objective semiquantitative estimates of sperm output and recent ejaculation, respectively, using widely available laboratory techniques. Of 11 healthy volunteers who provided urine samples before and at intervals for 5 days after ejaculation, sperm was present in 2/11 men before, and in all 11/11 samples immediately after ejaculation, but by the second and subsequent void, spermatozoa were present in ∼10%. PSA was detectable at high levels in all urine samples, peaking at the first post-ejaculatory sample but returning to baseline levels by the second post-ejaculatory void. We conclude that urinary spermatozoa and PSA are objective biomarkers for sperm production and sexual activity, but only for a short-time window until the first post-ejaculatory urine void. Hence, for a single urine specimen, the presence of spermatozoa and PSA are valid biomarkers, reflecting sperm production and recent ejaculation only until the next micturition, so their measurement should be restricted to the first morning urine void.


Asunto(s)
Abstinencia Sexual/fisiología , Conducta Sexual/fisiología , Espermatogénesis/fisiología , Espermatozoides/citología , Orina/citología , Adulto , Biomarcadores/orina , Eyaculación/fisiología , Humanos , Masculino , Antígeno Prostático Específico/orina , Recuento de Espermatozoides , Espermatozoides/fisiología , Factores de Tiempo , Adulto Joven
7.
Ann Intern Med ; 153(10): 621-32, 2010 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-21079217

RESUMEN

BACKGROUND: Benign prostatic hypertrophy increases with age and can result in substantially decreased quality of life for older men. Surgery is often required to control symptoms. It has been hypothesized that long-term administration of a nonamplifiable pure androgen might decrease prostate growth, thereby decreasing or delaying the need for surgical intervention. OBJECTIVE: To test the hypothesis that dihydrotestosterone (DHT), a nonamplifiable and nonaromatizable pure androgen, reduces late-life prostate growth in middle-aged men. DESIGN: Randomized, placebo-controlled, parallel-group trial. (Australian New Zealand Clinical Trials Registry number: ACTRN12605000358640) SETTING: Ambulatory care research center. PARTICIPANTS: Healthy men (n = 114) older than 50 years without known prostate disease. INTERVENTION: Transdermal DHT (70 mg) or placebo gel daily for 2 years. MEASUREMENTS: Prostate volume was measured by ultrasonography; bone mineral density (BMD) and body composition were measured by dual-energy x-ray absorptiometry; and blood samples and questionnaires were collected every 6 months, with data analyzed by mixed-model analysis for repeated measures. RESULTS: Over 24 months, there was an increase in total (29% [95% CI, 23% to 34%]) and central (75% [CI, 64% to 86%]; P < 0.01) prostate volume and serum prostate-specific antigen level (15% [CI, 6% to 24%]) with time on study, but DHT had no effect (P > 0.2). Dihydrotestosterone treatment decreased spinal BMD (1.4% [CI, 0.6% to 2.3%]; P < 0.001) at 24 months but not hip BMD (P > 0.2) and increased serum aminoterminal propeptide of type I procollagen in the second year of the study compared with placebo. Dihydrotestosterone increased serum DHT levels and its metabolites (5α-androstane-3α,17ß-diol and 5α-androstane-3ß,17ß-diol) and suppressed serum testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormone levels. Dihydrotestosterone increased hemoglobin levels (7% [CI, 5% to 9%]), serum creatinine levels (9% [CI, 5% to 11%]), and lean mass (2.4% [CI, 1.6% to 3.1%) but decreased fat mass (5.2% [CI, 2.6% to 7.7%]) (P <0.001 for all). Protocol-specific discontinuations due to DHT were asymptomatic increased hematocrit (n = 8), which resolved after stopping treatment, and increased prostate-specific antigen levels (n = 3; none with prostate cancer) in the DHT group. No serious adverse effects due to DHT occurred. LIMITATION: Negative findings on prostate growth cannot exclude adverse effects on the natural history of prostate cancer. CONCLUSION: Dihydrotestosterone treatment for 24 months has no beneficial or adverse effect on prostate growth but causes a decrease in spinal but not hip BMD. These findings have important implications for the wider use of nonsteroidal pure androgens in older men. PRIMARY FUNDING SOURCE: BHR Pharma.


Asunto(s)
Andrógenos/administración & dosificación , Dihidrotestosterona/administración & dosificación , Próstata/efectos de los fármacos , Próstata/crecimiento & desarrollo , Administración Cutánea , Antígenos de Neoplasias/sangre , Composición Corporal/efectos de los fármacos , Densidad Ósea/efectos de los fármacos , Colágeno Tipo I/sangre , Dihidrotestosterona/sangre , Método Doble Ciego , Estradiol/sangre , Proteínas Fetales , Geles , Humanos , Hormona Luteinizante/sangre , Masculino , Persona de Mediana Edad , Fragmentos de Péptidos , Procolágeno , Próstata/diagnóstico por imagen , Antígeno Prostático Específico/sangre , Hiperplasia Prostática/prevención & control , Testosterona/sangre , Ultrasonografía
8.
Clin Endocrinol (Oxf) ; 71(3): 417-28, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19170708

RESUMEN

CONTEXT: The administration of gonadotrophins is prohibited in sport but the effect in men of recently available recombinant hCG and LH on serum and urine concentrations of gonadotrophins and androgens has not been systematically evaluated in the antidoping context. OBJECTIVE: To determine the time-course of recombinant LH (rhLH) and hCG (rhCG) on blood and urine hormone profiles in men to develop effective tests to detect rhLH and rhCG doping. DESIGN: Two randomized controlled studies with a 2 x 2 factorial design. SETTING: Academic research centre. PARTICIPANTS: Healthy male volunteers aged 18-45 years. INTERVENTIONS: In the rhLH study, men were randomized into (i) either of two single doses of rhLH (75 IU or 225 IU), and (ii) suppression of endogenous LH and testosterone by nandrolone or no suppression. In the rhCG study, men were randomized into (i) either of two single doses of rhCG (250 or 750 microg), and (ii) suppression of endogenous LH and testosterone by nandrolone decanoate (ND) or no suppression. ND suppression comprised a single dose of 200 mg ND 3 days prior to, and in the rhCG study an additional dose 1 day after gonadotrophin injection. MAIN OUTCOME MEASURES: Serum and urine hCG, LH, T, T : LH ratio, urine epitestosterone (E) and urine T : E ratio. RESULTS: Neither rhLH dose produced a significant increase in serum or urine LH or T or in the T : E or T : LH ratios regardless of ND-induced suppression of endogenous LH and T. Nor did an even higher dose (750 IU) in three healthy men with unsuppressed gonadal axis. These findings were confirmed with two different commercial LH immunoassays together with adjustment for any influence of urine sediment and dilution. Both rhCG doses produced a steep, dose-proportional increase in serum and urine hCG with increases in serum and urine T and suppression of serum and urine LH, regardless of hCG dose. Serum but not urine T was lowered by ND suppression. The T : LH ratio showed a progressive increase unrelated to rhCG dose or ND suppression, whereas both rhCG and ND suppression minimally increased T : E ratio. CONCLUSIONS: Both rhCG doses produce a striking increase in serum hCG and T with suppression of serum LH but, at single doses up to 750 IU, rhLH has no influence on serum or urine LH or T. Effective rhLH doping, which relies on a sustained increases in endogenous T, would require much higher and more frequent daily rhLH doses. Use of LH immunoassays optimized for serum to detect rhLH doping by urine LH measurement requires more standardization and validation and, at present, is unreliable. The T : LH ratio is, however, a useful screening test for hCG doping although its utility requires further evaluation.


Asunto(s)
Andrógenos/sangre , Gonadotropina Coriónica/administración & dosificación , Hormona Luteinizante/administración & dosificación , Testosterona/sangre , Adolescente , Adulto , Andrógenos/orina , Gonadotropina Coriónica/sangre , Gonadotropina Coriónica/orina , Doping en los Deportes , Humanos , Hormona Luteinizante/sangre , Hormona Luteinizante/orina , Masculino , Persona de Mediana Edad , Proteínas Recombinantes/administración & dosificación , Testosterona/orina , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...