Regarding the references for reference chemicals of alternative methods.

The selection of reference and proficiency chemicals is an important basis for method validation and proficiency evaluations. Reference chemicals are a set of test substances used by a method developer to evaluate the reliability and relevance of a new method, in comparison to reference data (usually to a validated reference method). Proficiency chemicals, as defined in OECD Guidance Document on Good In Vitro Method Practices, are defined post validation as a subset of the reference chemicals or other chemicals with sufficient supporting data that are used by naïve laboratories to demonstrate technical competence with a validated test method. Proficiency chemicals should cover different physical states, several chemical classes within the applicability domain of the method and yield the full range of responses (in the validated reference method and in vivo), they shall be commercially available (at non-prohibitive costs) and have high quality reference data. If reference and subsequent proficiency chemicals are chosen without sufficient evidence for their inclusion, both test method evaluation and demonstration of technical proficiency can be hampered. In this report we present cases in which the selection of reference chemicals led to problems in the reproduction of the reference results and demonstration of technical proficiency: The variability of results was not always taken into account in selection of several reference substances of the LLNA (OECD TG 429). Based on the available reference data one proficiency chemical for the Corrositex skin corrosion test (OECD TG 435) should be replaced. Likewise, the expected in vitro result for one of the proficiency chemicals for the BCOP (OECD TG 437) was difficult to reproduce in several labs. Furthermore, it was not possible to obtain one of the proficiency chemicals for the Steroidogenesis Assay (OECD TG 456) at non-prohibitive costs at a reasonable purity. Based on these, we recommend changes of current proficiency chemicals lists with established OECD Test Guidelines and provide recommendations for developing future sets of reference chemicals.

Gas chromatography tandem mass spectrometry offers advantages for urinary steroids analysis.

Gas chromatography mass spectrometry has been the lynchpin of clinical assessment of steroid profiles for ∼3 decades. The improvements in assay performance offered by tandem mass spectrometry were assessed. Across the spectrum of glucocorticoid and androgen analytes tested, limits of detection and quantitation were ∼20 fold lower with triple than single quadrupole systems, but the more noticeable improvement was that signal to noise was substantially improved and the linear range wider. These benefits allowed more reliable and concomitant measurement of steroids with substantially different abundances and in smaller volumes of urine.

Terapia de privación de andrógenos y obesidad mórbida: ¿tienen en común el riesgo cardiovascular por síndrome metabólico? / Androgen Deprivation Therapy And Morbid Obesity: Do They Share Cardiovascular Risk Through Metabolic Syndrome?

Antecedentes: A pesar de que el uso de la terapia de privación de andrógenos (TPA) ha producido una mejora en la supervivencia de hombres con cáncer de próstata avanzado, el hipogonadismo resultante se asocia con efectos negativos acusados, comparables a los que se observan en la obesidad mórbida, estando el riesgo cardiovascular entre los más letales. Objetivos: Evaluar el síndrome metabólico, las anomalías metabólicas y el riesgo cardiovascular en pacientes con cáncer de próstata sometidos a TPA, sin TPA y con obesidad mórbida. Métodos: Se trata de un estudio transversal que incluye a 79 hombres con cáncer de próstata, de los cuales 54 están sometidos a TPA y en 25 está ausente esta terapia, incluyéndose también a 91 pacientes con obesidad mórbida agrupados por sexo y edad. Para definir el síndrome metabólico empleamos los criterios de la Federación Internacional de Diabetes (FID). Se compararonl as anomalías metabólicas, los marcadores metabólicos y la puntuación Framingham entre los pacientes en terapia TPA, sin terapia TPA y con obesidad mórbida con el fin de predecir el riesgo de enfermedad coronaria a 10 años. Resultados: Los pacientes en terapia TPA presentaron una incidencia mucho mayor de diabetes y obesidad centralizada, así como mayores niveles de colesterol total y lipoproteínas de baja densidad (LBD), en comparación con los varones eugonadales. El riesgo cardiovascular medio fue significativamente superior en pacientes sometidos a TPA (39,97±12,53% vs. 26,09±14,80%; p = 0,021). Los sujetos con obesidad mórbida tenían un mayor riesgo de enfermedad coronaria a 10 años, comparable a la de los pacientes sometidos a TPA (p = 0,054). Conclusión: Este estudio apunta a que en los pacientes sometidos a TPA la preponderancia de anomalías metabólicas y riesgos cardiovasculares es mayor, siendo similar a la observada en sujetos con obesidad mórbida. Es posible que ambos procesos tengan en común el riesgo cardiovascular por vía de síndrome metabólico (AU)

Background: Although the use of androgen deprivation therapy (ADT) has resulted in improved survival in men with advanced prostate cancer, the resulting hypogonadism is associated with profound adverse effects comparable to those found in morbid obesity, being cardiovascular risk among the most lethal. Objectives: Evaluate metabolic syndrome, metabolic abnormalities and cardiovascular risk in patients with prostate cancer under ADT, not under ADT and morbid obese men. Methods: This is a cross-sectional study that involves 79 men presenting prostate cancer, of whom 54 under ADT and 25 not under ADT and 91 morbidly obese patients paired by sex and age. To define metabolic syndrome, we used the International Diabetes Federation (IDF) criteria. Metabolic abnormalities, metabolic markers and Framingham score to predict the ten year coronary heart disease risk were compared among patients under ADT, not under ADT and morbid obese. Results: Patients under ADT presented significantly greater occurrence of diabetes and central obesity and higher levels of total cholesterol and low density lipoprotein (LDL) compared to eugonadal men. The mean cardiovascular risk was significantly higher in patients under ADT (39.97±12.53% vs. 26.09±14.80%; p = 0.021). Morbidly obese subjects had increased ten year coronary heart disease risk; comparable to patients under ADT (p = 0.054). Conclusion: This study suggests that patients under ADT show higher prevalence of metabolic abnormalities and cardiovascular risk similar to those found in morbidly obese subjects. It is possible that both processes share cardiovascular risk through metabolic syndrome (AU)

Use of genetically identical (clone) steers to determine the effects of estrogenic and androgenic implants on beef quality and palatability characteristics.

Six sets of four genetically identical Brangus steers (n = 24; mean weight = 413 kg, SD = 19.8) were used to study the effects of estradiol and trenbolone acetate on beef quality and palatability characteristics. Steers in each clone set were randomly assigned to the following treatment groups: 1) a nonimplanted control; 2) a single estrogenic implant, containing 20 mg of estradiol benzoate and 200 mg of progesterone; 3) a single androgenic implant, containing 140 mg of trenbolone acetate; or 4) a single combination implant, containing 24 mg of 17-beta estradiol and 120 mg of trenbolone acetate. Following implantation, the steers were fed a high-concentrate finishing diet for a period of 112 d. Compared with control steers, implanted steers had higher (P < .05) average daily gains and heavier (P < .05) finished live weights and carcass weights. However, there were no differences (P > .05) among treatment groups with respect to their effects on growth rate, live weight, carcass weight, dressing percentage, fat thickness, longissimus muscle area, percentage of kidney, pelvic, and heart fat, or USDA yield grade. Moreover, marbling scores for implanted steers were not statistically different from marbling scores for control steers. However, a comparison among implant types showed that steers implanted with the estrogenic implant had significantly lower marbling scores than did steers implanted with the androgenic or combination implants. Use of androgenic and combination implants had no effect (P > .05) on beef tenderness of strip loin, top sirloin, or top round steaks; however, use of estrogenic implants decreased (P < .05) tenderness of top sirloin steaks.

Prospects for new hormonal male contraceptives.

Overpopulation is a paramount global crisis, as it underlies virtually all major worldwide problems, including poverty, malnutrition, and warfare. It is imperative that proliferation be curbed by expediting reductions in fertility. This article discusses the demand for and acceptability of male contraceptives and the process of spermatogenesis. Endocrine control of spermatogenesis, and potential sites for disruption of male fertility, including steroid combinations and GnRH agonists and antagonists are reviewed also. Risks and benefits of these approaches are considered.

PIP: Despite a social trend in support of greater male involvement in fertility regulation, currently available male-oriented methods (e.g., condoms, coitus interruptus, and vasectomy) are flawed and lack widespread acceptability. Most experimental methods target the development, maturation, or ultimate function of sperm cells. This article focuses on efforts to develop an improved hormonal contraceptive for men that inhibits gonadotropin-releasing hormone (GnRH), gonadotropins, or both, using either exogenous steroids or GnRH analogs. Although GnRH antagonists suppress gonadotropins more rapidly and completely than any known agents and their pituitary effects are immediately reversible, these agents are currently unmarketable due to their high cost, insufficient potency, and impractical delivery systems. To ensure fertility, both follicle-stimulating hormone and intratesticular testosterone must be eliminated. Thus, any technique that suppresses gonadotropins must include testosterone replacement. The effects of prolonged testosterone administration on hypertrophy have not been determined. No candidate for reversible systemic male contraception is likely to achieve general marketability in the immediate future due to a combination of factors, including fundamental knowledge voids about the molecular control of spermatogenesis and a lack of financial support from pharmaceutical companies for research in this area.

Steroid profile for urine: reference values.

We describe a project, participated in by 24 institutions in The Netherlands and Belgium, to determine normal reference values for steroids in urine by capillary gas chromatography. Urine samples from 288 healthy volunteers were analyzed in triplicate. Reference values, expressed in mumol/24 h, were determined for androsterone, etiocholanolone, dehydroepiandrosterone, 11-keto-androsterone, 11-keto-etiocholanolone, 11-hydroxyandrosterone, 11-hydroxyetiocholanolone, pregnanediol, pregnanetriol, 11-desoxytetrahydrocortisol, tetrahydrocortisone, tetrahydrocortisol, allo-tetrahydrocortisol, and 17-keto- and 17-hydroxysteroids. We also determined reference ratios for etiocholanolone/androsterone, tetrahydrocortisone/tetrahydrocortisol, and tetrahydrocortisol/allo-tetrahydrocortisol; an upper limit of a discriminant function to establish polycystic ovarian disease; and reference values for 24-h urine volume and creatinine excretion. Reference values were determined separately for men and women, each in six age categories: 0-3 months, 4 months-12 years, 13-16 years, 17-50 years, 51-70 years, and older than 70 years. We conclude that these reference values are reliable and form a basis for quantitative interpretation of steroid profiles.