A purification step prior to commercial sensitive immunoassay is necessary to achieve clinical usefulness when quantifying serum 17β-estradiol in prepubertal children

Ankarberg‐Lindgren, Carina; Norjavaara, Ensio

doi:10.1530/eje-07-0403

Cited by 53 publications

(49 citation statements)

References 23 publications

(28 reference statements)

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“…Serum E 2 concentrations were determined in duplicate by an assay which involves a diethyl ether extraction step prior to radioimmunoassay (Spectria® Estradiol RIA; Orion Diagnostica, Espoo, Finland) [1,6]. The extraction E 2 radioimmunoassay has been validated especially for pediatric use [6] and is accredited by the SWEDAC quality control agency in Sweden, SS-EN ISO 15189 (No.…”

Section: Methodsmentioning

confidence: 99%

Physiological Estrogen Replacement Therapy for Puberty Induction in Girls: A Clinical Observational Study

2014

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Background/Aim: The goal of estrogen replacement therapy (ERT) in girls with hypogonadism is to achieve the endocrine milieu similar to natural puberty, where transdermal administration is the most physiological route. The aim of the study was to evaluate guidelines for the induction of puberty with transdermal estradiol (E₂) patches in a large outpatient setting. Methods: In a retrospective study, serum E₂ levels from 18 clinics were analyzed at the Göteborg Pediatric Growth Research Center laboratory, as part of the initiation of ERT in girls with hypogonadism. Exclusion criteria were pubertas tarda and pubertal arrest. Eighty-eight observations (50 with Turner syndrome, TS) were included. Serum E₂ levels were determined by extraction + radioimmunoassay (detection limit 4 pmol/l) and analyzed in relation to the dose of Evorel® (25 µg/24 h, containing 1.60 mg estradiol hemihydrate; Janssen-Cilag Pharmaceutica N.V., Beerse, Belgium). Results: There was a linear relationship between serum E₂ and the weight-based dose, with r = 0.56, p < 0.0001 for all observations and r = 0.59, p < 0.0001 for the TS study group. Linear regression analysis for doses of 0.05-0.07 µg/kg resulted in serum levels of 17-23 pmol/l (TS 17-24 pmol/l) and doses of 0.08-0.12 µg/kg in 26-39 pmol/l (TS 27-39 pmol/l). Conclusions: For the initiation of ERT with nocturnally administered E₂ patches, we recommend reduced starting doses of 0.05-0.07 µg/kg, with the goal of mimicking E₂ levels during gonadarche. In older girls, when breast development is of high priority, the starting dose can still be 0.08-0.12 µg/kg.

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Section: Methodsmentioning

confidence: 99%

Physiological Estrogen Replacement Therapy for Puberty Induction in Girls: A Clinical Observational Study

2014

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“…Serum oestradiol (E 2 ) concentrations were determined using an assay that involves a diethyl ether extraction step prior to quantification by a modified RIA (Spectria Estradiol RIA, Orion Diagnostica; Espoo, Finland) as described previously (21). The lower limit of detection for the extraction RIA was 4 pmol/l.…”

Section: Methodsmentioning

confidence: 99%

Testicular size development and reproductive hormones in boys and adult males with Noonan syndrome: a longitudinal study

Ankarberg‐Lindgren¹,

Westphal²,

Dahlgren³

2011

European Journal of Endocrinology

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Objective: To characterise changes in testicular size and reproductive hormones and to investigate the aetiology of delayed puberty and impaired fertility in males with Noonan syndrome (NS). Design: In this study, 12 males with NS were longitudinally followed from pre/early puberty until adulthood. Of the 12 males, ten had no medical history other than NS and were divided into two groups, undescended testes (UT), and descended testes (DT) and compared with a reference population. Methods: Hormone concentrations in serum were determined by immunoassays and testicular volume was measured using an orchidometer. Results: Before puberty, reproductive hormone levels were within the expected range in almost all cases. In some cases, LH, FSH and testosterone and oestradiol (E 2 ) concentrations started to increase during puberty and inhibin B and anti-Mü llerian hormone (AMH) declined to subnormal levels. Most of the boys studied had small testes that, in the majority of cases, progressed to normal size in adulthood. No difference in reproductive hormones was observed between the UT and DT groups either during puberty or at adulthood. However, as adults, males with NS had higher LH (5.7 vs 4.0 U/l, P!0.01), FSH (7.1 vs 2.5 U/l, P!0.001), testosterone (18.7 vs 15.6 nmol/l, P!0.01) and E 2 (66 vs 46 pmol/l, P!0.001) levels and lower AMH (33 vs 65 pmol/l, P!0.01) and inhibin B (median 108 vs 187 pg/ml, P!0.01) levels than the reference population. Conclusions: In NS males, both Sertoli and Leydig cell dysfunction is common with reproductive hormone levels deteriorating progressively to adulthood.

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“…Sex hormone binding globulin (SHBG) levels were measured using solid-phase, chemiluminescent immunometric assays (Immulite 1000, Diagnostic Products Corporation, Los Angeles, CA, USA). Serum 17β-estradiol (E2) was determined in duplicate by extraction RIA as previously described 17 and testosterone levels as previously described 18 . E2 and testosterone were utilized together with SHBG in calculating the free E2 and free testosterone levels, respectively, according to a previously presented method 19 .…”

Section: Blood Samplingmentioning

confidence: 99%

Muscle function in monozygotic female twin pairs discordant for hormone replacement therapy

et al. 2011

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Introduction: Postmenopausal monozygotic twin pairs discordant for hormone replacement therapy (HRT) provide an advantageous study design controlling for genetic background for elucidating the relationships between aging, sex hormone levels, muscle strength, contractile capacity, and fatigability. Methods: Thirteen postmenopausal monozygotic twin pairs discordant for HRT were measured for maximal voluntary torque (MVC) and twitch characteristics using electrical stimulation before and after intermittent dynamic plantarflexor exercise until exhaustion. Results: Peak twitch torque was 32% higher in HRT users than in their non‐HRT, genetically identical sisters (P = 0.002), but MVC did not differ. There were no differences in the activation level or twitch time characteristics between the co‐twins. Fatigue caused decreases in MVC (P = 0.001), twitch torque (P = 0.001), time to peak (P = 0.013), and half‐relaxation time (P = 0.001) similarly in HRT users and non–HRT users. Conclusion: In early postmenopausal women, involuntary but not voluntary force‐generating mechanisms of the plantarflexors are augmented by the use of HRT. Muscle Nerve, 2011

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A purification step prior to commercial sensitive immunoassay is necessary to achieve clinical usefulness when quantifying serum 17β-estradiol in prepubertal children

Cited by 53 publications

References 23 publications

Physiological Estrogen Replacement Therapy for Puberty Induction in Girls: A Clinical Observational Study

Physiological Estrogen Replacement Therapy for Puberty Induction in Girls: A Clinical Observational Study

Testicular size development and reproductive hormones in boys and adult males with Noonan syndrome: a longitudinal study

Muscle function in monozygotic female twin pairs discordant for hormone replacement therapy

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