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Background. Immunoassays have been criticized for poor accuracy at low testosterone concentrations. Mass spectrometry (MS) has been proposed as the only reliable method for testosterone determination. The aim of this study was to compare a sensitive testosterone radioimmunoassay (RIA) with results from different MS. Methods. We compared testosterone concentrations determined by a sensitive testosterone RIA, lower limit of detection 0.03 nmol/L and limit of quantitation 0.1 nmol/L, with four tandem MS that were included in an international external quality assessment program for laboratory medicine. We also compared the morning concentrations of testosterone in girls and boys at different pubertal stages, using results from the RIA, with reported values determined by LC-MS/MS, developed for androgen determination in children. Results. The mean (SD), concentrations were similar between RIA and MS: 1.5 (0.3) and 1.4 (0.4) in the child/women range (0.8-2.6 nmol/L) and 16.0 (3.7) and 17.8 (4.5) nmol/L for the adult male range (10.1-30.0 nmol/L), respectively. The ratio between RIA and MS versus results from mean values of the four MS methods was 1.0 (0.18); 1.1 (0.18) for child/women concentrations and 0.9 (0.13) for male testosterone concentrations. Furthermore, compared to the pediatric reference values determined by LC-MS/MS, the sensitive testosterone RIA delivered similar testosterone values across the different pubertal stages. Conclusions. The comparison between different tandem MS methods and a sensitive testosterone RIA illustrates that there are immunoassays that deliver clinically useful information in prepubertal and pubertal children. [ABSTRACT FROM AUTHOR]

Background/Aims: To study serum testosterone and estradiol in healthy boys in relation to growth during puberty up to peak height velocity (PHV). Methods: Growth velocity was analyzed through testosterone (n = 41) and 17β-estradiol (n = 37) 24-hour profiles in a dose-response model. Participants were 26 healthy boys admitted for short or tall stature or participating as healthy volunteers at the Queen Silvia Children's Hospital. Other inclusion criteria included the following: gestational age 37-42 weeks, birth weight and length >-2 standard deviation score (SDS) and prepubertal height and weight within ±3 SDS. Testosterone was measured using a modified radioimmunoassay (RIA) with a detection limit of 0.03 nmol/l. Estradiol was determined using an ultrasensitive extraction RIA with a detection limit 4 pmol/l. A sixth-grade polynomial was fitted to each child's growth data, giving growth velocity and age at PHV. Results: Growth velocity increased by 50% from prepubertal growth to PHV at a morning testosterone level of 3.1 nmol/l (95% confidence interval 2.4-4.2), EC50. The corresponding EC50 of 17β-estradiol was 6.5 pmol/l (3.2-13). Boys approaching PHV (<4% remaining) had morning testosterone levels >10 nmol/l and 17β-estradiol >9 pmol/l. Conclusion: Observed early puberty/initial mid puberty morning testosterone levels of 2.4-4.2 nmol/l are associated with a 50% increase in growth velocity from prepubertal growth to PHV in healthy boys. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The role of estrogens in male physiology has become evident. However, clinically useful normative data for estradiol secretion in boys has not previously been established due to the insensitivity of current methods used in clinical routine. By use of a validated ultra-sensitive extraction RIA, our aim was to establish normative data from a group consisting of healthy boys in prepuberty and during pubertal development. Methods: Sixty-two 24-hours serum profiles (6 samples/24 hours) were obtained from 44 healthy boys (ages; 7.2-18.6 years) during their pubertal development, classified into five stages: prepuberty (testis, 1-2 mL), early (testis, 3-6 mL), mid (testis, 8-12 mL), late-1 (testis,15-25 mL, not reached final height) and late-2 (testis,15-25 mL, reached final height). Serum estradiol was determined by an ultra- sensitive extraction radioimmunoassay with detection limit 4 pmol/L and functional sensitivity 6 pmol/L. Results: Mean estradiol concentrations during 24-hours secretion increased from prepuberty (median: <4 (5-95 percentiles: <4 - 7) pmol/L) to early puberty (6 (<4 - 12 pmol/L) but then remained relatively constant until a marked increase between mid-puberty (8 (4 - 17) pmol/L) and late-1 (21 (12 - 37) pmol/L) puberty, followed by a slower increase until late-2 puberty (32 (20 - 47) pmol/L). The diurnal rhythm of serum estradiol was non-measurable in pre- and early puberty, but discerned in mid-puberty, and become evident in late pubertal stages with peak values at 0600 to 1000 h. Conclusion: With the use of an ultra-sensitive extraction RIA, we have provided clinically useful normative data for estradiol secretion in boys. [ABSTRACT FROM AUTHOR]

Objective: The aim of this work was to investigate the prevalence of premature thelarche (PT) in 18-month-old girls, and the incidence of clinically evaluated PT for girls aged 18–36 months. Methods: In the prevalence substudy, a prospective population-based cohort of 3,140 girls born at Northern Älvsborg county hospital (NÄL) in Trollhättan, Sweden, was followed for 2 years. Girls with breast development at the 18-month health check were referred to one pediatric center in NÄL for evaluation. All girls with PT were included and followed for clinical outcome and 17β-estradiol. The prospective incidence substudy covered 8 years in a 10-year period and included all girls aged 18–36 months born at NÄL who were clinically evaluated for PT. Results: The prevalence of PT at 18 months in our cohort was 1.6/1,000. The 5 girls with PT no longer showed symptoms at the follow-up 3–6 months later. The incidence was 1.1/1,000 for girls aged 18–36 months and 1.0/1,000 for girls aged 18–30 months who were clinically evaluated for their PT. Conclusion: This is the first prospective population-based study of PT and it shows a prevalence of PT at age 18 months of 1.6/1,000. The incidence of clinically evaluated PT was 1.1/1,000. Our result is in line with other studies reporting the incidence of PT from medical records (0.4–40/1,000). The outcome of PT in our study, as in the other studies, is that the great majority of girls show only benign symptoms. [ABSTRACT FROM AUTHOR]

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. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: Age at adiposity rebound (AR) is associated with obesity and Type 2 Diabetes in adults. The aim of the present study was to investigate the role of age at AR in adult fat mass, fat distribution and pubertal timing for a Swedish cohort. Patients and Methods: This is a retrospective cohort study. Detailed growth charts were retrieved for the men participating in the population-based GOOD (Gothenburg Osteoporosis and Obesity Determinants) study (n = 573). Body composition was analysed using dual X-ray absorptiometry and computed tomography at 18-20 years of age. Age and BMI at AR were calculated using pediatric growth charts and AR was defined as the lowest BMI between 3 and 9 years of age. Results: Subjects were divided into early (age at AR below 5.4 years of age), middle (age at AR 5.4 to 6.8 years of age) and late (age at AR after 6.8 years of age) age at AR tertiles. Subjects in the early age at AR tertile had higher young adult BMI (+8%), whole body fat mass (+34%) and amount of subcutaneous adipose tissue (+61%) than the subjects in the middle and late tertiles (p,0.01). The early age at AR tertile had an increased risk of obesity (Odds Ratio 4.1 [95% CI 1.2-13.9]) compared with the middle and late tertiles. In addition, the early age at AR tertile had Peak Height Velocity (PHV) 7 months earlier than the late tertile. Conclusions: Early age at AR was associated with young adult obesity as a consequence of a high amount of subcutaneous adipose tissue in men. In addition we made the novel observation that early age at AR was associated with an early puberty in men. [ABSTRACT FROM AUTHOR]

The role of puberty and normal variations in pubertal timing for the development of obesity in men is unclear. The aim of the current study was to investigate the impact of pubertal timing and prepubertal BMI (kg/m²) for young adult BMI and fat mass distribution. Detailed growth charts from birth to age 18-20 years were retrieved for the men participating in the population-based Gothenburg Osteoporosis and Obesity Determinants study. Age at peak height velocity (PHV) and BMI at age 10 years were estimated for 579 subjects, and PHV was used as an assessment of pubertal timing. The fat mass characterization and distribution were analyzed using dual X-ray absorptiometry and peripheral as well as abdominal computed tomography at age 18.9 ± 0.5 years. We demonstrate that age at PHV is an independent negative predictor of young adult BMI and whole-body fat mass. Interestingly, age at PHV is an independent negative predictor of central, but not peripheral, fat mass. In contrast, BMI at 10 years of age predicts both central and peripheral subcutaneous fat mass. In conclusion, we demonstrate that early pubertal onset specifically predicts a central fat mass distribution, while a predominantly subcutaneous obese phenotype is strongly predicted by a high prepubertal BMI. Diabetes 55:3047-3052, 2006 [ABSTRACT FROM AUTHOR]

Background: Early onset of breast development in a young girl is usually a benign and isolated prepubertal condition, i.e., premature thelarche (PT), but can sometimes be progressive and the first sign of pubertal precocity (PP). Serum 17β-estradiol (17β-E2) level is a possible marker to differentiate between benign and pathological forms of breast development. We defined an upper serum 17β-E2 level for benign, “classic” PT for girls aged 9–48 months. Methods: Serum 17β-E2 was analysed with a highly sensitive extraction radioimmunoassay (RIA). Gonadotropins, Tanner breast stage, growth, other investigations, and clinical outcome were assessed in 125 girls with breast development, in a population-based study in West Sweden. Results: A total of 125 of 128 girls had a benign form of breast development with a mean serum 17β-E2 level of 15.2 pmol/L and a mean + 2 SD of 31 pmol/L, which was regarded as the upper limit for benign PT; 3 girls with PP had 17β-E2 levels above 70 pmol/L. Conclusion: This is the first study to define an upper serum 17β-E2 level associated with benign PT. Girls aged 9–48 months with PT and Tanner breast stage 2 have 17β-E2 levels below 32 pmol/L using extraction RIA. LH below the detection limit (0.1 IU/L) and measurable FSH support benign PT. [ABSTRACT FROM AUTHOR]

Aims: We studied whether first morning voided (FMV) urinary gonadotropin measurements could be used as a noninvasive alternative to the GnRH test in the assessment of the hypothalamic-pituitary-gonadal function in children. Methods: In a single-center study, we compared FMV urinary gonadotropin concentrations with basal and GnRH-stimulated serum gonadotropin levels in 274 children and adolescents (78 girls, 196 boys) aged 5-17 years referred for growth and pubertal disorders. The concordance between FMV urinary gonadotropin concentrations and GnRH test results was assessed. Results: FMV urinary LH (U-LH), urinary FSH (U-FSH) and their ratios correlated well with the corresponding basal and GnRH-stimulated serum parameters (r = 0.66, p < 0.001). Receiver operating characteristic curve analyses using urinary and serum LH and FSH concentrations showed that FMV U-LH and U-LH/U-FSH performed equally well as the GnRH test in the differentiation of early puberty (Tanner stage 2) from prepuberty (Tanner stage 1) (area under the curve 0.768-0.890 vs. 0.712-0.858). FMV U-LH and U-LH/UFSH performed equally well as basal serum LH in predicting a pubertal GnRH test result (area under the curve 0.90-0.93). Conclusion: FMV U-LH determination can be used for the evaluation of pubertal development and its disorders, reducing the need for invasive GnRH stimulation tests. [ABSTRACT FROM AUTHOR]

Abstract: Aims: To investigate the pharmacodynamics, pharmacokinetics and safety of the glucokinase activator AZD6370 after 1day of administration under fed and fasted conditions in patients with type 2 diabetes mellitus (T2DM). Methods: This was a two-part study. In Part A, patients received a single oral dose of AZD6370 (20, 60 or 180mg) or placebo in the fasted or fed states (both n =8). In Part B, patients (n =8) received placebo and a total dose of AZD6370 180mg given in one, two or four divided doses. Plasma glucose, insulin and C-peptide changes versus placebo were assessed. Results: AZD6370 provided dose-dependent reductions in plasma glucose of up to 30% versus placebo in both fasted and fed patients (p <0.001 at 60 and 180mg doses). Insulin secretion increased with dose, but absolute increases were relatively small in the fasted versus fed state (0–4h). Dosing AZD6370 twice or four-times over 1day gave a smoother 24-h glucose profile than single-dose. AZD6370 was rapidly absorbed. Pharmacokinetics of AZD6370 were dose-independent and unaffected by food. AZD6370 was generally well tolerated. Conclusions: AZD6370 produced dose-dependent glucose reductions and increased glucose-stimulated insulin secretion in patients with T2DM. [Copyright &y& Elsevier]

Aim: The objective of this study was to determine estradiol levels and assess their relationship to pubertal growth in girls. Methods: Thirty-seven 24-hour profiles of serum 17β-estradiol were retrospectively analyzed in relation to growth in 27 healthy girls admitted for short/tall stature (n = 20) or recruited as healthy volunteers at Göteborg Pediatric Growth Research Center (GP-GRC). Inclusion Criteria: Birth weight and length above -2 SDS, gestational age 37-42 weeks, prepubertal height and weight within ±3 SDS and normal growth hormone secretion. Serum estradiol was determined by a validated ultrasensitive extraction radioimmunoassay (detection limit 4 pmol/l). A sixth-grade polynomial was fitted to each girl's growth data. Growth velocity and age at peak height velocity (PHV) was calculated. Results: A dose-response model was used to find the morning 17β-estradiol level at which half of the maximal pubertal growth up to PHV had occurred, EC50, which was 20 pmol/l with a 95% confidence interval of 13-31. When 17β-estradiol exceeds early pubertal levels (Tanner breast stage 2, 10-51 pmol/l), less than 25% of the potential pubertal growth velocity up to PHV remains. Conclusions: Morning 17β-estradiol in the low early pubertal range (13-31 pmol/l) is associated with increasing growth velocity. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: The amount of visceral adipose tissue is a risk factor for the metabolic syndrome. It is unclear how BMI changes during childhood and adolescence predict adult fat distribution. We hypothesized that there are critical periods during development for the prediction of adult subcutaneous and visceral fat mass by BMI changes during childhood and adolescence.Research Design and Methods: Detailed growth charts were retrieved for the men participating in the population-based Gothenburg Osteoporosis and Obesity Determinants (GOOD) Study (n = 612). Body composition was analyzed using dual-energy X-ray absorptiometry and adipose tissue areas using abdominal computed tomography at 18 to 20 years of age.Results: The main finding in the present study was that subjects with increases in BMI Z score of more than 1 SD during adolescence had, independent of prepubertal BMI, both larger subcutaneous (+138%; P < 0.001) and visceral adipose tissue areas (+91%; P < 0.001) than subjects with unchanged BMI Z-score. In contrast, subjects with increases in BMI Z score of more than 1 SD during late childhood had a larger amount of adult subcutaneous adipose tissue (+83%; P < 0.001) than subjects with unchanged BMI Z score but an unaffected amount of visceral adipose tissue. BMI changes during adolescence predict both visceral and subcutaneous adipose tissue of the abdomen, whereas BMI changes during late childhood predict only the subcutaneous adipose tissue.Conclusions: The amount of visceral adipose tissue in young adult men was associated with BMI changes specifically during adolescence, whereas the amount of subcutaneous adipose tissue was associated with BMI changes during both late childhood and adolescence. [ABSTRACT FROM AUTHOR]

OBJECTIVE--The amount of visceral adipose tissue is a risk factor for the metabolic syndrome. It is unclear how BMI changes during childhood and adolescence predict 'adult fat distribution. We hypothesized that there are critical periods during development for the prediction of adult subcutaneous and visceral fat mass by BMI changes during childhood and adolescence. RESEARCH DESIGN AND METHODS--Detailed growth charts were retrieved for the men participating in the population-based Gothenburg Osteoporosis and Obesity Determinants (GOOD) Study (n = 612). Body composition was analyzed using dual-energy X-ray absorptiometry and adipose tissue areas using abdominal computed tomography at 18 to 20 years of age. RESULTS--The main finding in the present study was that subjects with increases in BMI Z score of more than 1 SD during adolescence had, independent of prepubertal BMI, both larger subcutaneous (+138%; P < 0.001) and visceral adipose tissue areas (+91%; P < 0.001) than subjects with unchanged BMI Z-score. In contrast, subjects with increases in BMI Z score of more than 1 SD during late childhood had a larger amount of adult subcutaneous adipose tissue (+83%; P < 0.001) than subjects with unchanged BMI Z score but an unaffected amount of visceral adipose tissue. BMI changes during adolescence predict both visceral and subcutaneous adipose tissue of the abdomen, whereas BMI changes during late childhood predict only the subcutaneous adipose tissue. CONCLUSIONS--The amount of visceral adipose tissue in young adult men was associated with BMI changes specifically during adolescence, whereas the amount of subcutaneous adipose tissue was associated with BMI changes during both late childhood and adolescence. Diabetes 58:867-874, 2009 [ABSTRACT FROM AUTHOR]

Abstract: In this work, we investigated a potential mechanism behind the observation of increased aminotransferase levels in a phase I clinical trial using a lipid-lowering drug, the peroxisome proliferator-activated receptor (PPAR) α agonist, AZD4619. In healthy volunteers treated with AZD4619, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were elevated without an increase in other markers for liver injury. These increases in serum aminotransferases have previously been reported in some patients receiving another PPARα agonist, fenofibrate. In subsequent in vitro studies, we observed increased expression of ALT1 protein and mRNA in human hepatocytes after treatment with fenofibric acid. The PPAR effect on ALT1 expression was shown to act through a direct transcriptional mechanism involving at least one PPAR response element (PPRE) in the proximal ALT1 promoter, while no effect of fenofibrate and AZD4619 was observed on the ALT2 promoter. Binding of PPARs to the PPRE located at −574 bp from the transcriptional start site was confirmed on both synthetic oligonucleotides and DNA in hepatocytes. These data show that intracellular ALT expression is regulated by PPAR agonists and that this mechanism might contribute to increased ALT activity in serum. [Copyright &y& Elsevier]

Interpretations: Our findings suggest that if oestrogen action is inhibited in growing adolescents, adult height will increase. This finding provides a rationale for studies that aim to delay bone maturation in several growth disorders. [ABSTRACT FROM AUTHOR]

Males with the 45,X/46,XY karyotype and malformations of the external genitalia carry an increased risk of developing germ cell neoplasia of the gonads. We have studied gonadal tissue from 10 individuals, 0.3–17 years of age, with a male phenotype and either hypospadias and/or cryptorchidism. Four patients, 0.3–15 years of age, had carcinoma in situ, 1 boy had Sertoli-cell-only pattern and the remainder prepubertal histology. Gonadoblastoma or invasive carcinoma was not found. On the basis of our current knowledge we propose a strategy for management and follow-up of these boys in order to detect possible premalignant histological changes early and prevent development of a gonadal tumour.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]