| 1. |
- Albin, Anna-Karin, et al.
(författare)
-
Estradiol and Pubertal Growth in Girls.
- 2012
-
Ingår i: Hormone research in paediatrics. - : S. Karger AG. - 1663-2826 .- 1663-2818. ; 78:4
-
Tidskriftsartikel (refereegranskat)abstract
- 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, EC(50), 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.
|
|
| 2. |
- Albin, Anna-Karin, et al.
(författare)
-
Pubertal growth and serum testosterone and estradiol levels in boys.
- 2013
-
Ingår i: Hormone research in pædiatrics. - : S. Karger AG. - 1663-2826 .- 1663-2818. ; 80:2, s. 100-10
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 3. |
|
|
| 4. |
- Ankarberg-Lindgren, Carina, 1963, et al.
(författare)
-
A purification step prior to commercial sensitive immunoassay is necessary to achieve clinical usefulness when quantifying serum 17beta-estradiol in prepubertal children
- 2008
-
Ingår i: European Journal of Endocrinology. - 1479-683X. ; 158:1, s. 117-24
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To test the clinical usefulness of sensitive commercial immunoassays for determination of low 17beta-estradiol concentrations in children. METHODS: The lower limit of detection and clinical usefulness (functional sensitivity) of three commercial estradiol immunoassays were validated by use of 500 sera from prepubertal and pubertal children and 55 pooled sera. The three immunoassays consisted of two modified direct immunoassays; one RIA (Spectria Estradiol RIA) and one time-resolved fluoroimmunoassay (AutoDELFIA Estradiol), both with increased serum volume in relation to antibody concentration and extended incubation time. In the third method, serum was purified and concentrated using diethyl ether extraction prior to measurement by the modified Spectria Estradiol RIA. RESULTS: The lower limits of detection and clinical usefulness were 9 and 30 pmol/l for the direct RIA, 11 and 50 pmol/l for the AutoDELFIA, and 4 and 6 pmol/l for serum determined by extraction RIA. When measuring the serum pool originating from girls at breast stages 1-2, the direct RIA and AutoDELFIA resulted in significantly higher 17beta-estradiol concentrations when compared with the extraction RIA (+58 and +267%, P<0.001). We found a significant difference in 17beta-estradiol concentrations between girls at breast stages 1 (median 6 pmol/l) and 2 (median 16 pmol/l), when quantified by the extraction RIA (P<0.0001) but no difference when quantified with the direct RIA (median values 12 and 14 pmol/l respectively). CONCLUSION: For determination of low serum 17beta-estradiol concentrations in children, an extraction step prior to commercial immunoassay is needed to achieve clinically useful results.
|
|
| 5. |
|
|
| 6. |
- Ankarberg-Lindgren, Carina, 1963, et al.
(författare)
-
Changes of diurnal rhythm and levels of total and free testosterone secretion from pre to late puberty in boys: testis size of 3 ml is a transition stage to puberty
- 2004
-
Ingår i: Eur J Endocrinol. ; 151:6, s. 747-57
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To establish levels for comparison for 24-h total and free serum testosterone in prepubertal boys and throughout pubertal development. DESIGN: The study subjects were 55 healthy boys, aged 5.0-18.6 years, who underwent serial sampling one or more times during their pubertal development. METHODS: Testicular volumes were determined by orchidometer. Serum testosterone was measured by a modified RIA (detection limit, 0.03 nmol/l). Free testosterone was calculated (calc-FT) using a formula derived from the law of mass action. RESULTS: Significant increases in testosterone and calc-FT concentrations in boys were found between testis volumes of 1 ml to 2 ml, 2 ml to 3 ml, 6 ml to 8 ml, and 10 ml to 15 ml. No differences were found between testis volumes of 3, 4, 5 and 6 ml neither were there differences between 8 and 10 ml, or between 15, 20 and 25 ml. Boys who had reached their final height had higher calc-FT values than boys who had the same pubertal development but had not reached their final height. Based on the results, puberty was classified into six stages: pre1 (testis, 1 ml), pre2 (testis, 2 ml), early (testis, 3-6 ml), mid (testis, 8-12 ml), late1 (testis,15-25 ml, not reached final height) and late2 (testis, 15-25 ml, reached final height). Serum testosterone was secreted with a diurnal variation in prepuberty and during puberty. The increase of testosterone in the morning hours started earlier in pubertal than in pre-pubertal boys. The most pronounced diurnal rhythm was found in early and in mid puberty. CONCLUSION: Using a sensitive method, and a pubertal reclassification, we have established levels for comparison of testosterone and calc-FT in prepubertal and pubertal boys. The existence of data for comparison forms the basis for future studies on pubertal disorders.
|
|
| 7. |
- Ankarberg-Lindgren, Carina, 1963, et al.
(författare)
-
Diurnal rhythm of testosterone secretion before and throughout puberty in healthy girls: correlation with 17beta-estradiol and dehydroepiandrosterone sulfate.
- 1999
-
Ingår i: The Journal of clinical endocrinology and metabolism. - 0021-972X. ; 84:3, s. 975-84
-
Tidskriftsartikel (refereegranskat)abstract
- The regulation of androgen synthesis during puberty in females is complicated, with changes in steroidogenic and peripheral interconversion capacity. In the present study we have investigated the diurnal rhythm of testosterone secretion in 56 healthy girls before and during puberty, up to 2 yr postmenarche. The girls' ages ranged between 4.6-16.5 yr, and their height SD scores ranged between -3.6 and +3.7. One to 5 serum profiles (seven samples per 24 h) were taken from each girl for steroid measurements, and a total of 84 serum profiles were obtained. Serum testosterone concentrations were determined using a RIA with a detection limit of 30 pmol/L. The results demonstrate that there is a diurnal rhythm of testosterone secretion during both prepuberty and puberty in girls. The pattern has its nadir in the late evening or just after midnight, with the highest levels in the morning (0600-1000 h). Serum testosterone concentrations in prepubertal girls were significantly lower than those in pubertal girls and were significantly lower in early puberty than in girls in mid- or late puberty. No differences were found in levels between girls in midpuberty or late puberty. Before puberty, serum testosterone concentrations correlated with serum dehydroepiandrosterone sulfate, consistent with the adrenals being the major source of testosterone. After the onset of puberty, a correlation between testosterone and 17beta-estradiol was seen, consistent with the ovaries being the major source of testosterone during puberty. Furthermore, the present study showed that there is a relative hyperandrogenicity in early puberty, with high levels of androgens relative to estrogens.
|
|
| 8. |
- Ankarberg-Lindgren, Carina, 1963, et al.
(författare)
-
Estradiol in pediatric endocrinology
- 2009
-
Ingår i: American Journal of Clininical Pathology. - 1943-7722. ; 132:6, s. 978-80
-
Tidskriftsartikel (refereegranskat)
|
|
| 9. |
- Ankarberg-Lindgren, Carina, 1963, et al.
(författare)
-
Leptin levels show diurnal variation throughout puberty in healthy children, and follow a gender-specific pattern
- 2001
-
Ingår i: Eur J Endocrinol. ; 145:1, s. 43-51
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the levels and diurnal rhythm of serum leptin in healthy children, and to investigate the association between leptin levels and sex steroids. METHODS: Four girls and four boys, all healthy volunteers, were followed longitudinally throughout puberty. Their chronological ages ranged from 8.7 to 19.5 years, and body composition, expressed as weight-for-height standard deviation scores (SDS), ranged between -1.7 and +2.4. Serum leptin, oestradiol and testosterone concentrations were measured by radioimmunoassay at 1000, 1400, 1800, 2200, 0200 and 0600 h. RESULTS: In all girls and boys, both prepubertally and during pubertal development, serum leptin levels increased during the night, with no difference in relative peak amplitude. In boys, the leptin concentrations increased until the initiation of puberty and then declined, whereas in girls, the concentrations increased throughout puberty. The inter-individual variation in mean leptin levels among girls decreased to 11% at the time of menarche. A positive correlation was found for both oestradiol and testosterone versus leptin in girls throughout puberty (r=0.64 and r=0.71 respectively, P<0.001). A negative correlation was found between leptin and testosterone in boys in mid- and late puberty (r=-0.66, P<0.01). No correlation was found between oestradiol and leptin in boys or between testosterone and leptin in pre- and early pubertal boys. CONCLUSION: Serum leptin concentrations show diurnal variation throughout pubertal development in both girls and boys. The changes in leptin levels during puberty follow a gender-specific pattern, probably due to an influence of sex steroids on leptin production.
|
|
| 10. |
|
|
