Carina Ankarberg-Lindgren

A specific aromatase inhibitor and potential increase in adult height in boys with delayed puberty: a randomised controlled trial

BACKGROUND The role of oestrogens in the closure of growth plates in both sexes is unequivocal. We postulated that inhibition of oestrogen synthesis in boys with delayed puberty would delay maturation of the growth plates and ultimately result in increased adult height. METHODS We did a randomised, double-blind, placebo-controlled study in which we treated boys with constitutional delay of puberty with testosterone and placebo, or testosterone and letrozole. Boys who decided to wait for the spontaneous progression of puberty without medical intervention composed the untreated group. FINDINGS Letrozole effectively inhibited oestrogen synthesis and delayed bone maturation. Progression of bone maturation was slower in the letrozole group than in the placebo group. In 18 months, bone age had advanced 1.1 (SD 0.8) years in the untreated group and 1.7 (0.9) years in the group treated with testosterone and placebo, but only 0.9 (0.6) years in the letrozole group (p=0.03 between the treatment groups). Predicted adult height did not change significantly in the untreated group and in the placebo group, whereas in the group treated with letrozole the increase was 5.1 (3.7) cm (p=0.004). 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.

Postmenopausal Hormone Replacement Therapy Modifies Skeletal Muscle Composition and Function: A Study with Monozygotic Twin Pairs

We investigated whether long-term hormone replacement therapy (HRT) is associated with mobility and lower limb muscle performance and composition in postmenopausal women. Fifteen 54- to 62-yr-old monozygotic female twin pairs discordant for HRT were recruited from the Finnish Twin Cohort. Habitual (HWS) and maximal (MWS) walking speeds over 10 m, thigh muscle composition, lower body muscle power assessed as vertical jumping height, and maximal isometric hand grip and knee extension strengths were measured. Intrapair differences (IPD%) with 95% confidence intervals (CI) were calculated. The mean duration of HRT use was 6.9 +/- 4.1 yr. MWS was on average 7% (0.9 to 13.1%, P = 0.019) and muscle power 16% (-0.8 to 32.8%, P = 0.023) greater in HRT users than in their cotwins. Thigh muscle cross-sectional area tended to be larger (IPD% = 6%, 95% CI: -0.07 to 12.1%, P = 0.065), relative muscle area greater (IPD% = 8%, CI: 0.8 to 15.0%, P = 0.047), and relative fat area smaller (IPD% = -5%, CI: -11.3 to 1.2%, P = 0.047) in HRT users than in their sisters. There were no significant differences in maximal isometric strengths or HWS between users and nonusers. Subgroup analyses revealed that estrogen-containing therapies (11 pairs) significantly decreased total body and thigh fat content, whereas tibolone (4 pairs) tended to increase muscle cross-sectional area. This study showed that long-term HRT was associated with better mobility, greater muscle power, and favorable body and muscle composition among 54- to 62-yr-old women. The results indicate that HRT is a potential agent in preventing muscle weakness and mobility limitation in older women.

Are Adolescent Boys with Klinefelter Syndrome Androgen Deficient? A Longitudinal Study of Finnish 47,XXY Boys

Testosterone (T)-substitution therapy is widely used in adult patients with Klinefelter syndrome (KS) to prevent symptoms and sequels of androgen deficiency, but it is currently unknown if adolescent boys with KS benefit from early T therapy. To evaluate the optimal age to start T substitution, we searched for signs of androgen deficiency in pubertal boys with KS. 14 nonmosaic 47,XXY boys, aged 10–13.9 y, were followed up for 4–37 mo with staging of puberty and frequent reproductive hormone measurements. Furthermore, indices reflecting androgen action (serum SHBG, leptin, and prostate-specific antigen (PSA) levels) were studied. Both onset and progression of puberty according to Tanner stages were normal in boys with KS. Consistently, serum T concentrations increased as expected and remained normal throughout follow-up. Changes in the indices of androgen action (decreases in serum SHBG and leptin, and increase in serum PSA concentrations) occurred normally, except that average leptin levels were higher in the boys with KS (KS boys 11.8 ± 7.0 μg/L; controls 7.6 ± 4.7 μg/L; p = 0.033). Despite normal T concentrations, the KS boys displayed from the age of 13 y elevated serum FSH and LH levels, and exaggerated gonadotropin responses to gonadotropin-releasing hormone. These data do not demonstrate an unequivocal androgen deficiency in adolescent boys with KS that would necessitate androgen supplementation therapy during early puberty.

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

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.

Differential influence of peripheral and systemic sex steroids on skeletal muscle quality in pre‐ and postmenopausal women

Aging is associated with gradual decline of skeletal muscle strength and mass often leading to diminished muscle quality. This phenomenon is known as sarcopenia and affects about 30% of the over 60‐year‐old population. Androgens act as anabolic agents regulating muscle mass and improving muscle performance. The role of female sex steroids as well as the ability of skeletal muscle tissue to locally produce sex steroids has been less extensively studied. We show that despite the extensive systemic deficit of sex steroid hormones in postmenopausal compared to premenopausal women, the hormone content of skeletal muscle does not follow the same trend. In contrast to the systemic levels, muscle tissue of post‐ and premenopausal women had similar concentrations of dehydroepiandrosterone and androstenedione, while the concentrations of estradiol and testosterone were significantly higher in muscle of the postmenopausal women. The presence of steroidogenetic enzymes in muscle tissue indicates that the elevated postmenopausal steroid levels in skeletal muscle are because of local steroidogenesis. The circulating sex steroids were associated with better muscle quality while the muscle concentrations reflected the amount of infiltrated fat within muscle tissue. We conclude that systemically delivered and peripherally produced sex steroids have distinct roles in the regulation of neuromuscular characteristics during aging.

Twenty-four hours secretion pattern of serum estradiol in healthy prepubertal and pubertal boys as determined by a validated ultra-sensitive extraction RIA

BackgroundThe 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.MethodsSixty-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.ResultsMean 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.ConclusionWith the use of an ultra-sensitive extraction RIA, we have provided clinically useful normative data for estradiol secretion in boys.

Elevated Serum Levels of Estradiol, Dihydrotestosterone, and Inhibin B in Adult Males Born Small for Gestational Age

CONTEXT Prenatal growth restriction may affect future fertility in both females and males. Studies have shown that growth-retarded male rats have different sexual behavior and disturbed steroidogenesis. OBJECTIVE We hypothesized that adult human males born small for gestational age (SGA) have an altered sex hormone profile. DESIGN, SETTING, AND PATIENTS Twenty-five adult males born SGA with median birth weight -2.2 sd scores (SDS) and birth length -2.4 SDS were studied. Median age was 23.1 yr and final height -0.5 SDS. They were compared with 44 male controls with median age 20.5 yr and final height 0.4 SDS. MAIN OUTCOME MEASURE The primary outcome before the study started was 17beta-estradiol (E(2)) levels in SGA males. RESULTS The SGA group showed significantly higher median levels of E(2), 17.9 pg/ml (P < 0.001), and dihydrotestosterone (DHT), 0.543 ng/ml (P < 0.05), compared with controls, 12.6 pg/ml and 0.423 ng/ml, respectively. Testosterone (T) levels did not differ between groups. E(2) to T ratio correlated negatively to birth weight (r = -0.40, P < 0.01) and birth length (r = -0.44, P < 0.001). DHT to T ratio correlated negatively to birth weight (r = -0.51, P < 0.001) and birth length (r = -0.38, P < 0.01). Males born SGA also had significantly higher median levels of inhibin B, 164 pg/ml (P < 0.05), compared with controls, 137 pg/ml. Inhibin B correlated negatively to birth length (r = -0.34, P < 0.01). CONCLUSION SGA males of normal stature have higher levels of E(2), DHT, and inhibin B than controls, indicating a disturbed steroid synthesis or metabolism. Aromatase activity, calculated as E(2) to T ratio, and 5alpha-reductase activity, calculated as DHT to T ratio, is negatively correlated to size at birth.

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

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-Müllerian 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.

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

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.

Sensitive RIA measures testosterone concentrations in prepubertal and pubertal children comparable to tandem mass spectrometry

Abstract 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.