Use of Gonadotropin-Releasing Hormone Analogs in Children: Update by an International Consortium.

This update, written by authors designated by multiple pediatric endocrinology societies (see List of Participating Societies) from around the globe, concisely addresses topics related to changes in GnRHa usage in children and adolescents over the last decade. Topics related to the use of GnRHa in precocious puberty include diagnostic criteria, globally available formulations, considerations of benefit of treatment, monitoring of therapy, adverse events, and long-term outcome data. Additional sections review use in transgender individuals and other pediatric endocrine related conditions. Although there have been many significant changes in GnRHa usage, there is a definite paucity of evidence-based publications to support them. Therefore, this paper is explicitly not intended to evaluate what is recommended in terms of the best use of GnRHa, based on evidence and expert opinion, but rather to describe how these drugs are used, irrespective of any qualitative evaluation. Thus, this paper should be considered a narrative review on GnRHa utilization in precocious puberty and other clinical situations. These changes are reviewed not only to point out deficiencies in the literature but also to stimulate future studies and publications in this area.

Body mass index in girls with idiopathic central precocious puberty during and after treatment with GnRH analogues.

BACKGROUND: In girls with Idiopathic Central Precocious Puberty (ICPP) concern has been raised by the potential impact of GnRH-analogues (GnRHa) treatment on body weight. We evaluated the effect of GnRHa on Body Mass Index (BMI) in girls with ICPP according to weight status at diagnosis. METHODS: One hundred seventeen ICPP girls were divided according to pretreatment weight status in: normal weight (NW), overweight (OW) and obese (OB). BMI at one and two years of treatment was assessed. BMI-SDS of 60 patients who reached adult height (AH) was compared to that of 33 ICPP untreated girls. RESULTS: NW girls significantly increased their baseline BMI-SDS at 1 and 2 years of treatment. OW girls only had a significant increment at one year of treatment while OB girls showed no BMI-SDS change. Patients evaluated at AH (at least four years after GnRHa withdrawal) showed a significant decrease on BMI compared to baseline and a significantly lower BMI than the untreated group. CONCLUSION: In ICPP girls the BMI increase under GnRHa was inversely related to the pretreatment weight status. In the long term follow-up, no detrimental effect of GnRHa on body weight was observed. BMI-SDS was lower in treated than in untreated girls.

Early onset of primary hypogonadism revealed by serum anti-Müllerian hormone determination during infancy and childhood in trisomy 21.

Male patients with an extra sex chromosome or autosome are expected to present primary hypogonadism at puberty owing to meiotic germ-cell failure. Scarce information is available on trisomy 21, a frequent autosomal aneuploidy. Our objective was to assess whether trisomy 21 presents with pubertal-onset, germ-cell specific, primary hypogonadism in males, or whether the hypogonadism is established earlier and affects other testicular cell populations. We assessed the functional status of the pituitary-testicular axis, especially Sertoli cell function, in 117 boys with trisomy 21 (ages: 2months-20year). To compare with an adequate control population, we established reference levels for serum anti-Müllerian hormone (AMH) in 421 normal males, from birth to adulthood, using a recently developed ultrasensitive assay. In trisomy 21, AMH was lower than normal, indicating Sertoli cell dysfunction, from early infancy, independently of the existence of cryptorchidism. The overall prevalence rate of AMH below the 3rd percentile was 64.3% in infants with trisomy 21. Follicle-stimulating hormone was elevated in patients <6months and after pubertal onset. Testosterone was within the normal range, but luteinizing hormone was elevated in most patients <6months and after pubertal onset, indicating a mild Leydig cell dysfunction. We conclude that in trisomy 21, primary hypogonadism involves a combined dysfunction of Sertoli and Leydig cells, which can be observed independently of cryptorchidism soon after birth, thus prompting the search for new hypotheses to explain the pathophysiology of gonadal dysfunction in autosomal trisomy.

La determinación de PTH intraquirúrgica o posquirúrgica por quimioluminiscencia predice la hipocalcemia en el posoperatorio de la tiroidectomía en niños / Determination of PTH during or post surgery for quimioluminiscency can predict hypocalcemy in the post surgery children´s thyroidectomy

Objetivo: Evaluar la eficacia diagnóstica de la determinación de PTH en muestras de plasma tomadas durante la cirugía (intra) y posquirúrgica inmediata para predecir el riesgo de desarrollar hipocalcemia en el postoperatorio de la tiroidectomía total en pacientes pediátricos. Métodos: Se llevó a cabo un estudio de cohortes,prospectivo, longitudinal con 20 pacientes pediátricos en los que se practicó tiroidectomía total. Se determinaron los niveles de PTH preoperatorios, intraoperatorios y en el período posquirúrgico inmediato (basal, 5 y 60 minutos de la remoción de la glándula tiroides) utilizando un ensayo automatizado quimioluminiscente (IMMULITE, Siemens), límite de cuantificación 8 pg/mL, CV intra e interensayos < 5,4%. Para este estudio, la concentración de PTH de cada paciente no fue conocida por el equipo tratante hasta el final del mismo. Además se determinó la concentración en suero de Calcio total (Ca T) y/o Calcio iónico (Cai) regularmente durante las 48 hs posquirúrgicas y se controló la presencia de síntomas o signos de hipocalcemia. Se consideró hipocalcemia Ca T < 8 mg/dl y/o Cai < 0,8 nmol/L. Se realizó un análisis por curva ROC para determinar el nivel de PTH que fuera más eficaz en predecir la aparición de hipocalcemia según su sensibilidad (S), especificidad (E), eficiencia diagnóstica (ED) y Valor Predictivo Positivo (VPP). Resultados: Diez de los 20 pacientes (50%) desarrollaron hipocalcemia y 3 de ellos presentaron síntomas. La presentación de hipocalcemia sucedió: 40% en las primeras 6 hs y 40% a las 24 hs.vel de PTH en la muestra intraoperatoria < 14 pg/ml mostró S: 80%, E: 100%, ED: 90% (IC95%: 73-100) y VPP: 100% para predecir hipocalcemia posquirúrgica. En la muestra posquirúrgica inmediata, la concentración de PTH < 14 pg/ml presentó S: 80%, E: 90%, ED 82% (IC95% 63-100) y VPP 90% para predecir hipocalcemia posquirúrgica. Cuando la PTH intraquirúrgica o posquirúrgica es <14 pg/ml el riesgo relativo de presentar hipocalcemia postiroidectomía es de 9. Conclusiones: La medición de PTH intraquirúrgica y posquirúrgica es una herramienta eficiente para predecir hipocalcemia posquirúrgica por tiroidectomía total en la población pediátrica. Esta detección permite la inmediata decisión sobre el tratamiento suplementario con calcio en los pacientes de riesgo mejorando su evolución y evitando la presentación de tetania y otros síntomas de hipocalcemia. Además, permitiría disminuir los controles en los pacientes que evolucionarán con normocalcemia, reduciendo en ambos grupos de pacientes los costos de internación.

Alteraciones neuroendocrinas del síndrome de poliquistosis ovárica en la adolescencia / Neuroendrocrine anormalities in adolescents with polycystiz ovary sindrome

El síndrome de poliquistosis ovárica (SPCO) es una de las endocrinopatías más comunes que afecta a las mujeres en edad reproductiva, su expresión clínica comienza en edad perimenárquica y si bien fue descripto hace más de 70 años, hasta el presente, el(los) mecanismo(s) fisiopatológico(s) que lo origina(n) no se conoce(n) con certeza. Debido a la gran heterogeneidad en la expresión clínica y bioquímica que caracteriza al SPCO es probable que existan subgrupos de pacientes en las que sea posible identificar alguno de los mecanismos implicados en la patogenia como el responsable de los principales signos y síntomas observados. La presente revisión propone conocer en profundidad las anormalidades neuroendocrinas como uno de los principales componentes del síndrome. En nuestra experiencia, las adolescentes con SPCO presentan hipersecreción de LH (aumento de la masa de LH secretada por pulso, de la frecuencia de pulsos y de la tasa de producción), y un patrón desordenado de secreción de LH (mayores valores de ApEn) en relación a adolescentes eumenorreicas. Varias líneas de evidencia sugieren que uno de los mecanismos responsables de estos defectos es el aumento de frecuencia de secreción del GnRH. Las adolescentes con SPCO secretan moléculas de LH con mayor actividad biológica y mayor proporción de isoformas con punto isoeléctrico más alcalino que las adolescentes eumenorreicas. La preponderancia de isoformas más básicas y más bioactivas en estas pacientes se relaciona con elevados niveles séricos de 17-hidroxiprogesterona, androstenodiona (A) y testosterona (T). El aumento de la frecuencia de pulsos de GnRH y un microambiente hormonal caracterizado por exceso de andrógenos podrían conjuntamente promover la predominante secreción de este tipo de isoformas de LH. En ausencia de obesidad, las pacientes con SPCO presentan un incremento de la tasa de producción de GH y un patrón de secreción más ordenado (menores valores de ApEn, similar al patrón de secreción de GH observado en el varón adulto). La mayor secreción de GH podría potenciar la acción gonadotrófica sobre la esteroideogénesis ovárica. Analizando la sincronía entre pares de hormonas relacionadas mediante dos técnicas complementarias (cross ApEn y cross correlación) se demuestra que las adolescentes con SPCO presentan un deterioro en las asociaciones entre LH-andrógenos comparadas con las adolescentes eumenorreicas. El desacople de la secreción bihormonal (LH-A y LH-T) en adolescentes con SPCO es consistente con defectos en el control de la secreción ovárica de andrógenos dependiente de LH y con una alteración en el control negativo que ejercen los andrógenos sobre la secreción GnRH/LH. Estas alteraciones neuroendocrinas en la unidad GnRH/LH y andrógenos ováricos podrían promover el hiperandrogenismo y alterar la maduración folicular.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women in reproductive age, frequently begins during adolescence causing menstrual irregularity and hirsutism. Although described up more than seventy years ago, the primary pathophysiologic mechanisms underlying this disorder remain unknown.There is not a single etiologic factor that fully accounts for the spectrum of abnormalities in the PCOS. This review addresses current knowledge about the neuroendocrine abnormalities as a major component of the syndrome. From this perspective, adolescents with PCOS exhibit an accelerated frequency and/or higher amplitude of LH pulses, augmentation of secretory burst mass, and a more disorderly LH release (higher ApEn) than eumenorrheic adolescents. Several lines of evidence suggest that the mechanisms underlying the defects in LH secretion in PCOS include an increased frequency of GnRH secretion. These patients also show elevated in vitro LH bioactivity and a preponderance of basic LH isoforms, which correlate positively with elevated serum of 17-hydroxyprogesterone, androstenedione (A), and testosterone (T) concentrations. Heightened GnRH drive of gonadotropin secretion and steroid-permissive milieu appear to jointly promote elevated secretion of basic LH isoforms. Non obese adolescents with PCOS secrete GH at a higher rate and with more orderly patterns (resembling a male profile) than controls. Indeed, GH appears to act as a co-gonadotropin. When synchronicity of paired hormone profiles was appraised by two independent, but complementary, statistical tools (cross-entropy and cross correlation), concomitant uncoupling of the pairwise synchrony of LH - androgens was demonstrated in girls with PCOS. Asynchrony of LH-A and LH-T pairs further localizes a pathway defect to LH-dependent feedforward control of ovarian androgen secretion. These abnormalities are also consistent with altered androgen negative feed-back regulation of GnRH/LH output. These data suggest that in PCOS there are anomalies of signaling between GnRH/LH and ovarian androgens that promote hiperandrogenism and impaired follicle maturation.

Características clínicas, endocrinas y metabólicas de una población argentina de niñas con pubarca prematura / Clinical, hormonal and metabolic findings in argentinean girls with premature pubarche

La pubarca prematura se ha asociado con alteraciones hormonales y metabólicas. Se estudiaron 40 niñas con pubarca prematura de 7,23 ± 0,29 años (media ± ESM). Se evaluó grado de desarrollo, talla, edad ósea, IMC y peso al nacimiento (PN). Se dosaron andrógenos, gonadotrofinas, lípidos, glucemia e insulina, HOMA e índice glucemia/insulina (G/I) y se compararon con un grupo control normal de 25 niñas. Las pacientes se dividieron según el nivel de sulfato de dehidroepiandrosterona (SDHEA) en dos grupos, Pre A (Pre adrenarca), < 400 ng/ml, n= 17 y Post A (Post adrenarca) < 400 ng/ml , n= 23. El grupo Post A tuvo mayor edad cronológica, edad ósea y grado de vello pubiano que el Pre A, sin diferencias en IMC ni en peso de nacimiento (PN). Insulina y HOMA fueron mayores y G/I menor en Post A que en Pre A y grupo control. Dos niñas en Post A tuvieron franca resistencia a la insulina. 64 % de las niñas en Pre A y 59 % en Post A tuvieron valores elevados o limítrofes de colesterol total (CT). Conclusiones: el grupo Post A presentó menor sensibilidad insulínica y ambos grupos de pacientes tuvieron valores de CT elevados, alteraciones que podrían favorecer el riesgo de futuras complicaciones. Se recomienda el seguimiento a largo plazo de todas las niñas con pubarca prematura.

Precocious pubarche in girls is caused by premature adrenarche in most cases. Less frequently it occurs in absence of biochemical markers of adrenarche being ascribed to increased target tissue sensitivity. Premature pubarche with pronounced adrenarche has been associated with insulin resistance and dyslipemia, especially in girls with history of low birth weight. Most studies have been conducted in hispanic and affrican-american patients. We studied a total of 40 argentinean girls with isolated premature pubarche, aged 7.23 ± 0.29 years (mean ± SEM) at the moment of diagnosis. Grade of sexual development, height, weight, BMI and birth weight (BW) were recorded. Dehidroepiandrosterone sulphate (DHEAS), androstenedione (A), testosterone (T), 17OH progesterone (17 OHP), SHBG, LH, FSH, PRL and estradiol were measured. Total cholesterol (TC), LDL cholesterol (LDL- C), triglycerides (TGC), glucose, insulin, HOMA and fasting glucose/ insulin index (G/I) were evaluated and compared with those in a control group of 25 normal girls. Patients were divided into two groups: Pre A (Pre adrenarche), with DHEAS < 400 ng/ml, and Post A (Post adrenarche), with DHEAS > 400 ng/ml. Post A girls had higher chronological age, bone age advancement and grade of pubic hair development than Pre A girls. No difference was found regarding BMI or BW. Besides higher DHEAS levels, Post A girls showed elevated A and 17OHP levels than Pre A girls (86 ± 8 vs 35 ± 4 ng/dl, p<0. 0001 and 1.1 ± 0.09 vs 0.75 ± 0.07 ng/ml, p< 0.01, respectively). Insulin levels (µUI/ml) were 4.51 ± 0.75 in Pre A, 6.53 ± 1.11 in Post A and 4.05 ± 0.45 in control group. Fasting G/I was 24.07 ± 3.75 in Pre A , 18.4 ± 2.34 in Post A and 25.41 ± 2.31 in controls. HOMA was 0.90 ± 0.12 in Pre A, 1.35 ± 0.22 in Post A and 0.89 ± 0.11 in control group. Post A girls had higher insulin and HOMA and lower G/I than control group girls (p<0.05) while those parameters in Pre A girls were not different than in normal control subjects. Only two patients in Post A group had HOMA and G/I consistent with insulin resistance. TC was higher in Pre A than in control group (182.2 ± 4.9 vs156.7 ± 8.5 mg/dl, p<0.05). According to The National Cholesterol Education Program definition, 64 % of Pre A girls and 59 % of Post A girls had elevated or borderline TC levels. TGC values were not different among Pre A, Post A and control group (81.1 ±7.1, 77.6 ± 6.1 and 71.9 ± 4.7 mg/dl, respectively. Summary and Conclusions: In this cohort of argentinean girls with premature pubarche, we did not find a significant history of intrauterine growth retardation. Patients with biochemical pattern of adrenarche showed clinical signs of androgen exposure (accelerated bone age, more advanced degree of pubic hair development) and a serum profile suggestive of reduced insulin sensitivity compared with those without biochemical adrenarche. Both groups of patients had undesirable total cholesterol levels. These findings support the recommendation of long-term follow-up for all girls with premature pubarche.

Disruption of the synchronous secretion of leptin, LH, and ovarian androgens in nonobese adolescents with the polycystic ovarian syndrome.

The present study probes putative disruption of hypothalamic control of multihormone outflow in polycystic ovarian syndrome by quantitating the joint synchrony of leptin and LH release in adolescents with this syndrome and eumenorrheic controls. To this end, hyperandrogenemic oligo- or anovulatory patients with polycystic ovarian syndrome (n = 11) and healthy girls (n = 9) underwent overnight blood sampling every 20 min for 12 h to monitor simultaneous secretion of leptin (immuno-radiometric assay), LH (immunofluorometry), and androstenedione and T (RIA). Synchronicity of paired leptin-LH, leptin-androstenedione, and leptin-T profiles was appraised by two independent bivariate statistics; viz., lag-specific cross-correlation analysis and pattern-sensitive cross-approximate entropy. The study groups were comparable in chronological and postmenarchal age, body mass index, fasting plasma insulin/glucose ratios, and serum E2 concentrations. Overnight mean (+/- SEM) serum leptin concentrations were not distinguishable in the two study groups at 30 +/- 4.8 (polycystic ovarian syndrome) and 32 +/- 7.4 microg/liter (control). Serum LH concentrations were elevated at 9.5 +/- 1.4 in girls with polycystic ovarian syndrome vs. 2.8 +/- 0.36 IU/liter in healthy subjects (P = 0.0015), androstenedione at 2.8 +/- 0.30 (polycystic ovarian syndrome) vs. 1.2 +/- 0.11 ng/ml (control) (P = 0.0002), and T at 1.56 +/- 0.29 (polycystic ovarian syndrome) vs. 0.42 +/- 0.06 ng/ml (P < 0.0001). Cross-correlation analysis shows that healthy adolescents maintained a positive relationship between leptin and LH release, wherein the latter lagged by 20 min (P < 0.01). No such association emerged in girls with polycystic ovarian syndrome. In eumenorrheic volunteers, leptin and androstenedione concentrations also covaried in a lag-specific manner (0.0001 < P < 0.01), but this linkage was disrupted in patients with polycystic ovarian syndrome. Anovulatory adolescents further failed to sustain normal time-lagged coupling between leptin and T (P < 0.01). Approximate entropy calculations revealed erosion of orderly patterns of leptin release in polycystic ovarian syndrome (P = 0.012 vs. control). Cross-entropy analysis of two-hormone pattern regularity disclosed marked disruption of leptin and LH (P = 0.0099), androstenedione and leptin (P = 0.0075) and T-leptin (P = 0.019) synchrony in girls with polycystic ovarian syndrome. In summary, hyperandrogenemic nonobese adolescents with oligo- or anovulatory polycystic ovarian syndrome manifest: 1) abrogation of the regularity of monohormonal leptin secretory patterns, despite normal mean serum leptin concentrations; 2) loss of the bihormonal synchrony between leptin and LH release; and 3) attenuation of coordinate leptin and androstenedione as well as leptin and T output. In ensemble, polycystic ovarian syndrome pathophysiology in lean adolescents is marked by vivid impairment of the synchronous outflow of leptin, LH and androgens. Whether analogous disruption of leptin-gonadal axis integration is ameliorated by therapy and/or persists into adulthood is not known.

Disruption of the joint synchrony of luteinizing hormone, testosterone, and androstenedione secretion in adolescents with polycystic ovarian syndrome.

The present study explores the postulate that the polycystic ovarian syndrome (PCOS) is marked by failure of physiological feedforward and feedback signaling between pituitary LH and ovarian androgens. To this end, we appraised the 3-fold simultaneous overnight release of LH (assayed by high precision immunofluorometry), testosterone (RIA), and androstenedione (RIA) in 12 an- or oligoovulatory adolescents with PCOS (mean +/- SEM age, 16.4 +/- 0.47 yr) and 10 eumenorrheic girls (age, 16.5 +/- 0.45 yr). Gynecological (postmenarchal) ages (years) were also comparable at 4.8 +/- 0.39 (PCOS) and 4.0 +/- 3.6 (control; P = NS). Body mass index and fasting serum insulin and estradiol concentrations were indistinguishable in the two study cohorts. Mean overnight serum concentrations of LH (assayed by both immunofluorometry and Leydig cell bioassay), testosterone, androstenedione, and 17alpha-hydroxyprogesterone were each elevated significantly in patients with PCOS (all P

Estrogen priming effect on growth hormone (GH) provocative test: a useful tool for the diagnosis of GH deficiency.

We have studied the effect of estradiol (E2) on the GH-insulin-like growth factor (GH-IGF) axis in 15 prepubertal GH deficiency (GHD) children and 44 prepubertal or early pubertal children with idiopathic short stature (SS). All of them received a daily dose of micronized E2 (1 or 2 mg) or placebo, for 3 days, before a sequential arginine-clonidine test. In SS children, GH maximal responses were 17.8+/-10.9 on placebo and 27.9+/-14.5 microg/L on estrogen (P < 0.0001). The lower 95% confidence limits for GH maximal response changed from 3.7 microg/L (without E2) to 8.3 microg/L (on E2). In GHD children, no significant stimulatory effect of estrogen on GH levels was observed. After placebo, a cut-off limit of 3.7 microg/L (the lower 95% confidence interval limit) resulted in 73% sensitivity, 95% specificity, and an overall 90% diagnostic efficiency. After E2, a cut-off limit of 8.3 microg/L resulted in a sensitivity of 87%, a specificity of 98%, and a diagnostic efficiency of 95%. After placebo, 68% of SS showed normal IGF-I levels, and the mean did not change on E2 (13.7+/-6.3 vs. 14.3+/-6.8 nmol/L, not significant). In 93% of SS, IGF binding protein (IGFBP)-3 levels were normal during placebo. On E2, mean IGFBP-3 did not change (2.63+/-0.70 vs. 2.70+/-0.70 mg/L, not significant). In 14 of 15 GHD patients, IGF-I values were below normal on placebo, and the mean of the group did not change after E2. During placebo, 13 of 15 GHD children presented low IGFBP-3 values. During E2, there was a small significant increase in IGFBP-3 values (1.06+/-0.58 vs. 1.20+/-0.69 mg/L, P < 0.02). The highest diagnostic efficiencies for IGF-I and IGFBP-3 were observed during placebo (75% and 91%, respectively). We conclude that GH stimulation tests after E2 priming had the highest diagnostic efficiency. Our findings suggest that the effect of estrogen priming on GH stimulated levels, by reducing the number of false nonresponders, might be useful to better discriminate between normal and abnormal GH status in SS children.

A preponderance of basic luteinizing hormone (LH) isoforms accompanies inappropriate hypersecretion of both basal and pulsatile LH in adolescents with polycystic ovarian syndrome.

We recently demonstrated that adolescent girls with polycystic ovarian syndrome (PCOS) exhibit augmented LH secretion due to an increase in immunofluorometric and deconvolution-estimated LH secretory burst mass and pulse frequency. Concurrently, we inferred either a prolongation of apparent (endogenous) LH half-life or elevated basal (nonpulsatile) LH release in PCOS. The in vivo half-life of LH molecules can be affected by the oligosaccharide side-chains, which also modify in vitro bioactivity and electrostatic change. Accordingly, as a surrogate estimator of altered endogenous LH half-life and/or biopotency in PCOS, we characterized the isoelectric properties of secreted LH isoforms and determined their in vitro biological activity in adolescent girls with PCOS compared with healthy age-matched eumenorrheic controls. To this end, 12-h (overnight) serum samples from PCOS patients (n = 12) and normal adolescents (n = 10) were pooled by subject. Bioactive LH concentrations were then quantitated in a rat Leydig cell in vitro bioassay, and immunological activity was determined by immunofluorometry. The distribution of LH isoforms was evaluated by preparative chromatofocusing (pH window, 10.5 to <4.0) of samples further combined to yield three independent serum pools for each of the patient and control groups. Fasting serum concentrations of 17-hydroxyprogesterone (17-OHP), androstenedione, testosterone, estrone, estradiol, and sex hormone-binding globulin were determined as possible endocrine correlates of LH isotypes. Mean serum concentrations of immunoreactive and bioactive LH in adolescents with PCOS were 3 and 2 times higher than values in controls: immunoreactive: PCOS, 7.8+/-0.9; controls: 2.6+/-0.3 IU/L (P < 0.001); and bioactive: PCOS, 52+/-10; controls, 25+/-4.1 IU/L (P = 0.002), respectively. Bioactive LH concentrations correlated positively with 17-OHP (P = 0.022), androstenedione (P = 0.012), and testosterone (P = 0.046) concentrations in PCOS. Chromatofocusing of LH isoforms disclosed greater LH immunoreactivity at pI values greater than 8 and 7.99-7.0 in adolescents with PCOS compared with controls (P = 0.031). The percentage of basic LH isoforms was related positively to serum concentrations of 17-OHP (P = 0.032), androstenedione (P = 0.046), and testosterone (P = 0.040). In conclusion, the present isotype analysis demonstrates elevated in vitro LH bioactivity and a preponderance of basic LH isoforms in girls with PCOS. Since previously reported heterologous in vivo assays of LH kinetics point toward accelerated removal of such alkaline isotypes, our findings would favor the earlier alternative hypothesis of inappropriate hypersecretion of basal (interpulse) LH rather than prolongation of the LH half-life as the mechanism for elevated interpulse serum LH concentrations in adolescents with PCOS. In ensemble, the foregoing data thus suggest 3-fold amplification of basal LH secretion as well as both a heightened amplitude and frequency of the pulsatile mode of LH release in PCOS.

Thyroid profile modifications during oral hormone replacement therapy in postmenopausal women.

There are few data available about changes in thyroid hormone profiles after hormone replacement therapy (HRT). We analyzed the effect of two different oral estrogens/progestins (E/P) associations on thyroid hormones and thyroxine-binding globulin (TBG) levels in 14 postmenopausal normal women distributed at random into two groups. Both groups received daily for a year 2 mg of estradiol valeriante per os. In Group A (n = 7), estrogen was associated with norethisterone acetate. In Group B, estrogen was associated with promegestone in a similar schedule to Group A. Blood samples were withdrawn to measure estradiol (E2), thyroxine (T4), triiodothyronine (T3), free T4 (fT4), thyroid-stimulating hormone (TSH) and TBG before and after 3, 6 and 12 months of treatment. Estradiol level increased significantly in both groups, being higher in Group A than in B. Under therapy, T4 and TBG levels were increased in both groups, but within the normal range. T4 mean level increased by 34% in Group A and 20% in Group B. TBG increment was slightly significant for Group A (p < 0.02); with only a trend in Group B (p = 0.08). T3, fT4 and TSH levels did not change significantly and remained within the normal range. Oral therapy with associated E/P produces moderate increases in T4 and TBG levels. Our results suggest that in postmenopausal women on oral HRT, fT4 and TSH levels are the most useful tools to evaluate the thyroid axis status.

Augmented frequency and mass of LH discharged per burst are accompanied by marked disorderliness of LH secretion in adolescents with polycystic ovary syndrome.

The aim of this study was to quantify pulsatile LH secretion, burst frequency and mass, LH half-life, and the approximate entropy (ApEn) or (dis-) orderliness of LH release in adolescents with polycystic ovary syndrome (PCOS), combining a high-precision immunofluorimetric LH assay with deconvolution techniques. We sampled LH concentration profiles every 20 min overnight in 12 girls with PCOS (mean +/- S.E.M. age 16.4+/-0.57 years, body mass index (BMI) 24.4+/-1.6 kg/m2) and 11 eumenorrheic early-follicular-phase controls (mean +/- S.E.M. age 16.5+/-0.47 years, BMI 22.2+/-1.0 kg/m2). Fasting serum levels of androstenedione, testosterone, 17-hydroxyprogesterone (17-OHP), estrone, estradiol, FSH and sex hormone-binding globulin (SHBG) were determined. Compared with euandrogenic girls, PCOS adolescents had significantly (P<0.005) elevated serum LH/FSH ratios, 17-OHP, androstenedione, esterone and testosterone levels, decreased SHBG, and similar estradiol. PCOS subjects exhibited a 3-fold higher mean serum LH concentration with almost no overlap with controls (8.8+/-1.2 and 2.8+/-0.3 IU/l respectively, P<0.001). We initially used a conventional serum hormone concentration peak analysis method (Cluster) to evaluate the characteristics of pulsatile LH release. Cluster analysis disclosed a significant increase in serum LH concentration maximal peak height, a higher LH peak frequency and a higher mean serum LH concentration in interpulse nadirs in the PCOS group. Deconvolution analysis of mechanisms underlying the foregoing showed higher frequency in the PCOS group than the controls (7.9+/-0.4 and 5.7+/-0.6 pulses/12 h respectively, P<0.05). The mass of LH released per secretory event was also significantly higher in PCOS subjects than controls (5.4+/-0.57 and 3.4+/-0.56 IU/l respectively, P<0.05). Since the pulsatile production rate is the product of the mean mass of hormone secreted per pulse and the number of pulses per day, we estimated a significantly higher mean pulsatile production rate of (endogenous) LH in the PCOS group (41+/-4.2 IU/l per day in the PCOS group vs 18+/-2.3 IU/l per day in the controls, P<0.01). The mean estimated half-life of endogenous LH disappearance was also significantly higher in patients with PCOS than in controls (110+/-8.5 and 77+/-3.7 min respectively, P<0.01). To quantify the orderliness of LH release, we used ApEn. PCOS patients had remarkably increased disorderliness (higher ApEn) of LH release (1.09+/-0.04 vs 0.77+/-0.08 in controls, P = 0.002). Mean serum LH concentration, mass of LH secreted per burst, and LH production rate in PCOS, but not in normal adolescents, correlated positively with androstenedione (P<0.02, 0.02 and 0.05 respectively). The same parameters also correlated positively with 17-OHP (P<0.05, 0.02 and 0.05 respectively). Stepwise regression analysis unmasked a negative influence of BMI in PCOS on both mass of LH secreted per burst (r = -0.77, P<0.005) and LH production rate (r = -0.70, P<+/0.01). We conclude that PCOS adolescents secrete LH molecules with amplified frequency and burst mass and with markedly disrupted orderliness. A rise in basal (non-pulsatile) LH release, more basic LH isoforms, and/or a prolongation or asymmetry of the LH secretory burst could account for the apparently prolonged LH half-life. Determining whether disorderliness of the amplified pituitary LH release process is an intrinsic abnormality in PCOS. or reflects androgen excess, may help to clarify the pathophysiology of this oligo-ovulatory syndrome in young women.

Oral desmopressin treatment of central diabetes insipidus in children.

To assess the efficacy of treatment with oral desmopressin (DDAVP), 20 patients, aged 5-20 y, with central diabetes insipidus were studied during 3 d of hospitalization and for 3 months at the outpatient clinic. At baseline the median rate of diuresis was 12.7 ml kg-1 h-1. Urinary output decreased significantly under treatment with an increase in urinary osmolality, normalization of plasma osmolality and absence of nocturia. Patients were discharged from hospital with a median dose of 500 micrograms d-1 (100-1200 micrograms d-1). An adjustment in dosage was necessary in seven patients during follow-up, resulting in a final dose of 600 micrograms d-1. Body weight and DDAVP doses (r = 0.75, p = 0.001) and body surface and DDAVP doses (r = 0.72, p < 0.001) were significantly correlated. The average dosage was 474 +/- 222 micrograms m-2 d-1 (mean +/- SD). The oral DDAVP treatment remained effective during the 3 months of follow-up. This therapy offers an alternative for the treatment of central diabetes insipidus in children.

Gonadotropin secretion in prepubertal normal and agonadal children evaluated by ultrasensitive time-resolved immunofluorometric assays.

To analyze a possible gonadal effect on the control of gonadotropin secretion during the prepubertal period, we have measured the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) serum concentrations in children with primary gonadal failure (PGF). We measured them using an ultrasensitive immunofluorometric assay (IFMA) in a single daytime serum sample and compared the results with those obtained with a radioimmunoassay (RIA) technique. The patients were 22 children with PGF (13 girls and 9 boys) aged 0.56-15.4 years and 58 normal children (28 girls and 30 boys) aged 0.08-16 years. In the normal group there were significant changes in serum LH and FSH concentrations in relation to sex and pubertal development. These changes were more evident especially in LH concentrations when using IFMA. We observed that during the prepubertal period the normal LH levels (mean +/- SD) were detectable with this method at concentrations well below the limit RIA could detect (girls 0.026 +/- 0.012 IU/l, and boys 0.025 +/- 0.01 IU/l), while at the onset of puberty these LH levels rose significantly in both sexes (girls 1.0 +/- 0.79 IU/l, boys 1.7 +/- 0.7 IU/l; p < 0.01 vs. prepubertal group), reaching similar values to those observed in FSH concentrations (prepubertal girls 1.9 +/- 0.89 IU/l, boys 0.73 +/- 0.41 IU/l; early pubertal girls 3.1 +/- 0.9 IU/l, boys 2.6 +/- 1.3 IU/l). At prepubertal age, most PGF patients showed normal gonadotropin serum levels (particularly LH) when measured by RIA. However, these same samples-when measured by IFMA-showed LH and FSH levels clearly higher than normal in almost all-10 of 12-patients (PGF girls, n = 8, LH 1.1 +/- 1.0 IU/l, FSH 34 +/- 30 IU/l; PGF boys, n = 4, LH 0.13 +/- 0.12 IU/l, FSH 6.5 +/- 5.7 IU/l). We conclude that, during the so-called 'juvenile pause' when the gonadotropin concentrations could be reliably measured, supranormal gonadotropin levels could be observed during a single daytime serum sample in patients with PGF. These findings suggest that during this period of life the gonads contribute to the negative feedback regulation of gonadotropin levels.

Reproducibility and comparison of growth hormone secretion tests.

To assess the degree of reproducibility of spontaneous GH secretion and pharmacological tests we studied 15 prepubertal children with short stature and abnormal growth rate. In all children, spontaneous overnight GH secretion was measured followed by a clonidine test in 8 children and an arginine test in the remaining 7. The same protocol was repeated a week later. Intra-individual variability of GH secretion in both physiological and pharmacological tests was expressed as the coefficient of variation (CV%). No significant difference was found between the first and second value of parameters of spontaneous GH secretion. Maximum spontaneous GH peak (MS) and mean 12-h GH concentration (MGH) correlated significantly (r = 0.78, p < 0.001). Mean CV% of all parameters of repeated GH profiles (around 30%) were lower than those of provocative tests (around 70%) (p < 0.05). No significant difference was found between CV% of clonidine and arginine tests. There was no correlation between MGH or MS and GH response to provocative test in the same child. We found a significant correlation between the log transformed maximum provocative GH response to the arginine test and the length of the time interval (in min) from the end of the last GH peak in the previous profile to the time zero of the provocative test (r = 0.60, p < 0.05). This relationship was not found for the clonidine test. We conclude that spontaneous GH secretion in children with short stature is more reproducible than stimulated GH response with a week's difference. Perhaps the higher variability of provocative GH secretion may be related to the state of the endogenous hypothalamic rhythm of both GHRH and somatostatin release at the time of the test.