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3.
Endocr Relat Cancer ; 26(2): G1-G18, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30400055

RESUMO

The management of cancer patients has changed due to the considerably more frequent use of immune checkpoint inhibitors (ICPIs). However, the use of ICPI has a risk of side effects, particularly endocrine toxicity. Since the indications for ICPI are constantly expanding due to their efficacy, it is important that endocrinologists and oncologists know how to look for this type of toxicity and how to treat it when it arises. In view of this, the French Endocrine Society initiated the formulation of a consensus document on ICPI-related endocrine toxicity. In this paper, we will introduce data on the general pathophysiology of endocrine toxicity, and we will then outline expert opinion focusing primarily on methods for screening, management and monitoring for endocrine side effects in patients treated by ICPI. We will then look in turn at endocrinopathies that are induced by ICPI including dysthyroidism, hypophysitis, primary adrenal insufficiency and fulminant diabetes. In each chapter, expert opinion will be given on the diagnosis, management and monitoring for each complication. These expert opinions will also discuss the methodology for categorizing these side effects in oncology using 'common terminology criteria for adverse events' (CTCAE) and the difficulties in applying this to endocrine side effects in the case of these anti-cancer therapies. This is shown in particular by certain recommendations that are used for other side effects (high-dose corticosteroids, contraindicated in ICPI for example) and that cannot be considered as appropriate in the management of endocrine toxicity, as it usually does not require ICPI withdrawal or high-dose glucocorticoid intake.


Assuntos
Antineoplásicos Imunológicos/efeitos adversos , Doenças do Sistema Endócrino/induzido quimicamente , Imunoterapia/efeitos adversos , França , Humanos , Imunoterapia/métodos
4.
Mol Cell Endocrinol ; 450: 105-112, 2017 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-28461075

RESUMO

Ovarian monitoring requires the determination of serum estradiol and progesterone levels. We investigated whole follicular steroidogenesis under rFSH in medically assisted procreation (MAP: 26 IVF, 24 ICSI) compared to 11 controls (IUI). Estrone, estradiol, Δ4-androstenedione, testosterone, progesterone and 17-hydroxyprogesterone were measured by immunoassay and mass spectrometry except for estrogens. At the start of a spontaneous or induced cycle, steroids levels fluctuated within normal ranges: estradiol (314-585 pmol/L), estrone (165-379 pmol/L) testosterone (1.3-1.6 nmol/L), Δ4-androstenedione (4.5-5.6 nmol/L), 17-hydroxyprogesterone (2.1-2.2 nmol/L) and progesterone (1.8-1.9 nmol/L). 17-hydroxyprogesterone, Δ 4-androstenedione and estradiol predominated. Then estradiol and oestrone levels rise, but less markedly for oestrone in IUI. In MAP, rFSH injections induce a sharp increase in estrogens associated with a rise in 17-hydroxyprogesterone and Δ4-androstenedione levels, disrupting oestrogen/androgen ratios. rFSH stimulation induces an ovarian hyperplasia and Δ4pathway which could become abnormal. Determining 17-hydroxyprogesterone and Δ4-androstenedione levels with LC-MS/MS may therefore be useful in managing recurrent MAP failures.


Assuntos
17-alfa-Hidroxiprogesterona/sangue , Androstenodiona/sangue , Hormônio Foliculoestimulante/farmacologia , Espectrometria de Massas , Folículo Ovariano/patologia , Proteínas Recombinantes/farmacologia , Reprodução/efeitos dos fármacos , Feminino , Humanos , Hiperplasia , Folículo Ovariano/efeitos dos fármacos , Estudos Retrospectivos
5.
Andrology ; 4(6): 1169-1177, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27637014

RESUMO

The most common sex chromosome aneuploidy, Klinefelter syndrome (KS), is associated with primary gonadal failure and increased morbidity and mortality from cardiometabolic disorders in adulthood. Children with KS also have a high prevalence of metabolic syndrome (MetS) features. To assess the relationship of gonadal and cardiometabolic function in children with KS, we evaluated serum hormones [gonadotropins, inhibin B (INHB), anti-mullerian hormone (AMH), total testosterone (TT)], and features of MetS (waist circumference, fasting lipid panel, fasting blood glucose (FBG), and blood pressure) in 93 pre-pubertal boys with KS age 4-12 years (mean 7.7 ± 2.5 years). The cohort was grouped by age and tanner stage, and biomarkers were compared to normal ranges. A total of 80% of this pre-pubertal cohort had ≥1 feature of metabolic syndrome (MetS) and 11% had ≥3 features of MetS. Risk of MetS was independent of age and body mass index. Sertoli cell dysfunction was common with 18% having an INHB below the normal range. A low INHB was associated with higher FBG, triglycerides, LDL, and lower HDL (p < 0.05). An INHB <50 ng/dL yielded a sensitivity of 83% and a specificity of 79% for having ≥3 features of MetS. INHB and AMH positively correlated with each other (p < 0.001), and high AMH was protective of MetS. TT was below the lower limit of normal in 49% of subjects, with mean values significantly lower than expected (3.3 ng/dL vs. 4.9 ng/dL, p < 0.0001), however, no convincing relationship between TT and MetS was seen. In conclusion, gonadal and cardiometabolic dysfunction are prevalent in pre-pubertal boys with KS. Although the relationship of testosterone deficiency and MetS is well-known, this study is the first to report an association between impaired Sertoli cell function and cardiometabolic risk.


Assuntos
Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Hipogonadismo/fisiopatologia , Síndrome de Klinefelter/fisiopatologia , Testosterona/sangue , Circunferência da Cintura/fisiologia , Hormônio Antimülleriano/sangue , Criança , Pré-Escolar , Hormônio Foliculoestimulante/sangue , Humanos , Hipogonadismo/sangue , Inibinas/sangue , Síndrome de Klinefelter/sangue , Hormônio Luteinizante/sangue , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/fisiopatologia , Células de Sertoli/metabolismo , Triglicerídeos/sangue
6.
Eur J Obstet Gynecol Reprod Biol ; 183: 52-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25461353

RESUMO

Transvaginal pelvic ultrasound is the first-line imaging examination for presumed benign ovarian tumors (PBOT) in adult women (Grade A). Ultrasound is sufficient for characterizing a unilocular anechoic cyst smaller than 7cm (Grade A). Magnetic resonance imaging is the recommended second-line investigation for indeterminate masses or masses larger than 7cm (Grade B). Serum CA-125 assay is not recommended for first-line diagnosis in adult women (Grade C). In women with a unilocular anechoic cyst, hormone therapy is ineffective and not recommended (Grade A). Ultrasound-guided aspiration is not recommended (Grade B). Abstention is an option in adult women with a unilocular asymptomatic anechoic cyst smaller than 10cm and no history of cancer (Grade B). If symptoms develop, laparoscopy is the gold standard for surgical treatment of PBOT (Grade A). Conservative surgical treatment (cystectomy) should be preferred to oophorectomy in pre-menopausal women without a previous history of cancer (Grade C). In cases of suspected adnexal torsion, laparoscopic surgical exploration is recommended (Grade B). Conservative treatment or detorsion without oophorectomy is recommended for pre-menopausal women regardless of the estimated torsion duration and macroscopic appearance of the ovary (Grade B). During pregnancy, expectant management is recommended for unilocular asymptomatic anechoic cysts smaller than 6cm (Grade C).


Assuntos
Gerenciamento Clínico , Neoplasias/diagnóstico , Neoplasias/terapia , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/terapia , Anticoncepcionais Orais Hormonais/uso terapêutico , Danazol/uso terapêutico , Quimioterapia Combinada , Feminino , França , Humanos , Laparoscopia , Imageamento por Ressonância Magnética , Ovariectomia , Progestinas/uso terapêutico , Ultrassonografia
7.
J Gynecol Obstet Biol Reprod (Paris) ; 42(8): 752-9, 2013 Dec.
Artigo em Francês | MEDLINE | ID: mdl-24210243

RESUMO

Cancer Antigen 125 (CA125) and Human Epididymis Protein 4 (HE4) are the most studied ovarian tumor markers. Their diagnostic performance for identification of ovarian cancer are superior to CA19-9, CA72-4, and carcinoembryonic antigen, which are no more recommended for the diagnosis of presumed benign ovarian tumor. HE4 (>140 pmol/L) is superior to CA125 (>30 U/mL) in terms of specificity and positive likelihood ratio. CA125 and HE4 can be combined into an algorithm ROMA, or associated to clinical information (composite index), biological data (OVA1) or imaging (Risk for Malignancy Index (RMI), LR2). ROMA algorithm is an exponential equation combining plasmatic concentrations of HE4 and CA125. ROMA is more sensitive and less specific than HE4 in predicting epithelial ovarian cancer. ROMA is more accurate in post-menopausal women. The performance of ROMA is lower than the ultrasound model LR2 in differentiating malignant from benign ovarian tumors, whatever the hormonal status. The composite index combining CA125 with a symptoms index (pain, abdominal distension, bloating, difficulty eating) has a good sensitivity in a screening program, but because of a 12% false positive rate, ultrasound is required before management. The RMI algorithm is based on serum CA125, ultrasound findings (septation, solid zones, metastases, ascite, bilaterality) and menopausal status. RMI is less sensitive, but more specific than ROMA or OVA1 for the classification of ovarian masses. The addition of HE4 to RMI seems to be the most accurate. The subjective evaluation of ovarian cysts by sonography and color Doppler is better than ROMA and RMI algorithms, and not affected by the hormonal status.


Assuntos
Biomarcadores Tumorais/sangue , Cistos Ovarianos/diagnóstico , Neoplasias Ovarianas/diagnóstico , Antígenos de Neoplasias/sangue , Antígeno Ca-125/sangue , Antígeno CA-19-9/sangue , Feminino , Glicoproteínas/sangue , Humanos , Cistos Ovarianos/sangue , Neoplasias Ovarianas/sangue , Proteínas/análise , Fatores de Risco , Proteína 2 do Domínio Central WAP de Quatro Dissulfetos
8.
Int J Androl ; 34(6 Pt 2): e518-25, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21535007

RESUMO

Micropenis is defined as a stretched penile length of less than 2-2.5SD for age. Aetiologies include hypogonadotropic hypogonadism, testicular dysgenesis, defects in testosterone synthesis, androgen resistance [5α-reductase (5αR) deficiency or partial androgen insensitivity] and other rare causes like growth hormone GH deficiency. Often, the cause remains unknown. The aim of this study was to determine whether isolated micropenis with normal plasma testosterone could hide a molecular defect in the androgen pathway. Twenty-six boys with isolated micropenis were included in this study. All of them had 46,XY karyotype, normal luteinizing hormone and follicle-stimulating hormone and a normal plasma testosterone response to human chorionic gonadotropin testing. Androgen receptor (AR), 5αR and steroidogenic factor 1 (SF1) genes were sequenced. A mutation in the AR gene was found in two patients, and a new mutation in the SF1 gene was found in one patient who was the only one to have a low level of inhibin B (InhB). This is the first report of isolated micropenis as a revealing symptom of AR and SF1 mutations. Anti-Mullerian hormone and InhB should thus be evaluated in patients with isolated micropenis, even when plasma testosterone is in the normal range. Detection of gene mutations is helpful for diagnosis, treatment and genetic counselling for probands.


Assuntos
Doenças dos Genitais Masculinos/genética , Sequência de Aminoácidos , Criança , Pré-Escolar , Hormônio Foliculoestimulante/sangue , Humanos , Cariotipagem , Hormônio Luteinizante/sangue , Masculino , Dados de Sequência Molecular , Mutação , Pênis/anormalidades , Homologia de Sequência de Aminoácidos , Fator Esteroidogênico 1/química , Fator Esteroidogênico 1/genética , Testosterona/sangue
10.
Ann Biol Clin (Paris) ; 67(3): 283-92, 2009.
Artigo em Francês | MEDLINE | ID: mdl-19411230

RESUMO

Inhibins, activins, and anti-Mullerian hormone (AMH) are gonadal dimeric peptides produced in ovaries and testes by homologous cells, granulosa cells and Sertoli cells, respectively. The production of inhibins is driven by FSH, that of AMH may indirectly depends on FSH, while it is down regulated, at least in the male, by testosterone. In the past decade, measurements of serum inhibin and AMH have provided useful tools for clinical investigation in gonadal disorders: pseudohermaphroditism, androgen insensitivity, anorchidism, gonadal dysgenesis, disorders of pubertal developpement. Inhibins, activins, and AMH are also reliable markers of gonadal tumors. They are extensively used as indexes of fertility: in the male the production of inhibin B reflects the spermatogenetic activity, in women both inhibin B and AMH levels are correlated with the number of preantral and early antral follicles and reflect the ovarian reserve of follicles available for recruitment.


Assuntos
Ativinas/fisiologia , Hormônio Antimülleriano/fisiologia , Inibinas/fisiologia , Adolescente , Envelhecimento/fisiologia , Criança , Pré-Escolar , Feminino , Hormônio Foliculoestimulante/antagonistas & inibidores , Hormônio Foliculoestimulante/fisiologia , Humanos , Lactente , Inibinas/sangue , Masculino , Ovário/fisiologia , Testículo/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Adulto Jovem
11.
J Clin Endocrinol Metab ; 93(6): 2202-5, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18381569

RESUMO

BACKGROUND: The neonatal-midinfancy surge in pulsatile gonadotropin secretion is attributable to an increase in GnRH pulse amplitude and is associated with a rapid expansion of Leydig and Sertoli cell populations with concomitant surges in testosterone, inhibin, and anti-Mullerian hormone production as well as an increase in testicular volume. Boys with congenital hypogonadotropic hypogonadism (HH) do not activate these processes. A potential cause for azoospermia and infertility in adult life is deficient proliferation of immature Sertoli cells before and during puberty due to the absence of FSH. OBJECTIVE: The objective of the study was to investigate whether early postnatal continuous sc infusion of gonadotropins could mimic the physiological growth of testes and to evaluate responses of the Leydig and Sertoli cells to early gonadotropin replacement. DESIGN AND METHODS: Two neonates (P1 with hypotuitarism and P2 with HH) with micropenis and microorchidism were treated for 6 months with high doses of recombinant LH and FSH (a gift of Luveris and Gonal-F from Serono, Lyon, France) delivered sc with an insulin pump. RESULTS: Gonadotropin continuous sc infusion increased mean serum LH and FSH to normal or supranormal levels. Mean testosterone increased from undetectable levels to 7.6 and 5.2 nmol/liter, respectively, in P1 and P2. Inhibin B and anti-Müllerian hormone increased to normal levels. Mean testicular volume increased from 0.45 to 0.57 ml at birth to 2.10 ml at 7 months. Stretched penile length increased from 8 to 30 mm (P1) and 12 to 48 mm (P2). CONCLUSIONS: The present regimen induced physiological postnatal testes growth and high-normal activation of Leydig and Sertoli cells.


Assuntos
Hormônio Foliculoestimulante/administração & dosagem , Hipogonadismo/tratamento farmacológico , Hormônio Luteinizante/administração & dosagem , Hormônio Antimülleriano/sangue , Gonadotropinas/sangue , Terapia de Reposição Hormonal , Humanos , Hipogonadismo/patologia , Lactente , Recém-Nascido , Bombas de Infusão , Inibinas/sangue , Injeções Subcutâneas , Masculino , Tamanho do Órgão/efeitos dos fármacos , Proteínas Recombinantes/administração & dosagem , Testículo/efeitos dos fármacos , Testículo/patologia , Testosterona/sangue , Fatores de Tempo
12.
Hum Reprod ; 21(11): 2941-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16877377

RESUMO

BACKGROUND: In normo-ovulatory infertile women undergoing mild ovarian stimulation out of IVF, FSH stimulation regimen must be carefully adjusted to control the number of recruited follicles and to prevent multiple pregnancies. The aim of this prospective study was to assess the effect of the timing of FSH administration (fixed dose and duration) on the number of large follicles. METHODS: Women were prospectively randomized by means of sealed envelopes to receive daily 112.5 IU recombinant FSH (rFSH), either from cycle day (CD) 2-6 (Group A) or from CD 7-11 (Group B). Hormonal measurements and follicular ultrasound assessments were performed on CD 2, 7 and 12. RESULTS: On CD 12, the development rate of exactly two follicles >or=14 mm in diameter was significantly lower in Group A than in Group B (4% of women versus 42%, P = 0.002). Although the pattern of serum estradiol (E(2)) concentrations in Group A displayed a plateau from CD 7, the cancellation rate for overstimulation (more than three follicles >or=14 mm in diameter) was significantly increased (P = 0.009). CONCLUSIONS: Preventing the closure of the FSH window by mid to late follicular phase FSH administration better fulfils the objective of obtaining a limited number of large follicles than surpassing the FSH threshold by an early administration.


Assuntos
Hormônio Foliculoestimulante/farmacologia , Fase Folicular/fisiologia , Indução da Ovulação/métodos , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Fase Folicular/efeitos dos fármacos , Humanos , Hormônio Luteinizante/sangue , Ciclo Menstrual/efeitos dos fármacos , Ciclo Menstrual/fisiologia , Folículo Ovariano/diagnóstico por imagem , Folículo Ovariano/fisiologia , Ovulação/efeitos dos fármacos , Ovulação/fisiologia , Proteínas Recombinantes/farmacologia , Valores de Referência , Ultrassonografia
13.
Ann Biol Clin (Paris) ; 62(2): 155-63, 2004.
Artigo em Francês | MEDLINE | ID: mdl-15047467

RESUMO

The diagnosis of growth hormone (GH) deficiency is based on the GH biological response to pharmacological stimulation tests. The cut-off value defining normality is the same whatever the GH assay used. In a group of the French Society for Clinical Biology (SFBC), we have evaluated whether differences between the GH concentrations obtained with the 9 commercial GH assays available in France exist or not. The study samples consisted of 72 serum pools and serial dilutions of the recombinant GH 22 kDa international standard, IS 98/574. These dilutions were performed by using 3 different diluents: the specific diluent provided by the manufacturers and thus different from one assay to another, serum without GH and heparin plasma without GH. Despite being calibrated against the same international standard, the different assays proposed variable conversion factors between microg and mIU, and we decided to express the results in mIU. The GH concentrations obtained for the 72 serum pools with the 9 assays were highly correlated, but absolute concentrations were significantly different from one assay to another. In particular, the ratio between the concentrations measured with both assays giving the lowest and highest concentration in the same sample respectively was about 50%. In the recovery test executed by adding the international standard, the slope of the regression curve describing the relationship between expected and measured concentrations was different of 1 in all but one assay. Furthermore, for a given assay and a given expected concentration, the measured values were sometimes different by up to 30% depending on the diluent used. These results led us to advise the manufacturers to calibrate their assays against the recombinant GH international standard, IS 98/574, to take into account the matrix effect detected in our study and to use the official conversion factor of 3 mIU/microg. Waiting for this new calibration, it is recommended that the results should be expressed in mIU/L and that serum samples should be used for the measurement of GH instead of plasma samples.


Assuntos
Hormônio do Crescimento/sangue , Análise Química do Sangue/métodos , Análise Química do Sangue/normas , Humanos , Reprodutibilidade dos Testes
15.
Diabetes Metab ; 27(3): 339-44, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11431599

RESUMO

OBJECTIVE: To investigate the frequency of macrosomia in an homogeneous cohort of type 1 diabetic mothers and to analyze the influence of maternal factors and glycemic control on the incidence of fetal macrosomia. MATERIAL AND METHODS: Fifty-five consecutive type 1 diabetic first-pregnancies were prospectively studied. Macrosomia was defined by a ponderal index above the 90(th) percentile. Venous cord blood levels of insulin, C peptide and leptin were measured at delivery. The influence of HbA1c levels and other maternal variables on the occurrence of macrosomia and on the ponderal index was assessed using a stepwise regression logistic model. RESULTS: The mean (+/- SD) birth weight was 3482 (+/- 497) g at 37.4 +/- 1.0 weeks gestation. Macrosomia occurred in 29 cases (53.7%). Fetal insulin, C peptide and leptin levels were significantly higher in macrosomic than in non macrosomic infants. Maternal age, duration of diabetes, pregravid body mass index, parity, weight gain during pregnancy, presence of a microangiopathy, nephropathy, smoking habits, gestational hypertension or preeclampsia, and HbA1c levels throughout pregnancy did not differed between mothers of macrosomic and non macrosomic infants. In the stepwise analysis none of these covariates was explanatory of the ponderal index. CONCLUSIONS: The frequency of macrosomia remains very high in infants of type 1 diabetic mothers despite a reasonable degree of glycemic control. The variability of the fetal growth response to mild hyperglycemia prompts for the identification of other factors involved in the modulation of fetal growth.


Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Desenvolvimento Embrionário e Fetal , Macrossomia Fetal/epidemiologia , Gravidez em Diabéticas/fisiopatologia , Adulto , Peso ao Nascer , Glicemia/análise , Peptídeo C/sangue , Feminino , Macrossomia Fetal/sangue , Idade Gestacional , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemia/epidemiologia , Recém-Nascido , Insulina/sangue , Leptina/sangue , Idade Materna , Placenta/anatomia & histologia , Gravidez , Estudos Prospectivos , Valores de Referência
16.
J Clin Endocrinol Metab ; 86(4): 1778-81, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11297617

RESUMO

We report an unusual observation of a 3.8-yr-old boy with McCune-Albright syndrome (MAS) associated with abnormal prepubertal testis enlargement and no sexual precocity. Physical examination showed café-au-lait skin lesions, enlarged testes, prepubertal sized penis, and no pubic or axillary hair. Skeletal radiography disclosed fibrous dysplasia. The serum testosterone level was 0.58 nmol/L and remained below 1.4 nmol/L during the 4-yr follow-up. By contrast, serum inhibin B and anti-Mullerian hormone concentrations were abnormally increased up to 255 pg/mL (childhood range, 35--180) and 792 pmol/L (childhood range, 309--566), respectively. The LH response to a GnRH test was in the prepubertal range, whereas the FSH response was blunted. This abnormal hormone concentration profile indicates autonomous hyperfunction of Sertoli cells, with no evidence of Leydig cell activation. Testicular histology showed tubules with marked Sertoli cell hyperplasia and very rare germinal cells, and interstitial tissue containing mesenchymal cells but no mature Leydig cells. DNA sequence analysis from bone and testis tissues detected the known activating mutation in MAS that results in replacement of Arg by His at codon 201 of the G(s)alpha protein. Other endocrine tests showed excessive GH secretion and moderate adrenal androgen hypersecretion. These findings are consistent with the occurrence of an activating mutation of the G(s)alpha gene mainly expressed in Sertoli cells and weakly expressed or absent in Leydig cells. Abnormal prepubertal testicular enlargement extends the clinical spectrum of MAS, suggesting that determination of serum inhibin B and anti-Mullerian hormone should be considered in boys with this syndrome. This observation demonstrates the usefulness of detailed molecular and biological investigations in atypical cases of MAS.


Assuntos
Displasia Fibrosa Poliostótica/complicações , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Mutação/fisiologia , Células de Sertoli/fisiologia , Testículo/anormalidades , Sequência de Bases/genética , Pré-Escolar , Anormalidades Congênitas/etiologia , Anormalidades Congênitas/patologia , Humanos , Masculino , Mutação/genética , Isoformas de Proteínas/genética , Puberdade , Testículo/patologia
17.
Metabolism ; 49(10): 1243-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11079810

RESUMO

Treatment with small doses of subcutaneous insulin is being investigated as a possible approach to prevent type 1 diabetes in humans. The mechanism of prophylactic insulin therapy could involve the inhibition of beta-cell secretory activity and/or the initiation of an active immunoregulatory process. To evaluate the pure metabolic effect of exogenous insulin, the present study assessed whether daily subcutaneous administration of ultralente insulin alters beta-cell function in normal adults. Fourteen healthy adults were randomized to receive 0.2 U/kg x d ultralente insulin (Ultratard; Novo Nordisk, Bagsvaerd, Denmark) or placebo subcutaneously once daily for 30 days. Plasma glucose, C-peptide, and insulin concentrations were measured in the fasting state and 1 hour after a standardized breakfast, during treatment and during a recovery period of 10 days. Insulin administration induced a 15% to 40% decrease of fasting plasma C-peptide. In contrast, postbreakfast plasma C-peptide increased by 40% to 90% in subjects receiving insulin. Fasting and postbreakfast C-peptide concentrations were significantly different between groups during the injection period after adjustment for baseline concentrations (P < .05, ANOVA with repeated measures). These alterations disappeared 3 days after cessation of insulin treatment. The present regimen of exogenous insulin alters endogenous insulin secretion in normal subjects. Instead of the expected beta-cell rest, the effect appeared to be dual, with insulin secretion decreasing in the basal state and increasing after meals.


Assuntos
Insulina de Ação Prolongada/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Período Pós-Prandial/fisiologia , Adulto , Peptídeo C/análise , Jejum , Feminino , Humanos , Ilhotas Pancreáticas/fisiologia , Masculino , Aumento de Peso
18.
J Pediatr Endocrinol Metab ; 13 Suppl 1: 723-37, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10969915

RESUMO

Since 1981, GnRH agonist administration has been the treatment of choice for central precocious puberty. Continuous administration of the agonist, instead of permanently stimulating gonadotropin secretion, deeply suppresses LH and FSH levels and induces a marked inhibition of gonadal activity and regression of clinical symptoms. This inhibitory effect is due both to specific kinetic parameters relative to natural GnRH, and to marked alterations of the biosynthetic pathways of gonadotropin subunits. The half disappearance time of infused agonists is 3-10 fold that of natural GnRH. This means that the residence time of GnRH agonists is significantly longer than that of GnRH. The resistance of agonist to enzymatic degradation, mainly due to the substitution of a hydrophobic D-amino acid for glycine 6, is one of the factors involved in the increased availability of GnRH superagonists. The paradoxical effects of GnRH superagonists are still incompletely understood. In children long-term treated with depot formulations of triptorelin or leuprorelin, alpha-subunit secretion is markedly increased, and remains sensitive to exogenous GnRH, which demonstrates that the gonadotrophs are not totally desensitized. Despite the sustained stimulation of a-subunit secretion, no deleterious side effects, either during therapy or during post-therapy follow-up, have been reported in children treated with GnRH agonists. It should be noted that alpha-subunit responsiveness to exogenous GnRH decreases progressively after several years of treatment, although it is never completely abolished. On the other hand, LH beta-subunit secretion is suppressed as evidenced by radioimmunoassay of LH beta-subunit in serum chromatographic fractions from children treated with triptorelin. This differential pattern of secretion parallels that of mRNA levels in rat pituitary after in vivo exposure to triptorelin. Both pharmacodynamic and pharmacokinetic data can help diagnose the situations of resistance or escape. The lack of clinical effect of GnRH in the treatment of precocious puberty can be due to true resistance, or to an inappropriate injection schedule, or to abnormal metabolism. Measurement of serum alpha-subunit level, and, if needed, of serum agonist level, generally provides the answer.


Assuntos
Hormônio Liberador de Gonadotropina/agonistas , Preparações de Ação Retardada , Humanos , Cinética , Hormônio Luteinizante/sangue , Pediatria/métodos , Isoformas de Proteínas/sangue , Puberdade Precoce/tratamento farmacológico
19.
J Clin Endocrinol Metab ; 85(9): 3002-8, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10999776

RESUMO

We describe a woman with complete hypogonadotropic hypogonadism and a new compound heterozygous mutation of the GnRH receptor (GnRHR) gene. A null mutation L314X leading to a partial deletion of the seventh transmembrane domain of the GnRHR is associated with a Q106R mutation previously described. L314X mutant receptor shows neither measurable binding nor inositol phosphate production when transfected in CHO-K1 cells compared to the wild-type receptor. The disease is transmitted as an autosomal recessive trait, as shown by pedigree analysis. Heterozygous patients with GnRHR mutations had normal pubertal development and fertility. The present study shows an absence of LH and FSH response to pulsatile GnRH administration (20 microg/pulse, sc, every 90 min). However, GnRH triggered free alpha-subunit (FAS) pulses of small amplitude, demonstrating partial resistance to pharmacological doses of GnRH. FSH, LH, and FAS concentrations were evaluated under chronic estrogen treatment and repeat administration of GnRH. Not only were plasma FSH, LH, and FAS concentrations decreased, but FAS responsiveness was reduced. This new case emphasizes the implication of the GnRH receptor mutations in the etiology of idiopathic hypogonadotropic hypogonadism. We also have evidence for a direct negative estrogen effect on gonadotropin secretion at the pituitary level, dependent on the GnRHR signaling pathway.


Assuntos
Estrogênios/efeitos adversos , Gonadotropinas/deficiência , Hipogonadismo/genética , Mutação/genética , Receptores LHRH/genética , Sequência de Aminoácidos , Animais , Células CHO , Criança , Cricetinae , Feminino , Hormônio Foliculoestimulante/sangue , Subunidade alfa de Hormônios Glicoproteicos/sangue , Gonadotropinas/farmacologia , Haplótipos , Humanos , Hormônio Luteinizante/sangue , Dados de Sequência Molecular , Fenótipo , Conformação Proteica , RNA Mensageiro/biossíntese , RNA Mensageiro/genética
20.
J Clin Endocrinol Metab ; 85(9): 3208-17, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10999810

RESUMO

Dehydroepiandrosterone (DHEA; 50 and 25 mg) and placebo tablets were orally administered daily to 24 healthy aging men and women (67.8 +/- 4.3 yr) for 8 days according to a balanced incomplete block design. Nine blood tests on both the first and eighth days allowed the measurement of DHEA, its sulfate DHEAS, and metabolites: testosterone, 5alpha-androstan-3alpha,17beta-diol glucuronide, estradiol, and estrone. Relatively low background levels of DHEA(S) were observed, and with the reestablishment of "young" levels, four important results were obtained. 1) Blood DHEA had an apparent terminal half-life of more than 20 h, the same order of magnitude as that of blood DHEAS, a result explainable by back-hydrolysis of the large amount of DHEAS formed after oral administration of DHEA, a mechanism providing long-lived unconjugated DHEA and metabolites. 2) The metabolic conversion of DHEAS to DHEA was significantly greater in women than in men. 3) No accumulation of steroids was observed. 4) No worrying transformation to androgen and estrogen was recorded; indeed, the limited increased estradiol in aged women could be predicted to be beneficial. These results suggested that daily oral administration of DHEA (25/50 mg) is safe in elderly subjects. The 50-mg dose was chosen for a 1 yr, double blind, placebo-controlled trial of daily oral administration of DHEA in 60- to 80-yr-old individuals (DHEAge).


Assuntos
Desidroepiandrosterona/farmacocinética , Idoso , Androstano-3,17-diol/sangue , Área Sob a Curva , Estudos Cross-Over , Desidroepiandrosterona/administração & dosagem , Desidroepiandrosterona/sangue , Sulfato de Desidroepiandrosterona/sangue , Método Duplo-Cego , Estradiol/sangue , Estrona/sangue , Feminino , Meia-Vida , Humanos , Masculino , Pessoa de Meia-Idade , Testosterona/sangue
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