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Terasawa E. The mechanism underlying the pubertal increase in pulsatile GnRH release in primates. J Neuroendocrinol 2022; 34:e13119. [PMID: 35491543 PMCID: PMC9232993 DOI: 10.1111/jne.13119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 02/17/2022] [Accepted: 03/01/2022] [Indexed: 11/29/2022]
Abstract
In primates, the gonatotropin-releasing hormone (GnRH) neurosecretory system, consisting of GnRH, kisspeptin, and neurokinin B neurons, is active during the neonatal/early infantile period. During the late infantile period, however, activity of the GnRH neurosecretory system becomes minimal as a result of gonadal steroid independent central inhibition, and this suppressed GnRH neurosecretory state continues throughout the prepubertal period. At the initiation of puberty, the GnRH neurosecretory system becomes active again because of the decrease in central inhibition. During the progress of puberty, kisspeptin and neurokinin B signaling to GnRH neurons further increases, resulting in the release of gonadotropins and subsequent gonadal maturation, and hence puberty. This review further discusses potential substrates of central inhibition and subsequent pubertal modification of the GnRH neurosecretory system by the pubertal increase in steroid hormones, which ensures the regulation of adult reproductive function.
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Affiliation(s)
- Ei Terasawa
- Department of Pediatrics and Wisconsin National Primate Research CenterUniversity of Wisconsin‐MadisonMadisonWIUSA
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2
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Abstract
An increase in pulsatile release of gonadotropin releasing hormone (GnRH) initiates puberty in mammalian species. While mutations in KISS1 and TAC3 and their receptors, KISS1R and NK3R, respectively, result in the absence or abnormal timing of puberty, the neurocircuitry and precise role of kisspeptin and neurokinin B (NKB) in regulation of the GnRH neurosecretory system in primate puberty remain elusive. This review discusses how kisspeptin and NKB signaling contributes to the pubertal increase in GnRH release in non-human primates and how remodeling of the NKB and kisspeptin signaling circuitry controlling GnRH neurons takes place during the progress of puberty. Importantly, the pubertal remodeling of kisspeptin and NKB signaling ensures efficient functions of the GnRH neurosecretory system that regulates sex-specific reproduction in primates.
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Affiliation(s)
- Ei Terasawa
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA.,Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715, USA
| | - James P Garcia
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715, USA
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Terasawa E, Garcia JP, Seminara SB, Keen KL. Role of Kisspeptin and Neurokinin B in Puberty in Female Non-Human Primates. Front Endocrinol (Lausanne) 2018; 9:148. [PMID: 29681889 PMCID: PMC5897421 DOI: 10.3389/fendo.2018.00148] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/20/2018] [Indexed: 11/25/2022] Open
Abstract
In human patients, loss-of-function mutations in the genes encoding kisspeptin (KISS1) and neurokinin B (NKB) and their receptors (KISS1R and NK3R, respectively) result in an abnormal timing of puberty or the absence of puberty. To understand the neuroendocrine mechanism of puberty, we investigated the contribution of kisspeptin and NKB signaling to the pubertal increase in GnRH release using rhesus monkeys as a model. Direct measurements of GnRH and kisspeptin in the median eminence of the hypothalamus with infusion of agonists and antagonists for kisspeptin and NKB reveal that kisspeptin and NKB signaling stimulate GnRH release independently or collaboratively by forming kisspeptin and NKB neuronal networks depending on the developmental age. For example, while in prepubertal females, kisspeptin and NKB signaling independently stimulate GnRH release, in pubertal females, the formation of a collaborative kisspeptin and NKB network further accelerates the pubertal increase in GnRH release. It is speculated that the collaborative mechanism between kisspeptin and NKB signaling to GnRH neurons is necessary for the complex reproductive function in females.
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Affiliation(s)
- Ei Terasawa
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI, United States
- Department of Pediatrics, University of Wisconsin, Madison, WI, United States
- *Correspondence: Ei Terasawa,
| | - James P. Garcia
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI, United States
| | - Stephanie B. Seminara
- Reproductive Endocrine Unit and the Harvard Reproductive Sciences Center, Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Kim L. Keen
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI, United States
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An isodicentric X chromosome with gonadal dysgenesis in a lady without prominent somatic features of Turner's syndrome. A case report. J Formos Med Assoc 2015; 114:77-80. [PMID: 25618587 DOI: 10.1016/j.jfma.2011.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 04/09/2011] [Accepted: 05/09/2011] [Indexed: 11/22/2022] Open
Abstract
Isodicentric X chromosomes in general have phenotypes characteristic of the resultant X deletions. Gonadotropin levels in Turner's syndrome (TS) girls are high, but have a normal biphasic pattern. Here, we report a 21-year-old lady with primary amenorrhea. Clinical examination revealed a short neck but no other typical stigmata of Turner's syndrome. The levels of gonadotropin were not raised to post-menopausal levels. A chromosome study showed a 45,X/46,X,idic(X)(q22) karyotype. She was diagnosed as having Turner's syndrome.
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Wolfe A, Divall S, Wu S. The regulation of reproductive neuroendocrine function by insulin and insulin-like growth factor-1 (IGF-1). Front Neuroendocrinol 2014; 35:558-72. [PMID: 24929098 PMCID: PMC4175134 DOI: 10.1016/j.yfrne.2014.05.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/01/2014] [Accepted: 05/27/2014] [Indexed: 12/27/2022]
Abstract
The mammalian reproductive hormone axis regulates gonadal steroid hormone levels and gonadal function essential for reproduction. The neuroendocrine control of the axis integrates signals from a wide array of inputs. The regulatory pathways important for mediating these inputs have been the subject of numerous studies. One class of proteins that have been shown to mediate metabolic and growth signals to the CNS includes Insulin and IGF-1. These proteins are structurally related and can exert endocrine and growth factor like action via related receptor tyrosine kinases. The role that insulin and IGF-1 play in controlling the hypothalamus and pituitary and their role in regulating puberty and nutritional control of reproduction has been studied extensively. This review summarizes the in vitro and in vivo models that have been used to study these neuroendocrine structures and the influence of these growth factors on neuroendocrine control of reproduction.
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Affiliation(s)
- Andrew Wolfe
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States.
| | - Sara Divall
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States
| | - Sheng Wu
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States
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McCann-Crosby B, Mansouri R, Dietrich JE, McCullough LB, Sutton VR, Austin EG, Schlomer B, Roth DR, Karaviti L, Gunn S, Hicks MJ, Macias CG. State of the art review in gonadal dysgenesis: challenges in diagnosis and management. INTERNATIONAL JOURNAL OF PEDIATRIC ENDOCRINOLOGY 2014; 2014:4. [PMID: 24731683 PMCID: PMC3995514 DOI: 10.1186/1687-9856-2014-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/14/2014] [Indexed: 11/25/2022]
Abstract
Gonadal dysgenesis, a condition in which gonadal development is interrupted leading to gonadal dysfunction, is a unique subset of disorders of sexual development (DSD) that encompasses a wide spectrum of phenotypes ranging from normally virilized males to slightly undervirilized males, ambiguous phenotype, and normal phenotypic females. It presents specific challenges in diagnostic work-up and management. In XY gonadal dysgenesis, the presence of a Y chromosome or Y-chromosome material renders the patient at increased risk for developing gonadal malignancy. No universally accepted guidelines exist for identifying the risk of developing a malignancy or for determining either the timing or necessity of performing a gonadectomy in patients with XY gonadal dysgenesis. Our goal was to evaluate the literature and develop evidence-based medicine guidelines with respect to the diagnostic work-up and management of patients with XY gonadal dysgenesis. We reviewed the published literature and used the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) system when appropriate to grade the evidence and to provide recommendations for the diagnostic work-up, malignancy risk stratification, timing or necessity of gonadectomy, role of gonadal biopsy, and ethical considerations for performing a gonadectomy. Individualized health care is needed for patients with XY gonadal dysgenesis, and the decisions regarding gonadectomy should be tailored to each patient based on the underlying diagnosis and risk of malignancy. Our recommendations, based on the evidence available, add an important component to the diagnostic and management armament of physicians who treat patients with these conditions.
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Affiliation(s)
- Bonnie McCann-Crosby
- Division of Pediatric Endocrinology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Roshanak Mansouri
- Division of Pediatric and Adolescent Gynecology, Department of Obstetrics and Gynecology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Jennifer E Dietrich
- Division of Pediatric and Adolescent Gynecology, Department of Obstetrics and Gynecology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Laurence B McCullough
- Center for Medical Ethics and Health Policy, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Elise G Austin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Bruce Schlomer
- Division of Pediatric Urology, Department of Surgery, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - David R Roth
- Division of Pediatric Urology, Department of Surgery, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lefkothea Karaviti
- Division of Pediatric Endocrinology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Sheila Gunn
- Division of Pediatric Endocrinology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - M John Hicks
- Department of Pathology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Charles G Macias
- Evidence-Based Outcomes Center, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
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Terasawa E, Guerriero KA, Plant TM. Kisspeptin and puberty in mammals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 784:253-73. [PMID: 23550010 DOI: 10.1007/978-1-4614-6199-9_12] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Since the discovery of the G-protein coupled receptor 54 (kisspeptin receptor) and its ligand, kisspeptin, our understanding of the neurobiological mechanisms that govern the pituitary-gonadal axis has evolved dramatically. In this chapter, we have reviewed progress regarding the relationship between kisspeptin and puberty, and have proposed a novel hypothesis for the role of kisspeptin signaling in the onset of this crucial developmental event. According to this hypothesis, although kisspeptin neurons in the arcuate nucleus (ARC) are critical for puberty, this is simply because these cells are an integral component of the hypothalamic GnRH pulse generating mechanism that drives intermittent release of the decapeptide, as an increase in GnRH is obligatory for the onset of puberty. In our model, ARC kisspeptin neurons play no "regulatory" role in controlling the timing of puberty. Rather, as a component of the neural network responsible for GnRH pulse generation, they subserve upstream regulatory mechanisms that are responsible for the timing of puberty.
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Affiliation(s)
- Ei Terasawa
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715-1299, USA.
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Abstract
Puberty is the developmental process that culminates in reproductive capability and is the result of a complex series of molecular and physiological events. The release of gonadotropin-releasing hormone from specialized neurons of the hypothalamus begins the hormonal cascade that causes gonadal activation and the physical changes of puberty. Several factors have been proposed to influence the activation of the hypothalamus to trigger puberty, but the involved pathways have not been fully elucidated. The recent observations that the age of pubertal onset may be lowering in American girls calls attention to the lack of knowledge of modulating factors that affect the pubertal process. Genes necessary for puberty have been found by studying persons who do not achieve puberty; such studies have provided insights into the pathways necessary for pubertal development. A multidisciplinary focus is required to elucidate the complex mechanisms involved in the initiation and progression of puberty.
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Affiliation(s)
- Sara A DiVall
- Division of Endocrinology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
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9
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Van Vliet G. Hormonal changes during development in Turner's syndrome. ACTA PAEDIATRICA SCANDINAVICA. SUPPLEMENT 2008; 343:31-7. [PMID: 3057806 DOI: 10.1111/j.1651-2227.1988.tb10797.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The hormonal changes observed during infancy, childhood and adolescence in patients with Turner's syndrome are reviewed, with particular emphasis on gonadotrophins and GH. The relative roles of gonadal insufficiency, maturation of the CNS and disturbed body composition (i.e. obesity) are discussed with respect to the endocrine findings.
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Affiliation(s)
- G Van Vliet
- Department of Paediatrics, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Belgium
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10
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Affiliation(s)
- Stephanie B Seminara
- Massachusetts General Hospital, Reproductive Endocrinology Unit, Boston, MA 02114, USA.
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Chrysis D, Spiliotis BE, Stene M, Cacciari E, Davenport ML. Gonadotropin secretion in girls with turner syndrome measured by an ultrasensitive immunochemiluminometric assay. HORMONE RESEARCH 2006; 65:261-6. [PMID: 16582569 DOI: 10.1159/000092516] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 02/20/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIM Gonadotropin levels measured by radioimmunoassays are high in girls with Turner syndrome (TS), but overlap significantly with those of normal girls. We hypothesized that gonadotropin levels would be above the normal range in TS when measured by ultrasensitive assays. METHODS Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured in 68 TS, and 133 control girls using ultrasensitive immunochemiluminometric assays (ICMA). RESULTS FSH levels in TS and normal girls were highest in early childhood (56.0 +/- 39.7 and 2.3 +/- 1.8 IU/l, respectively), declined at 6-10 years of age (11.3 +/- 13.1 and 1.8 +/- 0.9 IU/l, respectively), and then increased again (104.4 +/- 68.9 and 4.9 +/- 2.4 IU/l, respectively). FSH was in the normal range on 11 of 27 occasions in TS girls with ages 5-10 years, and on 3 of 44 occasions in >10 years. Although average LH values were higher than those of controls, they often overlapped the normal range. CONCLUSION A significant number of TS girls have normal gonadotropins by ICMA. Spontaneous gonadotropin levels are not an adequate screening test for the diagnosis of TS but may prove useful for predicting the gonadal function and determining the appropriate timing of estrogen replacement therapy.
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Affiliation(s)
- Dionisios Chrysis
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7039, USA
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12
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Nogueira GP. Follicle profile and plasma gonadotropin concentration in pubertal female ponies. Braz J Med Biol Res 2004; 37:913-22. [PMID: 15264036 DOI: 10.1590/s0100-879x2004000600018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Twelve female ponies were examined daily for 30 days and classified as ovulating (OV; N = 6; 197 +/- 6 kg) or prepubertal (PP; N = 6; 196 +/- 9 kg). Follicles were detected by ultrasound and gonadotropins quantified by radioimmunoassay. The mean diameter of the largest follicles was significantly larger in OV (38 +/- 1 mm) than in PP (26 +/- 2 mm) but there was no difference between groups in the size of the second largest follicle. There were more small follicles (<24 mm) in the PP than in the OV group, but PP fillies had a smaller number of follicles >29 mm than the OV fillies. Follicle-stimulating hormone (FSH) levels did not differ between groups but PP fillies had lower luteinizing hormone (LH) peak (8 +/- 1 ng/ml) and basal (4 +/- 0.5 ng/ml) levels, lower peak magnitude (2 +/- 0.2 ng/ml) and period average (5 +/- 0.6 ng/ml) than OV fillies (32 +/- 4.5, 8 +/- 1.2, 17.1 +/- 6, and 15 +/- 2.3 ng/ml, respectively). The PP group, in contrast to the OV group, showed no relationship between FSH surge and follicle wave emergence. We conclude that an LH concentration higher than 8 ng/ml is needed for follicle growth to a preovulatory size. Wave emergence and FSH secretion seem to be independent events, probably due to an inhibitory neural system in these PP animals. PP fillies may provide a physiological model for the study of follicle wave emergence which apparently does not depend on gonadotropin levels.
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Affiliation(s)
- G P Nogueira
- Departamento de Apoio, Produção e Saúde Animal, Faculdade de Medicina Veterinária, Universidade Estadual Paulista, Araçatuba, SP, Brasil.
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Fujimoto Y, Okuyama T, Iijima M, Tanaka T, Horikawa R, Yamada K, Ogata T. Genitourinary phenotype in XX patients with distal 9p monosomy. Mol Genet Metab 2004; 82:173-9. [PMID: 15172006 DOI: 10.1016/j.ymgme.2004.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 04/05/2004] [Accepted: 04/05/2004] [Indexed: 11/17/2022]
Abstract
Although testicular development has been shown to be variably impaired in XY patients with distal 9p monosomy, ovarian and other genitourinary phenotype has poorly been studied in XX patients monosomic for the distal 9p region. Thus, we studied a 13-month-old infant with 46,XX,der(9)t(9;10)(p23;p13) (case 1) and an 11-year-old girl with 46,XX,der(9)t(9;16)(p23;q22) (case 2). Case 1 had primary hypogonadism (basal serum follicle stimulating hormone [FSH], 40.0 mIU/mL; leteinizing hormone [LH], 1.2 mIU/mL; estradiol [E2], <10 pg/mL), whereas case 2 had age-appropriate pubertal development (breast, Tanner stage 4; pubic hair, Tanner stage 3; menarche 11.7 years of age) and hormone values (FSH, 7.3 mIU/mL; LH, 6.7 mIU/mL; E2, 47 pg/mL). In addition, case 1 had hypoplastic labia majora, short distance between the vaginal orifice and the anus, and five renal cysts, and case 2 had anal atresia, short distance between the vaginal orifice and the anus, bilateral hydronephrosis of grade 3 with probable ureteropelvic junction stenosis, and renal dysfunction (serum creatinine, 1.52 mg/dL; urea nitrogen, 34.5mg/dL). Fluorescence in situ hybridization analysis for five regions and microsatellite analysis for 10 loci on 9p confirmed hemizygosity for the distal 9p region with the breakpoints between IFNA and D9S285 in case 1 and between D9S168 and D9S286 in case 2. The results, in conjunction with the previous data in XX patients with molecularly defined distal 9p monosomy, are consistent with the presence of a gene(s) involved in the development of indifferent gonad or subsequent ovarian differentiation in a approximately 11 Mb region distal to D9S168. In addition, it is possible that a gene(s) for anoperineal and renal development also maps distal to D9S168 and that for external genital development maps distal to D9S285 at the position approximately 16 Mb from the 9p telomere.
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Affiliation(s)
- Yoko Fujimoto
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, Tokyo, Japan
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Abstract
Estrogens have an essential role in the regulation of bone maturation and importantly in the closure of growth plates in both sexes. This prospective, randomized, placebo-controlled study was undertaken to evaluate whether suppression of estrogen synthesis in pubertal boys delays bone maturation and ultimately results in increased adult height. A total of 23 boys with constitutional delay of puberty (CDP) received a conventional, low-dose testosterone treatment for inducing progression of puberty. Eleven of these 23 boys were randomized to receive a specific and potent P450-aromatase inhibitor, letrozole, for suppression of estrogen action, and 12 boys were randomized to receive placebo. Estradiol concentrations in the letrozole-treated boys remained at the pretreatment level during the administration of letrozole, whereas the concentrations increased during the treatment with testosterone alone and during spontaneous progression of puberty. Testosterone concentrations increased in all groups, but during the letrozole treatment, the increase was more than fivefold higher than in the group treated with testosterone alone. The inhibition of estrogen synthesis delayed bone maturation. The slower bone maturation in the boys treated with testosterone and letrozole, despite higher androgen concentrations, than in the boys treated with testosterone indicate that estrogens are more important than androgens in regulation of bone maturation in pubertal boys. During the 18 months follow-up, an increase of 5.1 cm in predicted adult height was observed in the boys who received testosterone and letrozole, but no change was seen in the boys who received testosterone alone or in the untreated boys. This finding indicates that an increase in adult height can be attained in growing adolescent boys by inhibiting of estrogen action.
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Affiliation(s)
- Leo Dunkel
- Hospital for Children and Adolescents, University of Helsinki, PO Box 281, Helsinki 00029 HUS, Finland.
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Abstract
Turner syndrome (TS) is the most common chromosomal disorder causing short stature in females. The short stature is caused at least in part by haploinsufficiency of the short stature homeobox (SHOX) gene. Complete spontaneous puberty may occur in approximately 16% of patients, with spontaneous pregnancy in up to 4%. The final height of untreated TS girls is 86-88% of the mean adult female height. Growth hormone (GH) given alone or with oxandrolone improves final height. The major factors determining the outcome of GH therapy are the dose of GH used and the number of years of GH therapy prior to oestrogenization. Pubertal induction in TS should be individualized bearing in mind growth optimization and psychological issues. Adolescents and adults with TS may face a range of medical, fertility and psychosocial issues. Psychological support for TS individuals and families is important throughout life and should ideally be provided by both health professionals and TS support groups.
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Affiliation(s)
- Jennifer Batch
- Royal Children's Hospital, Herston, Brisbane, Queensland 4029, Australia
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16
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Plant TM. Neurobiological bases underlying the control of the onset of puberty in the rhesus monkey: a representative higher primate. Front Neuroendocrinol 2001; 22:107-39. [PMID: 11259134 DOI: 10.1006/frne.2001.0211] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this article is to discuss our understanding of the neurobiological mechanisms that govern the timing of the onset of puberty in the rhesus monkey, a representative higher primate, and, whenever possible, to place findings obtained from studies of this macaque in perspective with those for the human situation. Specifically, the dynamics in the postnatal ontogeny of hypothalamic GnRH gene expression and release are described, and the roles of neuropeptide Y and gamma-aminobutyric acid in imposing the restraint on pulsatile GnRH release during juvenile development are examined. Finally, the hypothesis that circulating leptin provides the signal that times the reaugmentation of pulsatile GnRH release at the termination of juvenile development, and therefore triggers the onset of primate puberty, is discussed.
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Affiliation(s)
- T M Plant
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA. plant1+@pitt.edu
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Abstract
An increase in pulsatile release of LHRH is essential for the onset of puberty. However, the mechanism controlling the pubertal increase in LHRH release is still unclear. In primates the LHRH neurosecretory system is already active during the neonatal period but subsequently enters a dormant state in the juvenile/prepubertal period. Neither gonadal steroid hormones nor the absence of facilitatory neuronal inputs to LHRH neurons is responsible for the low levels of LHRH release before the onset of puberty in primates. Recent studies suggest that during the prepubertal period an inhibitory neuronal system suppresses LHRH release and that during the subsequent maturation of the hypothalamus this prepubertal inhibition is removed, allowing the adult pattern of pulsatile LHRH release. In fact, y-aminobutyric acid (GABA) appears to be an inhibitory neurotransmitter responsible for restricting LHRH release before the onset of puberty in female rhesus monkeys. In addition, it appears that the reduction in tonic GABA inhibition allows an increase in the release of glutamate as well as other neurotransmitters, which contributes to the increase in pubertal LHRH release. In this review, developmental changes in several neurotransmitter systems controlling pulsatile LHRH release are extensively reviewed.
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Affiliation(s)
- E Terasawa
- Department of Pediatrics, Wisconsin Regional Primate Research Center, and University of Wisconsin-Madison, 53715-1299, USA.
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18
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Nathwani NC, Hindmarsh PC, Massarano AA, Brook CG. Gonadotrophin pulsatility in girls with the Turner syndrome: modulation by exogenous sex steroids. Clin Endocrinol (Oxf) 1998; 49:107-13. [PMID: 9797854 DOI: 10.1046/j.1365-2265.1998.00495.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES The endocrine manifestation of puberty, nocturnal pulsatile secretion of gonadotrophins precedes the physical manifestations by 2 years. Whether gonadal steroids and inhibin have a role to play in the regulation of pulsatile gonadotrophin release is unclear. The agonadal model, girls with Turner's syndrome (TS), has been used to determine the role of the hypothalamic pulse generator in the ontogeny of gonadotrophin secretion in man. We evaluated the ontogeny of gonadotrophin secretion in TS girls with respect to amplitude and frequency and compared these results to those obtained in a group of normal girls. The effects of treatment with ethinyloestradiol (EE2) or oxandrolone (OX) on parameters of gonadotrophin secretion were also evaluated. PATIENTS We studied 32 girls with TS, aged 4.3-12.4 years. All were prepubertal at the start of the study and longterm follow up revealed that none entered spontaneous puberty. The pulse amplitude and frequency was evaluated and compared to the results obtained in 23 normal girls, aged 4.9-12.8 years who acted as controls. MEASUREMENTS Samples were taken at 20 minute intervals for 24 h for the measurement of serum concentrations of luteinising (LH) and follicle stimulating (FSH) hormones. The girls were than randomized to receive EE2 or OX and were then re-admitted 6 months into the course of the treatment for a repeat 24 h serum profile of LH and FSH levels. RESULTS The girls with TS showed a clearly defined dominant pulse periodicity of 180 min and that in the normal cohort was 160-220 min. The girls with TS had an increased oscillatory activity between 120 and 260 min compared to the normal. Mean 24 h serum gonadotrophin concentration in TS girls was always higher than in the normal cohort. The inflection points of the fitted polynomial regression equation relating sex hormone concentration with age was similar for the two groups. EE2 lead to a significant change in pulse periodicity in TS girls but OX had no significant effect on the pulse periodicity. CONCLUSION These results demonstrate that girls with Turner syndrome have gonadotrophin pulse periodicity in the prepubertal years similar to those of normal girls. The oscillatory activity was much greater in girls with Turner syndrome at all ages in the prepubertal years, suggesting a role for the ovary in modulating gonadotrophin secretion in the prepubertal years. Our data confirm that in girls with Turner syndrome the normal pattern of gonadotrophin secretion evolving with time is preserved.
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Affiliation(s)
- N C Nathwani
- London Centre for Paediatric Endocrinology and Metabolism, Middlesex Hospital, London, UK
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19
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Abstract
The onset of puberty is a centrally driven process, the detailed mechanisms of which are not known. It is translated into an increased activity of the hypothalamic GnRH pulse generator. This in turn is seen as increased pituitary pulsatile secretion of LH and FSH. LH pulses are observed even in midchildhood, particularly after the onset of sleep. Onset of puberty is associated with a greater increase in LH pulse amplitude than frequency and a much greater increase in LH and FSH. A progressive increase in daytime pulsatility occurs, with a gradual reduction of sleep-entrained amplification. Prepubertal FSH concentrations are relatively high in girls, and continous ovarian follicular growth and atresia take place, with estradiol concentrations being higher than in boys. Only after the steep early pubertal increase in LH, ovarian steroidogenesis is activated, with increases in androgen and estrogen secretion. Under further FSH stimulation, follicular growth and maturation proceed. The first menstrual cycles are mostly anovulatory for 1 to 2 years. Luteal phase insufficiency is common the first five years after menarche.
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Affiliation(s)
- D Apter
- Department of Obstetrics & Gynecology, Helsinki University, Finland
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20
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Abstract
GnRH and its analogues have led to exciting new avenues of therapy in virtually every subspecialty of internal medicine as well as in gynecology, pediatrics, and urology. Since their discovery in 1971, it has been demonstrated that GnRH and its analogues enable medical professionals to influence the hypothalamic-pituitary-gonadal axis in two distinct classes of therapeutic applications. The first provides natural sequence GnRH in a pulsatile fashion via portable infusion pumps to mimic the normal physiology of hypothalamic GnRH secretion and restores reproductive potential to infertile men and women with disorders of endogenous GnRH secretion. The second mode uses long-acting GnRH agonists administered in a depot delivery to produce a paradoxical desensitization of pituitary gonadotropin secretion which, in turn, results in a complete ablation of the reproductive axis. This biochemical castration induced by GnRH agonist administration is a safe, effective, complete, and reversible method of removing the overlay of gonadal steroids from a variety of diseases which they are known to exacerbate. These diseases include endometriosis and uterine fibroids in women, prostate cancer in men, and precocious puberty in both sexes. This review examines the physiologic and pharmacologic principles underlying the advances produced by these agents, the mechanism of action of GnRH and its analogues at the cellular level, and the individual therapeutic applications to which these analogues have been applied. Because virtually every subspecialty of medicine will be touched by the GnRH analogues, this review provides an overview and background of their use.
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Affiliation(s)
- P M Conn
- Department of Pharmacology, University of Iowa College of Medicine, Iowa City 52242
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Bourguignon JP, Gérard A, Deby-Dupont G, Franchimont P. Effects of growth hormone therapy on the developmental changes of follicle stimulating hormone and insulin-like growth factor-I serum concentrations in Turner's syndrome. Clin Endocrinol (Oxf) 1993; 39:85-9. [PMID: 8348710 DOI: 10.1111/j.1365-2265.1993.tb01755.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE The aim was to investigate whether, in the absence of gonads, GH could bring forward the age of neuroendocrine activation resulting in onset of puberty. DESIGN In girls with Turner's syndrome, we evaluated the effects of GH therapy on developmental changes in FSH serum concentrations used as an indicator of neuroendocrine maturation in the absence of gonads. PATIENTS Thirty-nine girls with Turner's syndrome aged 4.0-17.1 years were treated using GH (25 IU/m2 week) for 1 year. MEASUREMENTS Serum levels of FSH and IGF-I were measured before initiation of GH therapy and 12 months later, after interruption of GH treatment for 2 days. RESULTS Pretreatment FSH levels were low between 6 and 10 years and increased markedly at 10-11 years of age. This pattern was unchanged after 1 year of GH therapy. Pretreatment IGF-I levels were positively correlated with age and they were uniformly increased after 1 year of GH therapy. CONCLUSIONS Our data suggest that GH and its effector, IGF-I, do not influence the timing of the onset of puberty through an effect on its neuroendocrine control.
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Chongthammakun S, Claypool LE, Terasawa E. Ovariectomy increases in vivo luteinizing hormone-releasing hormone release in pubertal, but not prepubertal, female rhesus monkeys. J Neuroendocrinol 1993; 5:41-50. [PMID: 8485542 DOI: 10.1111/j.1365-2826.1993.tb00362.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In pubertal, but not prepubertal, monkeys ovariectomy (OVX) results in an elevation of circulating luteinizing hormone (LH) levels. To determine if the castration-induced LH increase in pubertal monkeys is due to an increase in pulsatile LH-releasing hormone (LHRH) release, effects of OVX on in vivo LHRH release in the stalk-median eminence were examined in fully conscious monkeys using a push-pull perfusion method. The average ages (+/- SEM) of female rhesus monkeys in each group at OVX were 14.5 +/- 0.6 months (n = 6; prepubertal), 25.0 +/- 1.3 months (n = 5; early pubertal) and 37.8 +/- 2.1 months (n = 6; midpubertal). Perfusate samples from the stalk-median eminence were obtained in 10-min fractions for 6 h in the morning (0600 to 1200 h) and 6 h in the evening (1800 to 2400 h), from the same subjects before OVX, and at 29 days and approximately 100 days after OVX. LHRH levels in perfusates were measured by radioimmunoassay. LH levels throughout the experiment were monitored by periodic blood sampling. OVX resulted in a significant LH increase in early and midpubertal monkeys (P < 0.001 for both), but not in prepubertal monkeys. Similarly, OVX in early and midpubertal monkeys increased mean LHRH release when examined 29 days after surgery (P < 0.05 and P < 0.01, respectively). The OVX-induced LHRH increases in early and midpubertal monkeys remained elevated at approximately 100 days postcastration. Furthermore, it was found that effects of OVX on the increased LHRH release were primarily due to the elevation of basal release and pulse amplitude, but not pulse frequency. In contrast, OVX did not cause any significant effects on pulsatile LHRH release in prepubertal monkeys. The results indicate that an increase in LHRH release and a concomitant increase in circulating LH occurs after OVX in pubertal monkeys, but not in prepubertal monkeys. These data are consistent with the hypothesis that the low level of LH in circulation before the onset of puberty is due to a low amount of LHRH release which is independent of ovarian steroid feedback and that the maturity of the neuronal control system for the pulsatile LHRH release is responsible for the onset of puberty. After the onset of puberty, the negative feedback of ovarian steroid hormones becomes important to the regulation of gonadotropin release.
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Bennet A, Lacaze JC, Caron P, Berrada R, Barbe P, Louvet JP. Correlations between mean LH levels and LH pulse characteristics: differences between normal and anovulatory women. Clin Endocrinol (Oxf) 1991; 35:431-7. [PMID: 1814658 DOI: 10.1111/j.1365-2265.1991.tb03561.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Since LH secretion occurs as a series of pulses, relationships between mean LH levels and LH pulse characteristics are to be expected. The aim of this study was to determine whether such relationships are similar in normal women and anovulatory patients. DESIGN We studied the correlations between mean LH levels and the products amplitude x frequency and area x frequency of LH pulses in normal women and in patients with disorders of ovulation. Blood samples were taken from each subject every 10 minutes during 6 hours on the 8th day after the last menses. PATIENTS The patients were divided into three groups: patients with polycystic ovary syndrome (n = 11), patients with idiopathic anovulation (n = 14) and patients with short luteal phase (n = 13). Their results were compared to those of 12 normal women. MEASUREMENTS LH was evaluated with an immunoradiometric assay. LH data were analysed with a 3 standard deviation threshold criterion for significant peaks, and with cluster analysis algorithm using 1, 2.5 and 5% false positive error rates and 'optimal parameters' (which give less than 5% false positive and false negative error rates in LH male data). RESULTS Highly significant correlations between amplitude x frequency, area x frequency and mean LH were found in normals and patients with short luteal phase; no significant correlation was found in patients with polycystic ovary syndrome, while significant correlations were found in patients with idiopathic anovulation only with some of our criteria for peak detection. CONCLUSION The differences that we found between the groups suggest that when commonly used methods are employed to determine LH pulse characteristics, most of the significant LH pulses are taken into account in normals and patients with short luteal phase, but not in anovulatory patients, especially in patients with polycystic ovary syndrome. This method using two correlations appears to be a simple and useful way to show the differences in the mechanisms by which mean LH levels are achieved in normal subjects and patients.
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Affiliation(s)
- A Bennet
- Service d'Endocrinologie, CHU Toulouse-Purpan, France
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Affiliation(s)
- P M Conn
- Department of Pharmacology, University of Iowa College of Medicine, Iowa City 52242-1109
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Wennink JM, Delemarre-van de Waal HA, Schoemaker R, Schoemaker H, Schoemaker J. Luteinizing hormone and follicle stimulating hormone secretion patterns in girls throughout puberty measured using highly sensitive immunoradiometric assays. Clin Endocrinol (Oxf) 1990; 33:333-44. [PMID: 2123756 DOI: 10.1111/j.1365-2265.1990.tb00498.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pulsatile gonadotrophin secretion patterns were studied in 36 healthy girls by measuring every 10 min and applying immunoradiometric assays (IRMA). Different stages of puberty were associated with significant changes in the plasma LH and FSH levels, pulse numbers (Pno) and pulse amplitudes (pA). Plasma LH was not detectable by day or night in young prepubertal girls (B1), neither was plasma oestradiol (E2); however, plasma FSH was detectable in a pulsatile pattern. In the older prepubertal girls (B1-onset) a discrete pulsatile LH pattern became detectable only during the night; plasma FSH tended to rise, while E2 became just detectable. In the early pubertal girls (B2) most daytime LH values were above the detection limit, in some with low-amplitude pulses. At night, pulses with a wide range of pulse amplitudes were detected. Plasma FSH increased further, plasma E2 only slightly. With the progression of puberty the plasma LH and FSH levels, Pno and pA increased significantly from stage B2 to B3 during the day (P less than or equal to 0.05) and close to significance during the night (0.05 less than or equal to P less than or equal to 0.1). However, in stage B4 the secretory characteristics tended to decline, while from stage B3 onwards plasma E2 started to rise rapidly (P less than or equal to 0.05, during the night from stage B2 to B3, during the day from B3 to B4m-). Simultaneous LH and FSH pulses were observed throughout puberty, usually during the night. Using these IRMA methods nocturnal LH in older prepubertal girls and both diurnal and nocturnal FSH pulsatility could be demonstrated in young prepubertal girls. From this study we conclude that (1) puberty in girls, as in boys, may be brought about by an increasing GnRH secretion both in frequency and amplitude, first appearing during the night. This increased GnRH stimulation results in LH secretion only during the night; (2) a cyclical pulsatile LH pattern including an LH surge can be established before the menarche; the capacity for positive feedback activity is not the final maturation characteristic to achieve an ovulatory menstrual cycle.
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Affiliation(s)
- J M Wennink
- Department of Pediatrics, Academic Hospital, Vrije Universiteit, Amsterdam, The Netherlands
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Maxwell M, Karacostas D, Ellenbogen RG, Brzezinski A, Zervas NT, Black PM. Precocious puberty following head injury. Case report. J Neurosurg 1990; 73:123-9. [PMID: 2352013 DOI: 10.3171/jns.1990.73.1.0123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A 6-year-old girl developed secondary sexual characteristics 5 months after severe closed head injury. Endocrinological tests confirmed a pubertal sexual condition; there was also diminution of serum melatonin and disruption of the diurnal pattern. Magnetic resonance imaging demonstrated focal hypothalamic injury; this is believed to be the first time such a posttraumatic lesion has been demonstrated by imaging techniques. The pathophysiology of this condition is discussed.
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Affiliation(s)
- M Maxwell
- Neurosurgical Service, Massachusetts General Hospital, Brigham and Women's Hospital, Boston
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Talbot JA, Shalet SM, Tsatsoulis A, Grabinski M, Robertson WR. Luteinizing hormone pulsatility in men with damage to the germinal epithelium. INTERNATIONAL JOURNAL OF ANDROLOGY 1990; 13:223-31. [PMID: 2387642 DOI: 10.1111/j.1365-2605.1990.tb00980.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bioactive-LH (B-LH) was measured in plasma by in-vitro bioassay and immunoactive-LH (I-LH) by immunoassay at 10 min intervals for 6 h in five men after standard chemotherapy for Hodgkin's disease. Eleven normal men acted as controls. Follicle-stimulating hormone (FSH) was markedly raised in the treated patients (mean +/- SEM; 12.8 +/- 2.8 vs. 2.7 +/- 0.4 IU l-1, P less than 0.006) reflecting damage to the germinal epithelium. Bioactive (27.4 +/- 2.8 vs. 12.9 +/- 1.3 IU l-1) and I-LH (9.6 +/- 2.0 vs. 4.9 +/- 0.4 IU l-1) were elevated (P less than 0.006) in the patient group whilst testosterone levels (24.0 +/- 3.8 vs. 19.6 +/- 2.4 nmol l-1) were normal. The testosterone I-LH ratio, a putative index of Leydig cell dysfunction, was negatively correlated with FSH levels (r = -0.85, P less than 0.02). Bioactive and I-LH pulse peak amplitude were elevated, as were pulse maxima (P less than 0.05). In contrast, B-LH pulse frequency was similar between the patients (2 pulses per 6 h) and controls (median 2, range 1-3 pulses per 6 h) as was the I-LH pulse frequency (median 2, 1-2 pulses per 6 h in both groups). The mean B:I LH ratios were similar (2.94 +/- 0.09 vs. 2.63 +/- 0.14) in both groups, although the inter-pulse B:I ratio was increased (P less than 0.007) in the patient group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J A Talbot
- Department of Medicine (Clinical Biochemistry), University of Manchester, Hope Hospital, Salford, U.K
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Ogata T, Matsuo N, Shimizu N. A ring X chromosome, 46,Y,r(X)(p22.33q28), as a cause of extreme short stature in a male. AMERICAN JOURNAL OF MEDICAL GENETICS 1990; 35:241-4. [PMID: 2106786 DOI: 10.1002/ajmg.1320350219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We describe a 15 10/12-year-old boy (Tanner stage 4, peak growth velocity 7 cm/year) with a ring X chromosome who presented with extreme short stature (mean -5.3 SD) as the sole recognizable abnormality. His chromosome constitution was determined to be 46,Y,r(X)(p22.33q28) in 174 of 182 peripheral blood cells and in 35 skin fibroblasts. Of the remaining eight peripheral blood cells, five had a dicentric double-size ring and three had a smaller ring. Other laboratory studies for short stature were noncontributory. We suspect that the ring's specific behavior in mitosis or its effect on expression of the statural determinant on the X chromosome short arm may be responsible for short stature in this patient.
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Affiliation(s)
- T Ogata
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
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30
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Usala AL, Blumer JL. Pharmacology of new hormonal therapies in the treatment of pediatric endocrine disorders. Pediatr Clin North Am 1989; 36:1157-82. [PMID: 2571972 DOI: 10.1016/s0031-3955(16)36763-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Advances in genetic engineering will make possible treatment of many pediatric endocrine disorders with replacement therapy. Some of these conditions include short stature, precocious puberty, and diabetes mellitus. Although the availability of such hormonal replacement offers new treatment modalities, an understanding of their mechanism of action and pharmacologic characteristics is crucial to maximize their effectiveness while minimizing possible untoward effects. The clinician must evaluate potential risks and benefits as these substances come to market without definitive answers being available as to their long-term effects.
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Affiliation(s)
- A L Usala
- Department of Pediatrics, Saint Luke's Hospital, Cleveland, Ohio
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31
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Van Cauter E. Estimating false-positive and false-negative errors in analyses of hormonal pulsatility. THE AMERICAN JOURNAL OF PHYSIOLOGY 1988; 254:E786-94. [PMID: 3377077 DOI: 10.1152/ajpendo.1988.254.6.e786] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previous studies evaluating computer algorithms for endocrine pulse detection have estimated the rate of false-positive pulses in series of purely random variations (i.e., "noise") and have determined pulse-detection criteria associated with low levels of such false-positive rates. The present study investigates the relationship between the false-positive rate and the sizes of the false-positive and false-negative errors on pulse frequency for series including both pulses and noise. The algorithm used (ULTRA) proceeds by eliminating all peaks of concentration for which either the increment or the decrement does not exceed a threshold expressed in multiples of the local intra-assay coefficient of variation. A total of 336 computer-generated series was analyzed using thresholds of two and three coefficients of variation. The effects of noise level, pulse frequency, pulse amplitude, and presence of a base-line variation on the sizes of the false-positive and false-negative errors were evaluated. The false-positive rate in noise series exceeded the false-positive rate by a 4- to 10-fold factor in series including at least 8 pulses/100 samples. When pulse frequency increased, the false-positive error decreased, but the false-negative error increased. In series with more than 8 pulses/100 samples, the use of thresholds aimed at maintaining the false-positive rate in noise series below 1% resulted in a false-negative error in excess of 20%. In conclusion, for hormonal profiles that include 8 or more pulses/100 samples, the use of pulse-detection criteria tailored to minimize the false-positive rate in noise series may result in an underestimation of pulse frequency.
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Affiliation(s)
- E Van Cauter
- Institute of Interdisciplinary Research, Free University of Brussels, Belgium
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Spratt DI, Crowley WF. Pituitary and gonadal responsiveness is enhanced during GnRH-induced puberty. THE AMERICAN JOURNAL OF PHYSIOLOGY 1988; 254:E652-7. [PMID: 3129946 DOI: 10.1152/ajpendo.1988.254.5.e652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We hypothesized that the hypothalamic gonadotropin-releasing hormone (GnRH) signal that initiates sexual maturation is further amplified at both the pituitary and gonadal levels during puberty. To test this theory, six GnRH-deficient men were monitored during administration of exogenous GnRH at a physiological frequency for greater than or equal to 9 mo. GnRH doses were progressively increased until normal testosterone (T) concentrations and secondary sexual development were achieved. This "optimized" dose of GnRH was then sustained for at least 6 mo to allow maturation of the hypothalamic-pituitary-gonadal axis. The GnRH dose was then progressively decreased to a level that had been unable to stimulate normal T secretion before sexual maturation. Changes in pituitary responsiveness were analyzed in four of the six men by comparing gonadotropin responses to identical doses of GnRH before and after sexual maturation. Mean serum luteinizing hormone and follicle-stimulating hormone levels as well as luteinizing hormone pulse amplitudes were greater after the induction of sexual maturation than before despite identical doses of GnRH. Both pituitary and gonadal responsiveness was then analyzed in the remaining two subjects by choosing periods of evaluation where endogenous gonadotropin levels were matched before and after the period of sexual maturation. Serum T concentrations were greater after sexual maturation than before despite equivalent gonadotropin input to the testes and LH pulse amplitudes. Thus the testicular responsiveness to gonadotropins increased during sexual maturation. After initiation of puberty by GnRH secretion, amplification at both the pituitary and gonadal levels contributes to sexual maturation in the human.
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Affiliation(s)
- D I Spratt
- Reproductive Endocrine Unit, Vincent Memorial Research Laboratories, Massachusetts General Hospital, Boston 02114
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Marshall JC, Kelch RP. Gonadotropin-releasing hormone: role of pulsatile secretion in the regulation of reproduction. N Engl J Med 1986; 315:1459-68. [PMID: 3097540 DOI: 10.1056/nejm198612043152306] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Veldhuis JD, Rogol AD, Johnson ML. Minimizing false-positive errors in hormonal pulse detection. THE AMERICAN JOURNAL OF PHYSIOLOGY 1985; 248:E475-81. [PMID: 3985145 DOI: 10.1152/ajpendo.1985.248.4.e475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To explore the problem of type I (false-positive) statistical errors associated with enumerating endocrine pulses, we used the analysis of immunoactive luteinizing hormone (LH) pulses as a paradigm. In this system, the distribution of measurement error was found to approximate a Gaussian pattern. Moreover, the choice of a fixed threshold criterion to identify a hormone pulse (as generally undertaken to date) was shown to yield significantly different false-positive error rates under different experimental conditions. Therefore, we developed a technique to minimize the detection of false-positive signals and to maintain an essentially uniform error rate among different experimental groups. This simple technique requires that the pulse-detection threshold be adjusted in relation to the degree of intra-assay measurement error present. Our method should facilitate the valid comparison of endocrine pulse frequencies in normal physiological states vs. those associated with hormonal deficiency when measurement error is typically greater. In addition, this approach will aid in a more meaningful assessment of pulse concordance between two or more different hormonal species (i.e., in different assays) and will assist in comparisons of pulse properties quantitated in different laboratories. In summary, rates of false-positive pulse detection using conventional fixed-threshold criteria are materially influenced by even small differences in within-assay variance. We present a technique to minimize this type I statistical error and to maintain an essentially uniform error rate among different experimental groups.
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Veldhuis JD, Evans WS, Rogol AD, Drake CR, Thorner MO, Merriam GR, Johnson ML. Performance of LH pulse-detection algorithms at rapid rates of venous sampling in humans. THE AMERICAN JOURNAL OF PHYSIOLOGY 1984; 247:E554-63. [PMID: 6496672 DOI: 10.1152/ajpendo.1984.247.4.e554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
To assess the influence of the sampling rate on the quantitative characterization of pulsatile luteinizing hormone (LH) release, we withdrew blood at 4-min intervals for 8 h in five men and at 1-min intervals for 2 h in six other men. For comparative purposes, significant LH pulses were enumerated by three independent, computerized pulse-detection algorithms currently available. Our results indicate that, although the absolute number of LH pulses detected was influenced by the particular algorithm used and the estimate of intra-assay variance, all three analyses yielded increased pulse-frequency estimates at more intensive rates of venous sampling. Moreover, using a fourth, modified pulse-detection algorithm intended to maximize recognition of true-positive LH pulses while minimizing both false-positive and false-negative pulses, we observed that venous sampling at 4- and 1-min intervals exposed 4- and 12-fold more LH pulses, respectively, than could be discerned at conventional sampling rates. At rapid rates of venous sampling, the pattern of LH pulses comprised high-frequency, low-amplitude LH pulsations superimposed on lower-frequency LH peaks. This pattern suggests that the pituitary gland is responsive to high rates of intermittent neural stimulation. Moreover, these observed profiles are consistent with rapid initial rates of LH disappearance and/or distribution that we could demonstrate after intravenous bolus injections of purified LH in hypogonadotropic volunteers. In conclusion, we have compared results from three different pulse-detection algorithms at various rates of venous sampling and demonstrated a critical influence of sampling rate on apparent LH pulse frequency in humans.
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