Regulation of puberty

Children's odor pleasantness ratings may not differ according to pubertal status: Preliminary results from a sample of 11-14-year-old Czech children

Puberty tends to be viewed as a "turning point" in hedonic perception of body odor (BO)-related smells. The pubertal stage, a potential proxy for the underlying physiological changes, may contribute to variation in odor hedonic perception. Other potential modulators of odor hedonics are general semantic knowledge about odors (which also tends to be subsumed under the term "age") and perceived odor intensity. The present cross-sectional study examined differences in hedonic odor perception across puberty in 205 Czech children aged 11-14 (89 boys). We investigated whether children differ in the hedonic appraisal of BO-related (16-androstenes and castoreum control), but also food and non-food odors according to their pubertal (penis/breast and pubic hair) development and general semantic knowledge about odors (operationalized as odor identification), controlling for age and perceived odor intensity. As a subsidiary aim, we examined variation in odor identification. We asked the children to self-stage themselves using drawings depicting Tanner's penis/breast and pubic hair stages of pubertal development, estimated their general semantic knowledge about odors with a Sniffin' Sticks identification test, and obtained their pleasantness and intensity ratings of body odor-related, food, a non-food smells. We found that the participants' ratings of the 16-androstenes and those of the perceptually similar odor of castoreum differed according to perceived intensity and, in the latter case, in boys vs. girls as well, but there were no influences of pubertal status or odor identification on the perceived pleasantness. Similarly, hedonic appraisal of non-food (but not food) odors was only influenced by perceived intensity. Regarding odor identification, differences between boys and girls were limited to younger children and did not become more marked throughout puberty. Perceived pleasantness of odors, irrespective of whether they are associated with body smells, food, or other, does not appear to vary across puberty, and boys and girls seem to achieve similar levels of semantic odor knowledge as they grow up.

Syrian national growth references for children and adolescents aged 2-20 years

Background

During the past three decades, growth charts have become one of the principal tools for monitoring anthropometric development in individuals and populations as well. Growth references by the CDC and other countries have been widely used in our hospitals and healthcare units for clinical assessment of children’s development. The apparent overestimation and underestimation of many children's anthropometrics indicated the need to construct our own references. The objective of this study is to establish the national growth references for the Syrian population 2–20-year-old.

Methods

A multicenter cross-sectional sample of 13,548 subjects, aged 2–20 years, were recruited from various kindergartens, schools, and universities across the Syrian Arab Republic between February and May-2019. Response variables (stature, weight, and BMI) were fitted against age using P-splines and three empirical distributions: Box-Cox T, Box-Cox Power Exponential, and Box-Cox Cole and Green. Residuals diagnostic Q-tests and worm plots were used to check the validity of fitted models.

Results

Box-Cox T provided the best fit for stature-for-age, whereas Box-Cox Power Exponential provided the best fit for weight-for-age and BMI-for-age. Residuals diagnostics revealed adequate models fitting. BMI cutoffs revealed an increased prevalence of obesity (4.5% and 3.66%) and overweight (20.1% and 19.54%), for boys and girls respectively, in our population.

Conclusions

Growth charts are available for use now in our hospitals and healthcare units. For 0–2-year-old children, we recommend using the World Health Organization’s standards.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03331-0.

Transition From Diencephalic Syndrome to Hypothalamic Obesity in Children With Suprasellar Low Grade Glioma: A Case Series

BACKGROUND

Children with suprasellar low grade glioma (LGG) frequently develop problems to maintain their body weight within the normal range, due to hypothalamic dysfunction. Hypothalamic damage may result in the diencephalic syndrome (DS), characterized by underweight or failure to thrive, but also in hypothalamic obesity (HO). Children with LGG presenting with DS at young age often develop HO later in life. The underlying pathophysiology for this change in body mass index (BMI) is not understood. Previous hypotheses have focused on the tumor or its treatment as the underlying cause. To better understand its etiology, we aimed to relate changes in BMI over time in children with suprasellar LGG presenting with DS to age, tumor progression, treatment, and endocrine function. We hypothesize that the development of HO in children with LGG presenting with DS is related to maturation status of the hypothalamus at time of injury and thus age.

METHODS

In this retrospective case series, all cases diagnosed in the Netherlands with suprasellar located LGG, currently treated or followed, with a history of DS developing into HO were included.

RESULTS

In total, 10 children were included. Median age at LGG diagnosis was 1.5 years (range 0.4-5.5), median BMI SDS was -2.64. The children developed overweight at a median age of 4.5 years (2.2-9.8). The median total difference in BMI SDS between underweight and obesity was +5.75 SDS (4.5-8.7). No association could be found between transition of DS to HO and onset of a pituitary disorder (present in 70.0%), surgery, chemotherapy, or tumor behavior. Two had developed central precocious puberty (CPP), both while having underweight or normal weight.

CONCLUSION

The shift from DS to HO in children with hypothalamic LGG may be associated with age and not to tumor behavior, treatment characteristics or pituitary function. The development of CPP in these children seems not to be related to obesity. Our findings may indicate that the clinical picture of hypothalamic dysfunction reflects the maturation state of the hypothalamus at time of lesioning. Future prospective studies are needed to better understand underlying causative mechanisms of the morbid changes in body weight.

Kisspeptin Levels in Girls with Precocious Puberty: A Systematic Review and Meta-Analysis

BACKGROUND/AIMS

Kisspeptin (KP) is a key player in the regulation of the release of gonadotropin-releasing hormone (GnRH), which increases the secretion of gonadotropin during puberty to establish reproductive function and regulate the hypothalamic-pituitary-gonadal axis. Premature activation of GnRH secretion leads to idiopathic/central gonadotropin-dependent precocious puberty (CPP). We aimed to compare the blood KP concentrations in girls with CPP and healthy controls.

METHODS

A systematic review and meta-analysis was performed. We searched MEDLINE, EMBASE, The Cochrane Library, and SciELO. Random-effects model and standardized mean difference (SMD) were used. Heterogeneity was assessed through I2. Meta-regression considered patient age, KP fraction, and analytical method for KP measurement.

RESULTS

The 11 studies included comprised 316 CPP patients and 251 controls. Higher KP levels in the CPP group were found (SMD 1.53; CI 95% = 0.56-2.51). Subgroup analysis revealed association with patient age (p = 0.048), indicating a positive correlation between elevation in KP concentration and age in CPP group. A group of patients with precocious thelarche (PT) from 5 of the included studies comprising 121 patients showed higher levels of KP (1.10; -0.25-2.45: CI 95%) and high heterogeneity (I2 = 91%). The CPP/PT ratio for KP level indicates KP 36% higher on CPP than PT patients.

CONCLUSIONS

A consistent difference in KP levels between girls with CPP and controls was identified. While there are important limitations in KP assays which argue against its use as a diagnostic tool, the KP levels in CPP versus control and PT children are consistent with the predicted mechanisms and pathophysiology of CPP.

Biological clock and heredity in pubertal timing: what is new?

Puberty represents a milestone during a person's life and is characterized by several physical and psychological changes which end with the achievement of sexual maturation and of fertility. Puberty onset depends on a series of sophisticated, not completely understood, mechanisms certainly involving Gonadotropin-Releasing Hormone (GnRH) and its effects on pituitary gonadotropins. As recent evidence has demonstrated that pubertal timing deeply affects future adult health life, much efforts have been performed in order to clarify the exact actors involved in the onset and progression of puberty. Genetic factors are undoubtedly essential players in the regulation of pubertal development, accounting for approximately 50-80% of its variability. Mutations in genes such as KISS1, MKRN3 and DLK1 have been associated with central precocious puberty. Interestingly, a possible involvement of epigenetic mechanisms has been proposed as additional element able to affect pubertal phase. Environmental factors have recently attracted much attention. Indeed, an overall decrease in the age of puberty has been observed in the last decades. As genetic factors require long time to exert their effect, other players, such as environmental ones, may be involved. Special focus has been posed on nutritional status, endocrine-disrupting chemicals with non-conclusive results. Pubertal timing deeply affects future life, suggesting the need to clarify mechanisms driving pubertal onset and progression, in order to identify tailored therapeutic strategies and targets.

The relationship between body weight and dietary habits with respect to the timing of puberty among saudi children and adolescents

Objective

The objective is to investigate the timing of pubertal onset as determined by the development of secondary sexual characteristics in relation to body weight and dietary patterns among Saudi females.

Methods

Children/adolescents visiting general and endocrinology pediatric clinics in King AbdulAziz University Hospital were invited to participate in this study. Female subjects between the ages of 5 and 20 years were included in this study, and those with syndromic disease, chronic comorbidities, endocrinopathies, organic causes of precocious puberty, positive family history of early pubertal onset, and under chronic medication were excluded from the study. Data were collected through clinical interviews with the consent of the legal guardians, and physical examinations were conducted.

Results

A.

total of 164 females were investigated. The mean age of thelarche, adrenarche, and menarche was 10, 11.3, and 12.2 years, respectively. We found a significant correlation between higher weight standard deviation and an earlier age of both thelarche and adrenarche. In addition, daily consumption of fast foods was significantly associated with an earlier menarchal age. Consumption of nonorganic poultry was linked to early thelarche.

Conclusion

Efforts should be directed to increase public and community awareness that fast food consumption, inorganic poultry, and higher body weight are important modifiable factors that lead to an earlier onset of female puberty across different parameters: breast development, adrenarche, and menstruation.

Review of the Literature on Current Changes in the Timing of Pubertal Development and the Incomplete Forms of Early Puberty

Puberty is a sensitive period of life characterized by the appearance of secondary sex characteristics which leads to a complete sexual maturation. It physiologically starts between the age of 8 and 13 years in girls and 9 and 14 years in boys. In the last two decades, several studies have showed that start of puberty has moved up to younger ages by 12-18 months, and some of the hypotheses trying to explain this change include the role of nutritional status and obesity and the influence of extrinsic factors such as exposure to endocrine-disrupting chemicals (EDCs), as well. The hypothalamic-hypophysis-gonadal axis develops during embryogenesis, and except for a period of activation immediately after birth, remains suppressed until the onset of pubertal development. At the beginning of puberty, the pulse generator is reactivated, probably due to progressive stimulatory influences on GnRH neurons from glial signals and neurotrasmitters. Kisspeptin and its receptor play a fundamental role in this phase. Premature Pubarche/Adrenarche, Premature Thelarche, and Premature Menarche are incomplete forms of precocious pubertal development that have their origin in endocrine mechanisms that only recently have started to be understood. It is important to distinguish these forms from the complete ones in order to reassure patients and parents about the non-evolution of pubertal progression and avoid non-useful treatments with analogous LHRH.

Body Image Dissatisfaction and the Adrenarchal Transition

BACKGROUND

Puberty marks a transition in risk for body image disturbance and disordered eating. Yet few studies have examined these symptoms across puberty and none have examined links with adrenarche, the earliest phase in the pubertal hormonal cascade.

METHOD

Levels of adrenal androgens (dehydroepiandrosterone, dehydroepiandrosterone sulphate, and testosterone) were measured in a population-based study of 8- to 9-year-old children (516 males and 621 females). Body dissatisfaction was measured using the Kids' Eating Disorder Scale Silhouettes. Covariates included body mass index, age, and socioeconomic status.

RESULTS

There were significant associations between adrenal androgen levels and greater body dissatisfaction in both males and females. Specifically, females with more advanced levels of dehydroepiandrosterone and testosterone relative to peers, and males with more advanced levels of testosterone relative to peers, reported greater body dissatisfaction. However, after adjusting for covariates, hormones levels were no longer associated with body dissatisfaction, and only higher body mass index had a clear association with body dissatisfaction.

CONCLUSIONS

The adrenarchal transition brings a heightened risk for body dissatisfaction. Whether this arises from the neuroendocrine effects of adrenal androgens or as a reaction to the greater body mass that accompanies adrenarche requires further exploration.

Group housing during adolescence has long-term effects on the adult stress response in female, but not male, zebra finches (Taeniopygia guttata)

Adolescent social interactions can have long-term effects on physiological responses to stressors in later-life. A larger adolescent group size can result in higher stressor-induced secretion of glucocorticoids in adulthood. The effect may be due to a socially-mediated modulation of gonadal hormones, e.g. testosterone. However, group size (number of animals) has been conflated with social density (space per animal). Therefore it is hard to determine the mechanisms through which adolescent group size can affect the stress response. The current study aimed to tease apart the effects of group size and social density during adolescence on the physiological stress response and gonadal hormone levels in adulthood. Adolescent zebra finches were housed in groups varying in size (2 vs. 5 birds per cage) and density (0.03m³ vs. 0.06m³ per bird) during early adolescence (day 40-60). Density was only manipulated in birds raised in groups of five. Glucocorticoid concentration secreted in response to a standard capture and restraint stressor was quantified in adolescence (day 55±1) and adulthood (day 100+). Basal gonadal hormone concentrations (male testosterone, female estradiol) were also quantified in adulthood. Female birds housed in larger groups, independent of social density, secreted a higher glucocorticoid concentration 45min into restraint regardless of age, and had higher peak glucocorticoid concentration in adulthood. Adult gonadal hormone concentrations were not affected by group size or density. Our results suggest that group size, not density, is a social condition that influences the development of the endocrine response to stressors in female zebra finches, and that these effects persist into adulthood. The findings have clear relevance to the social housing conditions necessary for optimal welfare in captive animals, but also elucidate the role of social rearing conditions in the emergence of responses to stressors that may persist across the lifespan and affect fitness of animals in wild populations.

Species Comparison of Postnatal Development of the Female Reproductive System

The postnatal development of the female reproductive system in laboratory animals and humans is reviewed. To enable a meaningful species comparison of the developing female reproductive system, common definitions of developmental processes were established with a focus made on aspects that are similar across species. A species comparison of the key endocrine, morphologic, and functional (onset of ovarian cycles and ability to reproduce) features of postnatal development of the female reproductive system is provided for human, nonhuman primate, dog, rat, and also mouse, minipig, and rabbit where possible. Species differences in the timing and control of female sexual maturation are highlighted. Additionally, a species comparison of the type and timing of female reproductive ovarian cycles was compiled. Human development provided the frame of reference, and then other common laboratory species were compared. The comparison has inherent challenges because the processes involved and sequence of events can differ greatly across species. Broad strokes were taken to assign a particular average age to an event and are to be used with caution. Methods of evaluation of postnatal female reproductive development in laboratory animals are discussed. Lastly, control rodent data from one of the author's laboratory on vaginal opening, first estrus, estrous cyclicity, and the histopathology involved with the developing female rat and mouse are presented. The information provided in this review is intended to be a resource for the design and interpretation of juvenile animal toxicity testing and ultimately, the relevance of the data to characterize potential risks for women and girls. Birth Defects Research 110:163-189, 2018. © 2017 Wiley Periodicals, Inc.

Alteration of Mammary Gland Development and Gene Expression by In Utero Exposure to Cadmium

Environmental exposure to estrogens and estrogen like contaminants during early development is thought to contribute to the risk of developing breast cancer primarily due to an early onset of puberty; however, exposure during key developing windows may also influence the risk of developing the disease. The goal of this study was to ask whether in utero exposure to the metalloestrogen cadmium alters mammary gland development due to acceleration of puberty onset or to an effect on early development of the mammary gland. The results show that, in addition to advancing the onset of puberty, in utero exposure to the metalloestrogen cadmium altered mammary gland development prior to its effect on puberty onset. In utero exposure resulted in an expansion of the number of mammosphere-forming cells in the neonatal mammary gland and an increase in branching, epithelial cells, and density in the prepubertal mammary gland. In the postpubertal mammary gland, there was a further expansion of the mammary stem/progenitor cell population and overexpression of estrogen receptor-alpha (ERα) that was due to the overexpression and altered regulation of the ERα transcripts derived from exons O and OT in response to estradiol. These results suggest that in utero exposure to cadmium increases stem/progenitor cells, cell density, and expression of estrogen receptor-alpha that may contribute to the risk of developing breast cancer.

The effects of estradiol on mood and behavior in human female adolescents: a systematic review

Mood disorders and health risk behaviors increase in adolescence. Puberty is considered to contribute to these events. However, the precise impact of pubertal hormone changes to the emergence of mood disorders and risk behaviors is relatively unclear. It is important that inappropriate attribution is not made. Our aim was to determine what is known about the effect of endogenous estradiol on human adolescent girls' mood and behavior. The databases searched were MEDLINE, Embase, PsycINFO, Education Resources Information Center (ERIC), Pre-MEDLINE, Web of Science, and Scopus for all dates to October 2014. For inclusion, contemporaneous hormone and mood or behavioral assessment was required. Data were extracted following a template created by the authors. Fourteen studies met our inclusion criteria. There was some consistency in findings for mood and estradiol levels, with associations between estradiol and depression and emotional tone and risk taking. Results were less consistent for studies assessing other mood and behavioral outcomes. Most studies were cross-sectional in design; assay methodologies used in older studies may lack the precision to detect early pubertal hormone levels.

CONCLUSION

Three longitudinal and several cross-sectional studies indicate potential associations between estradiol and certain mood or affective states, especially depression and mood variability though there are insufficient data to confirm that the rise in estradiol during puberty is causative. We believe that it is important for health professionals to take care when attributing adolescent psychopathology to puberty hormones, as the current data supporting these assertions are limited.

The response to gonadotropin releasing hormone (GnRH) stimulation test does not predict the progression to true precocious puberty in girls with onset of premature thelarche in the first three years of life

CONTEXT

Premature thelarche in early childhood may evolve into true precocious puberty. The individuation of cases progressing to precocious puberty is challenging.

OBJECTIVE

We analyzed the parameters predictive for progression in girls younger than 3 years.

DESIGN AND SETTING

We conducted a retrospective longitudinal study.

PATIENTS AND METHODS

A total of 450 girls referred for premature thelarche were initially evaluated, 353 were clinically monitored at 3-month intervals, and 97 underwent endocrine and imaging assessment. Central precocious puberty (CPP) was diagnosed in girls showing LH peak response to GnRH testing >5 mU/mL with tuber cinereum hamartoma at magnetic resonance imaging, or with normal magnetic resonance imaging but progression of puberty during follow-up.

MAIN OUTCOME MEASURE

We measured the progression to precocious puberty.

RESULTS

Idiopathic premature thelarche (IPT) was diagnosed in 85 of the 97 girls who underwent extensive evaluation, CPP in nine girls, and peripheral precocious puberty in three girls. The uterus was >34 mm in six (7%) IPT girls and six (66.6%) CPP girls. Basal LH was >0.2 mU/mL in one (1.17%) IPT girl and eight (88.8%) CPP girls. LH peak was >5 mU/mL in 31 (36.4%) IPT girls and nine (100%) CPP girls. LH peak/FSH peak ratio was >1 in six (66.6%) CPP girls.

CONCLUSIONS

None of the available tests alone allows identification of girls who will progress to precocious puberty. Elevated LH responses to GnRH are common but are not related to progression toward puberty. The combined measurement of basal LH and longitudinal diameter of the uterus represents a reliable screening approach to identify subjects who should undergo GnRH testing.

[Does childhood obesity affect sexual development?]

The process of pubertal development is only partly understood and is influenced by many different factors. During the twentieth century there was a general trend toward earlier pubertal development. Fat mass is thought to be a major inducer of puberty. Owing to the rising epidemic of childhood obesity, the relationship between body composition in children and the rate and timing of puberty needs to be investigated. Some studies suggest that central obesity is associated with an earlier onset of pubertal development. Rapid weight gain in early life is linked to advanced puberty in both sexes. A clear correlation exists between increasing body mass index (BMI) and earlier pubertal development in girls. In boys the data are controversial: The majority of studies propose that there is an earlier puberty and voice break in obese boys, but some studies show the opposite. There are several factors and mechanisms that seem to link obesity and puberty, for example, leptin, adipocytokines, and gut peptides. Important players include genetic variation and environmental factors (e.g., endocrine-disrupting chemicals). This article presents the latest studies and evidence on this topic, underlining the inconsistencies in the data and, therefore, the need for further research in this area.

Study protocol: the Childhood to Adolescence Transition Study (CATS)

Background

Puberty is a multifaceted developmental process that begins in late-childhood with a cascade of endocrine changes that ultimately lead to sexual maturation and reproductive capability. The transition through puberty is marked by an increased risk for the onset of a range of health problems, particularly those related to the control of behaviour and emotion. Early onset puberty is associated with a greater risk of cancers of the reproductive tract and cardiovascular disease. Previous studies have had methodological limitations and have tended to view puberty as a unitary process, with little distinction between adrenarche, gonadarche and linear growth. The Childhood to Adolescence Transition Study (CATS) aims to prospectively examine associations between the timing and stage of the different hormonally-mediated changes, as well as the onset and course of common health and behavioural problems that emerge in the transition from childhood to adolescence. The initial focus of CATS is on adrenarche, the first hormonal process in the pubertal cascade, which begins for most children at around 8 years of age.

Methods/Design

CATS is a longitudinal population-based cohort study. All Grade 3 students (8–9 years of age) from a stratified cluster sample of schools in Melbourne, Australia were invited to take part. In total, 1239 students and a parent/guardian were recruited to participate in the study. Measures are repeated annually and comprise student, parent and teacher questionnaires, and student anthropometric measurements. A saliva sample was collected from students at baseline and will be repeated at later waves, with the primary purpose of measuring hormonal indices of adrenarche and gonadarche.

Discussion

CATS is uniquely placed to capture biological and phenotypic indices of the pubertal process from its earliest manifestations, together with anthropometric measures and assessment of child health and development. The cohort will provide rich detail of the development, lifestyle, external circumstances and health of children during the transition from childhood through to adolescence. Baseline associations between the hormonal measures and measures of mental health and behaviour will initially be examined cross-sectionally, and then in later waves longitudinally. CATS will make a unique contribution to the understanding of adrenarche and puberty in children’s health and development.

Arg-Phe-amide-related peptides influence gonadotropin-releasing hormone neurons

The hypothalamic Arg-Phe-amide-related peptides, gonadotropin-inhibitory hormone and orthologous mammalian peptides of Arg-Phe-amide, may be important regulators of the hypothalamus-pituitary-gonadal reproductive axis. These peptides may modulate the effects of kisspeptins because they are presently recognized as the most potent activators of the hypothalamus-pituitary-gonadal axis. However, their effects on gonadotropin-releasing hormone neurons have not been investigated. In the current study, the GT1-7 cell line-expressing gonadotropin-releasing hormone was used as a model to explore the effects of Arg-Pheamide-related peptides on kisspeptin activation. Intracellular calcium concentration was quantified using the calcium-sensitive dye, fura-2 acetoxymethyl ester. Gonadotropin-releasing hormone released into the medium was detected via enzyme-linked immunosorbent assay. Results showed that 100 nmol/L kisspeptin-10 significantly increased gonadotropin-releasing hormone levels (at 120 minutes of exposure) and intracellular calcium concentrations. Co-treatment of kisspeptin with 1 μmol/L gonadotropin-inhibitory hormone or 1 μmol/L Arg-Phe-amide-related peptide-1 significantly attenuated levels of kisspeptin-induced gonadotropin-releasing hormone but did not affect kisspeptin-induced elevations of intracellular calcium concentration. Overall, the results suggest that gonadotropin-inhibitory hormone and Arg-Phe-amide-related peptide-1 may have inhibitory effects on kisspeptin-activated gonadotropin-releasing hormone neurons independent of the calcium signaling pathway.

Surging Hormones: Brain-Behavior Interactions During Puberty

In this paper we discuss the surging hormones of puberty and their influences on adolescent behavior. We describe why these issues represent an interesting and important area of investigation, emphasizing their contributions to a specific set of developmental processes at the heart of the transition from childhood to adolescence. We briefly review the neuroendocrine underpinnings of human puberty. Our review focuses on evidence for behavioral (and neurobehavioral) effects of gonadal hormones, and emphasizes the social and affective dimensions of these hormonal effects. More broadly, we consider how these hormonal events contribute to brain-behavior interactions that can bias early adolescent trajectories in both positive and negative directions, and in ways that may begin as small influences, but can spiral into large-scale effects over time. These influences also appear to play an important role in functional and structural brain development during adolescence. Finally we offer some thoughts on directions for future research in these areas.

Longitudinal study of hormonal and physical development in young twins

CONTEXT AND OBJECTIVE

Information on the correlation of normative reproductive hormone levels with physical development (Tanner stages) during puberty and on the influences of genes and environment on variation in these hormones and Tanner stages is limited.

DESIGN, SETTING, AND PARTICIPANTS

One hundred twelve healthy 9-year-old twin pairs (n = 224) took part in a longitudinal study, of which 89 pairs participated again at age 12 years (n = 178).

MAIN OUTCOME MEASURES

Morning urinary LH, FSH, estradiol, and salivary testosterone levels, determined by competitive immunoassays, were measured. Tanner stages were determined through physical examination.

RESULTS

Over the 3-year interval, all hormone levels showed a 2- to 9-fold increase. LH and FSH at age 9 years predicted sex-specific Tanner stages at age 12 years in both boys and girls. Most of the associations between hormone levels at age 9 years and physical development at 12 years were explained by genetic influences. FSH in 9-year-old boys correlated with all hormone levels and Tanner stages at age 12 years. Moderate to high heritability estimates were found for hormone levels at both ages and in both sexes. In girls a shift from environmental (age 9 years) to genetic influences (age 12 years) was found for estradiol and pubic hair development, and for breast development a shift in the opposite direction was seen.

CONCLUSIONS

During development LH and FSH (and testosterone in boys) levels predict secondary sexual characteristics in boys and girls 3 years later. These correlations are largely due to genes that are involved in both early pubertal hormone levels and subsequent physical development.

Vaginal bleeding in a 4-month-old preterm girl: extreme minipuberty mimicking central precocious puberty

We present a 4-month-old girl who showed vaginal bleeding and breast development. She was born preterm at 25 weeks and 4 days of gestation. Luteinizing hormone and follicle-stimulating hormone levels were extremely elevated. Magnetic resonance imaging showed a lesion of unknown nature in the pituitary gland, most likely a Rathke's cleft cyst. Because central precocious puberty (CPP) was suspected, a gonadotropin-releasing hormone analogue was started. At the age of 18 months, the treatment was stopped. Thereafter, no signs of puberty developed. The pituitary lesion remained unchanged. Therefore, the initial diagnosis of CPP was incorrect, and instead, an extreme minipuberty had occurred. If treatment for idiopathic CPP in girls younger than 2 years is started, we recommend the treatment be stopped after a certain period, for reevaluation of the diagnosis of CPP.

Brain SCALE: brain structure and cognition: an adolescent longitudinal twin study into the genetic etiology of individual differences

From childhood into adolescence, the child's brain undergoes considerable changes in both structure and function. Twin studies are of great value to explore to what extent genetic and environmental factors explain individual differences in brain development and cognition. In The Netherlands, we initiated a longitudinal study in which twins, their siblings and their parents are assessed at three year intervals. The participants were recruited from The Netherlands Twin Register (NTR) and at baseline consisted of 112 families, with 9-year-old twins and an older sibling. Three years later, 89 families returned for follow-up assessment. Data collection included psychometric IQ tests, a comprehensive neuropsychological testing protocol, and parental and self-ratings of behavioral and emotional problems. Physical maturation was measured through assessment of Tanner stages. Hormonal levels (cortisol, luteinizing hormone, follicle-stimulating hormone, testosterone, and estrogens) were assessed in urine and saliva. Brain scans were acquired using 1.5 Tesla Magnetic Resonance Imaging (MRI), which provided volumetric measures and measures of cortical thickness. Buccal swabs were collected for DNA isolation for future candidate gene and genome-wide analysis studies. This article gives an overview of the study and the main findings. Participants will return for a third assessment when the twins are around 16 years old. Longitudinal twin-sibling studies that map brain development and cognitive function at well-defined ages aid in the understanding of genetic influences on normative brain development.

Neural systems supporting cognitive-affective interactions in adolescence: the role of puberty and implications for affective disorders

Evidence from longitudinal studies suggests that adolescence may represent a period of vulnerability that, in the context of adverse events, could contribute to developmental trajectories toward behavioral and emotional health problems, including affective disorders. Adolescence is also a sensitive period for the development of neural systems supporting cognitive-affective processes, which have been implicated in the pathophysiology of affective disorders such as anxiety and mood disorders. In particular, the onset of puberty brings about a cascade of physical, hormonal, psychological, and social changes that contribute in complex ways to the development of these systems. This article provides a brief overview of neuroimaging research pertaining to the development of cognitive-affective processes in adolescence. It also includes a brief review of evidence from animal and human neuroimaging studies suggesting that sex steroids influence the connectivity between prefrontal cortical and subcortical limbic regions in ways that contribute to increased reactivity to emotionally salient stimuli. We integrate these findings in the context of a developmental affective neuroscience framework suggesting that the impact of rising levels of sex steroids during puberty on fronto-limbic connectivity may be even greater in the context of protracted development of prefrontal cortical regions in adolescence. We conclude by discussing the implications of these findings for future research aimed at identifying neurodevelopmental markers of risk for future onset of affective disorders.

Effects of obesity on human sexual development

Puberty is a period of physical and psychological maturation, with long-term effects on health. During the 20(th) century, a secular trend towards earlier puberty occurred in association with improvements in nutrition. The worldwide pandemic of childhood obesity has renewed interest in the relationship between body composition in childhood and the timing and tempo of puberty. Limited evidence suggests that earlier puberty is associated with a tendency towards central fat deposition; therefore, pubertal status needs to be carefully considered in the categorization of childhood and adolescent overweight and obesity. In the other direction, rapid early weight gain is associated with advanced puberty in both sexes, and a clear association exists between increasing BMI and earlier pubertal development in girls. Evidence in boys is less clear, with the majority of studies showing obesity to be associated with earlier puberty and voice break, although a subgroup of boys with obesity exhibits late puberty, perhaps as a variation of constitutional delay in growth and puberty. The possible mechanisms linking adiposity with pubertal timing are numerous, but leptin, adipocytokines and gut peptides are central players. Other possible mediators include genetic variation and environmental factors such as endocrine disrupting chemicals. This Review presents current evidence on this topic, highlighting inconsistencies and opportunities for future research.

A potential mechanism for the sexual dimorphism in the onset of puberty and incidence of idiopathic central precocious puberty in children: sex-specific kisspeptin as an integrator of puberty signals

The major determinants of the variability in pubertal maturation are reported to be genetic and inherited. Nonetheless, nutritional status contributes significantly to this variability. Malnutrition delays puberty whereas obesity has been associated to a rise in Idiopathic Central Precocious Puberty (ICPP) in girls. However, epidemiology data indicate that contribution of obesity to early puberty varies significantly among ethnic groups, and that obesity-independent inheritable genetic factors are the strongest predictors of early puberty in any ethnic group. In fact, two human mutations with confirmed association to ICPP have been identified in children with no history of obesity. These mutations are in kisspeptin and kisspeptin receptor, a ligand/receptor pair with a major role on the onset of puberty and female cyclicity after puberty. Progressive increases in kisspeptin expression in hypothalamic nuclei known to regulate reproductive function has been associated to the onset of puberty, and hypothalamic expression of kisspeptin is reported to be sexually dimorphic in many species, which include humans. The hypothalamus of females is programmed to express significantly higher levels of kisspeptin than their male counterparts. Interestingly, incidence of ICPP and delayed puberty in children is markedly sexually dimorphic, such that ICPP is at least 10-fold more frequent in females, whereas prevalence of delayed puberty is about 5-fold higher in males. These observations are consistent with a possible involvement of sexually dimorphic kisspeptin signaling in the sexual dimorphism of normal puberty and of pubertal disorders in children of all ethnicities. This review discusses the likelihood of such associations, as well as a potential role of kisspeptin as the converging target of environmental, metabolic, and hormonal signals, which would be integrated in order to optimize reproductive function.

White matter development in adolescence: the influence of puberty and implications for affective disorders

There have been rapid advances in understanding a broad range of changes in brain structure and function during adolescence, and a growing interest in identifying which of these neurodevelopmental changes are directly linked with pubertal maturation—at least in part because of their potential to provide insights into the numerous emotional and behavioral health problems that emerge during this developmental period. This review focuses on what is known about the influence of puberty on white matter development in adolescence.We focus on white matter because of its role in providing the structural architectural organization of the brain and as a structural correlate of communication within complex neural systems. We begin with a review of studies that report sex differences or sex by age interactions in white matter development as these findings can provide, although indirectly,information relevant to puberty-related changes. Studies are also critically reviewed based on methodological procedures used to assess pubertal maturation and relations with white matter changes. Findings are discussed in light of their implications for the development of neural systems underlying the regulation of emotion and behavior and how alterations in the development of these systems may mediate risk for affective disorders in vulnerable adolescents.

Socio-environmental factors associated with pubertal development in female adolescents: the role of prepubertal tobacco and alcohol use

PURPOSE

Alcohol administered to laboratory animals has been shown to suppress puberty-related hormones and delay puberty by interfering with ovarian development and function. The effects of early substance use on human pubertal development are relatively unexplored.

METHODS

This cross-sectional study of 3,106 female adolescents, aged 11-21 years, evaluated the association between prepubertal alcohol and tobacco use and the onset of puberty. Ages at initial breast development, body hair growth, and menarche were self-reported. Prepubertal alcohol and tobacco use were defined as the age at first use before the age of pubertal development and accompanied by regular use. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazard models. Logistic regression was used to estimate the association between substance use and delayed puberty, defined as lack of breast development by the age of 13 years.

RESULTS

Unadjusted models indicated prepubertal tobacco use was associated with a longer time required for breast development (HR = 0.74; 95% CI, 0.65-0.85) and body hair growth (HR = 0.81; 95% CI, 0.71-0.93). Prepubertal alcohol use was associated with late breast development (HR = 0.71; 95% CI, 0.57-0.88). The direction of the observed associations remained consistent after adjusting for covariates, but the magnitude of effects were attenuated and the upper bound of the 95% CIs exceeded the null value. Girls who used alcohol before puberty had four times the odds of having delayed puberty (OR = 3.99; 95% CI, 1.94-8.21) as compared with nonusers.

CONCLUSION

The results of this study suggest that the endocrine-disrupting effects of alcohol and tobacco use may alter the timing of pubertal development. These cross-sectional findings warrant further investigation.

Sex steroids and brain structure in pubertal boys and girls: a mini-review of neuroimaging studies

Puberty is an important period during development hallmarked by increases in sex steroid levels. Human neuroimaging studies have consistently reported that in typically developing pubertal children, cortical and subcortical gray matter is decreasing, whereas white matter increases well into adulthood. From animal studies it has become clear that sex steroids are capable of influencing brain organization, both during the prenatal period as well as during other periods characterized by massive sex steroid changes such as puberty. Here we review structural neuroimaging studies and show that the changes in sex steroids availability during puberty and adolescence might trigger a period of structural reorganization of grey and white matter in the developing human brain. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.

An association study between the genetic polymorphisms within GnRHI, LHβ and FSHβ genes and central precocious puberty in Chinese girls

OBJECTIVES

Gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are three hypothalamic-pituitary-gonadal axis expressing hormones. They play critical roles in the onset of puberty. Here we report the relationship between the three hormones and Central Precocious Puberty (CPP) in Chinese Han girls.

METHODS

We analyzed the single nucleotide polymorphisms (SNPs) of 5'-flanking regions of these genes by DNA sequencing in 27 CPP samples. Then the SNPs sites were genotyped by ligase detection reaction in a total of 283 Chinese Han CPP cases and 284 matched controls. Distributions of the polymorphisms and haplotypes were calculated for statistical evaluation.

RESULTS

Nine SNPs (One in GnRHI gene: -2003 C/T; Five in LHβ gene: -1456 C/G, -1424 C/G, -238 G/A, -164 G/A and -34 T/A; Three in FSHβ gene: -1825 T/C, -261 G/T and -132 T/A.) were found. A quantitative genetic association study was made. -1825 T/C in FSHβ gene was related with CPP with a weak effect (P=0.025). A haplotype in the 5'-flanking region of LHβ gene was significantly associated with CPP in Chinese Han girls (P=8.25×10(-09)). However, analysis software showed that none of SNP was found in the regulating control element of these genes.

CONCLUSIONS

Our finding implies that the polymorphisms in the 5'-flanking regions of FSHβ gene and LHβ gene probably were related to the puberty onset time of these girls. Further studies on the polymorphisms are needed for the exact mechanism.

Effect of acupuncture on pubertal development of rats and rabbits at different developmental stages

Physiological and endocrine studies on sexual development in animals and effects of acupuncture on sexual development are limited. Therefore, we investigated the effect of electro-acupuncture (EA) on the arcuate nucleus (Arc) and release of gonadotropin-releasing hormone (GnRH) in animals at different developmental stages. In Experiment 1, EA stimulation (30 Hz) was performed for 30 min per day in EA group of rabbits for 48 days, while the control group (mature rabbits) was not given EA. Arc discharges in those two groups were measured after the 48-day treatment. Arc discharge was also measured in the pre-pubertal group (as control) without EA treatment. Then, all three groups were treated with transient EA for 30 min and Arc discharges were determined again. In Experiment 2, EA (3 Hz) at the same acupoints or non-acupoints as that in the rabbits was performed for 20 min per day in different developmental group of Sprague-Dawley rats for 10 days. GnRH mRNA expression in the hypothalamus of rats was determined using RT-PCR and real-time PCR. The serum sexual hormone, sperm count, and body weight was measured. The results showed that the Arc discharge (P<0.01), testosterone (T) (P<0.01) and sperm count (P<0.01) in male rabbits were reduced by repeated EA. However, the body weight of rabbits was not changed after EA compared to the control in Experiment 1. In Experiment 2, GnRH mRNA expression in rats of the early pubertal group (EPG) and adult group (AG) were significantly depressed after repeated EA at acupoints (P<0.01). The sexual hormones were negatively influenced by repeated EA during puberty. Sperm count was reduced significantly after repeated EA at time of puberty (P<0.01). Repeated EA did not influence body weight of rats (P>0.01) and structures of the gonadial tissues during development. The results suggested that repeated EA is a good option that can be considered for regulating the function of the hypothalamus-pituitary-gonad (HPG) axis during puberty.

Pharmacogenomic and Structural Analysis of Constitutive G Protein–Coupled Receptor Activity

G protein-coupled receptors (GPCRs) respond to a chemically diverse plethora of signal transduction molecules. The notion that GPCRs also signal without an external chemical trigger, i.e., in a constitutive or spontaneous manner, resulted in a paradigm shift in the field of GPCR pharmacology. The discovery of constitutive GPCR activity and the fact that GPCR binding and signaling can be strongly affected by a single point mutation drew attention to the evolving area of GPCR pharmacogenomics. For a variety of GPCRs, point mutations have been convincingly linked to human disease. Mutations within conserved motifs, known to be involved in GPCR activation, might explain the properties of some naturally occurring, constitutively active GPCR variants linked to disease. In this review, we provide a brief historical introduction to the concept of constitutive receptor activity and the pharmacogenomic and structural aspects of constitutive receptor activity.

Serum androgen bioactivity in adolescence: a longitudinal study of boys with constitutional delay of puberty

We have examined the relationship between serum androgen bioactivity, as measured with a recombinant cell bioassay, and progression of puberty in 14 boys with constitutional delay of puberty. Six boys were followed up without treatment (control group), and eight boys received low-dose (1 mg/kg) testosterone enanthate im for 0-6 months together with an aromatase inhibitor, letrozole, 2.5 mg orally once a day for 0-12 months (treatment group). In the control group, serum androgen bioactivity increased during the course of puberty (P < 0.001). During 0-12 months of the study, the boys in the treatment group had higher androgen bioactivity levels (P < 0.05) and faster rate of pubic hair growth than the control boys (P < 0.05). Overall, the average serum androgen bioactivity during 12 months of follow-up correlated strongly with the concomitant changes in Tanner genital (r(S) = 0.89; n = 13; P < 0.005) and pubic hair stages (r(S) = 0.79; n = 13; P < 0.01). In conclusion, our results suggest that circulating androgen bioactivity mediates the tempo of pubertal maturation and that the combination of testosterone and letrozole given to boys with constitutional delay of puberty accelerates puberty.