Pre-pubertal exposure with phthalates and bisphenol A and pubertal development

OBJECTIVE

Epidemiological studies indicate associations between childhood exposure with phthalates and bisphenol A (BPA) and the pubertal development. We examined associations between the pre-pubertal phthalate and BPA body burden and the longitudinally assessed sexual maturation of eight- to thirteen-year-old children.

METHODS

We started with eight- to ten-year-old children in the baseline study and quantified phthalate metabolites and BPA in 472 urine samples (250 boys; 222 girls; mean age: 8.8 years). Associations between the pubertal development, assessed in three annual follow-up studies by Puberty Development scale questionnaires (PD scales), and the chemical exposure from the baseline visit were longitudinally analyzed with generalized estimation equations.

RESULTS

The number of children with both chemical measures and PD scores (calculated from the PD scales) was 408. In the third follow-up, 49% of the girls and 18% of the boys had reached mid-puberty. For girls, we observed a delayed pubertal development with the di-hexyl-ethyl phthalate (DEHP) metabolites (β: -0.16 to -0.23; p ≤ 0.05 or p ≤ 0.1), mono-n-butyl phthalate (β: -0.15; 95% CI: -0.31; 0.01), mono-benzyl phthalate (β: -0.11; 95% CI: -0,24; -0,01), and mono-ethyl phthalate (MEP) (β: -0.15; 95% CI: -0.28; -0.01). In addition, significant non-linear associations of the DEHP metabolites and BPA with the PD scores were found, when their quadratic effects were included in the GEE models. In boys, no consistent relationships between the PD scores and the chemicals were detected except of an accelerated development with the ∑DEHP metabolites (β: 0.16; 95% CI: -0.02; -0.34).

CONCLUSION

We found indications that pre-pubertal exposures with phthalates and BPA were associated with pubertal timing in children, particularly in girls. For boys, associations were inconsistent, and not necessarily in line with the known anti-androgenicity of some phthalates during prenatal exposure.

Developmental differences in reward sensitivity and sensation seeking in adolescence: Testing sex-specific associations with gonadal hormones and pubertal development

Sensation seeking has been found to increase, on average, from childhood to adolescence. Developmental scientists have hypothesized that this change could be driven by the rise of gonadal hormones at puberty, which affect reward-related processing in the brain. In a large, age-heterogeneous, population-based sample of adolescents and young adults (N = 810; ages 13-20 years), we tested for sex-specific associations between age, self-reported pubertal development, gonadal hormones (estradiol and testosterone) as measured in saliva, reward sensitivity as measured by a multivariate battery of in-laboratory tasks (including the Iowa gambling task, balloon analogue risk task, and stoplight task), and self-reported sensation seeking. Reward sensitivity was more strongly associated with sensation seeking in males than females. For both males and females, reward sensitivity was unrelated to age but was higher among those who reported more advanced pubertal development. There were significant sex differences in the effects of self-reported pubertal development on sensation seeking, with a positive association evident in males but a negative association in females. Moreover, gonadal hormones also showed diverging associations with sensation seeking-positive with testosterone but negative with estradiol. Overall, the results indicate that sensation seeking among adolescents and young adults depends on a complex constellation of developmental influences that operate via sex-specific mechanisms. (PsycINFO Database Record

Hormonal correlates of development and natal dispersal in wild female owl monkeys (Aotus azarae) of Argentina

Pair-living and socially monogamous primates typically do not reproduce before dispersing. It is currently unclear whether this reproductive suppression is due to endocrine or behavioral mechanisms. Cooperatively breeding taxa, like callitrichids, may forego reproduction in natal groups because they reap inclusive fitness benefits and/or they are avoiding inbreeding. However, neither of these benefits of delayed reproduction appear to adequately explain the lack of reproduction prior to leaving the natal group in pair-living monogamous species. In this study, we determined whether wild Azara's owl monkeys (Aotus azarae) in the Argentinean Chaco establish reproductive maturity prior to dispersing. We utilized 635 fecal extracts to characterize reproductive hormone profiles of 11 wild juvenile and subadult females using enzyme immunoassays. Subadult females showed hormone profiles indicative of ovulatory cycling and had mean PdG and E1G concentrations approximately five times higher than juveniles. Contrary to expectations from the inbreeding avoidance hypothesis, female owl monkeys do not delay puberty, but rather commence ovarian cycling while residing in their natal group. Still, subadults appear to have a period during which they experience irregular, non-conceptive cycles prior to reproducing. Commencing these irregular cycles in the natal group may allow them to develop a state of suspended readiness, which could be essential to securing a mate, while avoiding costs of ranging solitarily. Our results indicate that reproductive suppression in female owl monkeys is not due to endocrine suppression. We suggest that adults likely use behavioral mechanisms to prevent subadults from reproducing with unrelated adult males in their natal group.

Endocrine disrupting effects of waterborne fluoxetine exposure on the reproductive axis of female goldfish, Carassius auratus

Evidence suggests that pharmaceuticals and personal care products reach urban watersheds, bioconcentrate in fish, and potentially disrupt physiological homeostasis. These impairments often affect hormone functions. Selective serotonin reuptake inhibitors (SRRIs) are increasingly studied with regards to their endocrine disrupting effects on teleost physiological processes, including reproduction. To examine whether FLX effects on the endocrine regulation of reproductive physiology in goldfish are sex-specific, we exposed sexually recrudescent female goldfish to two waterborne concentrations of FLX (0.54μg/L and 54μg/L) using an experimental design previously used for sexually mature male goldfish. To evaluate possible endocrine disrupting effects, we quantified the gonadosomatic index, circulating hormone concentrations (luteinizing hormone, LH; growth hormone, GH; 17-β estradiol, E₂; and testosterone, T), and the expression of isotocin and vasotocin in the telencephalon, gonadotropin subunits and GH in the pituitary, and gonadotropin receptors, GH receptors, and aromatase in the ovary. Female goldfish exposed to 0.54μg/L FLX exhibited a significant decrease in circulating E₂, and conversely, a significant increase in circulating LH and ovarian aromatase mRNA levels, suggesting disruption of E₂-mediated feedback on LH release. These results, when compared with those previously observed in males, reveal that waterborne exposure to environmentally relevant levels of FLX sex-specifically disrupts the reproductive endocrine axis in goldfish, characterized by a decrease in E₂ in females, and conversely, estrogen-like effects in males. These data emphasize the importance of studying the effect of endocrine disrupting chemicals on both sexes.

Markers of pubertal timing and leisure-time physical activity from ages 36 to 68 years: findings from a British birth cohort

OBJECTIVES

We aimed to examine associations between markers of pubertal timing and leisure-time physical activity (LTPA) from ages 36 to 68 years in men and women from the Medical Research Council National Survey of Health and Development.

STUDY DESIGN

Pubertal timing was ascertained by physicians at age 14-15 years. Boys were grouped, based on their secondary sexual characteristics, as prepubescent, in early-stage puberty, advanced stage puberty or fully mature at age 14-15 years. Girls were grouped as reaching menarche ≤11, 12, 13 or ≥14 years. LTPA was reported at ages 36, 43, 53, 60-64 and 68 years and classified as active or inactive at each age. Associations were examined using standard and mixed-effects logistic regression models.

RESULTS

Of 5362 singleton births recruited, 1499 men and 1409 women had at least one measure of LTPA and data on pubertal timing and selected covariates. When compared with men that were fully mature at age 14-15 years, those that were in advanced stage and early-stage puberty, but not the prepubescent stage, had lower likelihood of LTPA at younger but not older adult ages (p=0.06 for pubertal status-by-age at LTPA interaction in mixed-effects model). For example, fully adjusted ORs of LTPA (vs no LTPA) at ages 36 and 68 years, respectively, for advanced puberty versus fully mature were 0.69 (95% CIs 0.50 to 0.96) and 1.03 (0.72 to 1.47). Age at menarche was not associated with LTPA at any age (p_interaction with age at LTPA=0.9). For example, OR (from mixed-effects model) of LTPA between 36 and 68 years was 1.23 (0.93, 1.63) for menarche at 13 vs ≤11 years.

CONCLUSIONS

In a nationally representative study, there was little evidence to suggest that pubertal timing was an important correlate of LTPA between ages 36 and 68 years. Maturity-related variations in adolescents' LTPA may be transitory and lose importance over time.

Transdiagnostic psychiatric disorder risk associated with early age of menarche: A latent modeling approach

BACKGROUND

Earlier age of pubertal maturation in females is associated with increased risk for mental health problems in adolescence, compared with on-time or later maturation. However, most investigations of pubertal timing and mental health consider risk for individual disorders and fail to account for comorbidity. A latent-modeling approach using a large, nationally representative sample could better explain the transdiagnostic nature of the consequences of early-onset puberty.

METHODS

Data on age of menarche and mental disorders were drawn from a population-representative sample of adolescents (n=4925), ages 13-17. Confirmatory factor analysis was used to fit four latent disorder categories: distress, eating, and externalizing, and fear disorders. Timing of menarche included those with earlier (age≤10, age 11) and later age of onset (age 13, 14+), relative to those with average timing of menarche (age 12). Associations between timing of menarche and latent disorders were estimated in a structural equation model (SEM), adjusted for age, income, race, parent marital status, BMI, and childhood adversity.

RESULTS

The measurement model evidenced acceptable fit (CFI=0.91; RMSEA=0.02). Onset of menarche before age 11 was significantly associated with distress disorders (coefficient=0.096; p<0.0001), fear disorders (coefficient=0.09; p<0.0001), and externalizing disorders (coefficient=0.039; p=0.049) as compared to on-time or late menarche. No residual associations of early menarche with individual disorders over and above the latent disorders were observed.

CONCLUSION

The latent modeling approach illuminated meaningful transdiagnostic psychiatric associations with early timing of menarche. Biological processes initiated at puberty can influence cognitive and affective processes as well as social relationships for adolescents. Under developmentally normative conditions, these changes may be adaptive. However, for those out of sync with their peers, researchers and clinicians should recognize the potential for these processes to influence liability to a broad array of psychopathological consequences in adolescence.

Prepubertal Development of Gonadotropin-Releasing Hormone Neuron Activity Is Altered by Sex, Age, and Prenatal Androgen Exposure

Gonadotropin-releasing hormone (GnRH) neurons regulate reproduction though pulsatile hormone release. Disruption of GnRH release as measured via luteinizing hormone (LH) pulses occurs in polycystic ovary syndrome (PCOS), and in young hyperandrogenemic girls. In adult prenatally androgenized (PNA) mice, which exhibit many aspects of PCOS, increased LH is associated with increased GnRH neuron action potential firing. How GnRH neuron activity develops over the prepubertal period and whether this is altered by sex or prenatal androgen treatment are unknown. We hypothesized GnRH neurons are active before puberty and that this activity is sexually differentiated and altered by PNA. Dams were injected with dihydrotestosterone (DHT) on days 16 to 18 post copulation to generate PNA mice. Action potential firing of GFP-identified GnRH neurons in brain slices from 1-, 2-, 3-, and 4-week-old and adult mice was monitored. GnRH neurons were active at all ages tested. In control females, activity increased with age through 3 weeks, then decreased to adult levels. In contrast, activity did not change in PNA females and was reduced at 3 weeks. Activity was higher in control females than males from 2 to 3 weeks. PNA did not affect GnRH neuron firing rate in males at any age. Short-term action potential patterns were also affected by age and PNA treatment. GnRH neurons are thus typically more active during the prepubertal period than adulthood, and PNA reduces prepubertal activity in females. Prepubertal activity may play a role in establishing sexually differentiated neuronal networks upstream of GnRH neurons; androgen-induced changes during this time may contribute to the adult PNA, and possibly PCOS, phenotype.

Psychosocial and Psychological Vulnerability in Adolescents with Gender Dysphoria: A "Proof of Principle" Study

For adolescents with gender dysphoria, it has become common to be offered hormonal treatment to either delay or suppress pubertal development and/or to masculinize or feminize the body. At the same time, it has been our clinical impression that the psychological vulnerability of at least some of these youth has been overlooked. Fifty consecutive referrals of adolescents with a DSM-IV-TR diagnosis of gender identity disorder (GID) constituted the sample. Information obtained at intake was coded for the presence or absence of 15 psychosocial and psychological vulnerability factors. The mean number of psychosocial/psychological vulnerability factors coded as present was 5.56 (range, 0-13). Over half of the sample had six or more of the vulnerability factors. The number of factors coded as present was significantly correlated with behavioral and emotional problems on the Youth Self-Report Form and the Child Behavior Checklist, but not with demographic variables or IQ. The findings supported the clinical impression that a large percentage of adolescents referred for gender dysphoria have a substantial co-occurring history of psychosocial and psychological vulnerability, thus supporting a "proof of principle" for the importance of a comprehensive psychologic/psychiatric assessment that goes beyond an evaluation of gender dysphoria per se.

Puberty arises with testicular alterations and defective AMH expression in rams prenatally exposed to testosterone

The male gonadal tissue can be a sensitive target to the reprogramming effects of testosterone (T) during prenatal development. We have demonstrated that male lambs born to dams receiving T during pregnancy-a model system to the polycystic ovary syndrome (PCOS)-show a decreased number of germ cells early in life, and when adult, a reduced amount of sperm and ejaculate volume. These findings are a key to put attention to the male offspring of women bearing PCOS, as they are exposed to increased levels of androgen during pregnancy which can reprogram their reproductive outcome. A possible origin of these defects can be a disruption in the expression of the anti-Müllerian hormone (AMH), due to its critical role in gonadal function at many postnatal stages. Therefore, we addressed the impact of prenatal T excess on the expression of AMH and factors related to its expression like AP2, SOX9, FSHR, and AR in the testicular tissue through real-time PCR during the peripubertal age. We also analyzed the testicular morphology and quantified the number of Sertoli cells and germ cells to evaluate any further defect in the testicle. Experiments were performed in rams at 24 wk of age, hence, prior puberty. The experimental animals (T-males) consisted of rams born to mothers receiving 30 mg testosterone twice a wk from Day 30 to 90 of pregnancy and then increased to 40 mg until Day 120 of pregnancy. The control males (C-males) were born to mothers receiving the vehicle of the hormone. We found a significant increase in the expression of the mRNA of AMH and SOX9, but not of the AP2, FHSR nor AR, in the T-males. Moreover, T-males showed a dramatic decrease in the number of germ cells, together with a decrease in the weight of their testicles. The findings of the present study show that before puberty, T-males are manifesting clear signs of disruption in the gonadal functions probably due to an alteration in the expression pattern of the AMH gene. The precise way by which T reprograms the expression of AMH gene remains to be established.

Kisspeptin and Neurokinin B Signaling Network Underlies the Pubertal Increase in GnRH Release in Female Rhesus Monkeys

Loss-of-function or inactivating mutations in the genes coding for kisspeptin and its receptor (KISS1R) or neurokinin B (NKB) and the NKB receptor (NK3R) in humans result in a delay in or the absence of puberty. However, precise mechanisms of kisspeptin and NKB signaling in the regulation of the pubertal increase in gonadotropin-releasing hormone (GnRH) release in primates are unknown. In this study, we conducted a series of experiments infusing agonists and antagonists of kisspeptin and NKB into the stalk-median eminence, where GnRH, kisspeptin, and NKB neuroterminal fibers are concentrated, and measuring GnRH release in prepubertal and pubertal female rhesus monkeys. Results indicate that (1) similar to those previously reported for GnRH stimulation by the KISS1R agonist (i.e., human kisspeptin-10), the NK3R agonist senktide stimulated GnRH release in a dose-responsive manner in both prepubertal and pubertal monkeys; (2) the senktide-induced GnRH release was blocked in the presence of the KISS1R antagonist peptide 234 in pubertal but not prepubertal monkeys; and (3) the kisspeptin-induced GnRH release was blocked in the presence of the NK3R antagonist SB222200 in the pubertal but not prepubertal monkeys. These results are interpreted to mean that although, in prepubertal female monkeys, kisspeptin and NKB signaling to GnRH release is independent, in pubertal female monkeys, a reciprocal signaling mechanism between kisspeptin and NKB neurons is established. We speculate that this cooperative mechanism by the kisspeptin and NKB network underlies the pubertal increase in GnRH release in female monkeys.

Inhibiting Production of New Brain Cells during Puberty or Adulthood Blunts the Hormonally Induced Surge of Luteinizing Hormone in Female Rats

New cells are added during both puberty and adulthood to hypothalamic regions that govern reproduction, homeostasis, and social behaviors, yet the functions of these late-born cells remain elusive. Here, we pharmacologically inhibited cell proliferation in ventricular zones during puberty or in adulthood and determined subsequent effects on the hormone-induced surge of luteinizing hormone (LH) in female rats. Initial neuroanatomical analyses focused on verifying incorporation, activation, and pharmacological inhibition of pubertally or adult born cells in the anteroventral periventricular nucleus (AVPV) of the hypothalamus because of the essential role of the AVPV in triggering the preovulatory LH surge in females. We first showed that approximately half of the pubertally born AVPV cells are activated by estradiol plus progesterone (P) treatment, as demonstrated by Fos expression, and that approximately 10% of pubertally born AVPV cells express estrogen receptor alpha (ERα). Next, we found that mitotic inhibition through intracerebroventricular (ICV) administration of cytosine β-D-arabinofuranoside (AraC), whether during puberty or in adulthood, decreased the number of new cells added to the AVPV and the suprachiasmatic nucleus (SCN), and also blunted and delayed the hormone-induced LH surge. These studies do not prove, but are highly suggestive, that ongoing postnatal addition of new cells in periventricular brain regions, including the AVPV and SCN, may be important to the integrity of female reproduction.

Sertoli Cell Number Defines and Predicts Germ and Leydig Cell Population Sizes in the Adult Mouse Testis

Sertoli cells regulate differentiation and development of the testis and are essential for maintaining adult testis function. To model the effects of dysregulating Sertoli cell number during development or aging, we have used acute diphtheria toxin-mediated cell ablation to reduce Sertoli cell population size. Results show that the size of the Sertoli cell population that forms during development determines the number of germ cells and Leydig cells that will be present in the adult testis. Similarly, the number of germ cells and Leydig cells that can be maintained in the adult depends directly on the size of the adult Sertoli cell population. Finally, we have used linear modeling to generate predictive models of testis cell composition during development and in the adult based on the size of the Sertoli cell population. This study shows that at all ages the size of the Sertoli cell population is predictive of resulting testicular cell composition. A reduction in Sertoli cell number/proliferation at any age will therefore lead to a proportional decrease in germ cell and Leydig cell numbers, with likely consequential effects on fertility and health.

Within-person changes in salivary testosterone and physical characteristics of puberty predict boys' daily affect

Recent investigations highlighted the role of within-person pubertal changes for adolescents' behavior. Yet, little is known about effects on adolescents' daily affect, particularly regarding the hormonal changes underlying physical changes during puberty. In a study with 148 boys aged 10 to 20years, we tested whether within-person physical and hormonal changes over eight months predicted everyday affect fluctuations, measured with experience sampling. As expected, greater within-person changes in testosterone (but not in dehydroepiandrosterone) were associated with higher affect fluctuations in daily life. Additionally, greater physical changes predicted higher affect fluctuations for individuals in the beginning of puberty. The findings demonstrate the relevance of physical and hormonal changes in boys' affective (in)stability.

Role of amygdala kisspeptin in pubertal timing in female rats

To investigate the mechanism by which maternal obesity disrupts reproductive function in offspring, we examined Kiss1 expression in the hypothalamic arcuate (ARC) and anteroventral periventricular (AVPV) nuclei, and posterodorsal medial amygdala (MePD) of pre-pubertal and young adult offspring. Sprague-Dawley rats were fed either a standard or energy-dense diet for six weeks prior to mating and throughout pregnancy and lactation. Male and female offspring were weaned onto normal diet on postnatal day (pnd) 21. Brains were collected on pnd 30 or 100 for qRT-PCR to determine Kiss1 mRNA levels. Maternal obesity increased Kiss1 mRNA expression in the MePD of pre-pubertal male and female offspring, whereas Kiss1 expression was not affected in the ARC or AVPV at this age. Maternal obesity reduced Kiss1 expression in all three brain regions of 3 month old female offspring, but only in MePD of males. The role of MePD kisspeptin on puberty, estrous cyclicity and preovulatory LH surges was assessed directly in a separate group of post-weanling and young adult female rats exposed to a normal diet throughout their life course. Bilateral intra-MePD cannulae connected to osmotic mini-pumps for delivery of kisspeptin receptor antagonist (Peptide 234 for 14 days) were chronically implanted on pnd 21 or 100. Antagonism of MePD kisspeptin delayed puberty onset, disrupted estrous cyclicity and reduced the incidence of LH surges. These data show that the MePD plays a key role in pubertal timing and ovulation and that maternal obesity may act via amygdala kisspeptin signaling to influence reproductive function in the offspring.

Global differential gene expression in the pituitary gland and the ovaries of pre- and postpubertal Brahman heifers

To understand genes, pathways, and networks related to puberty, we characterized the transcriptome of two tissues: the pituitary gland and ovaries. Samples were harvested from pre- and postpubertal Brahman heifers (same age group). Brahman heifers () are older at puberty compared with , a productivity issue. With RNA sequencing, we identified differentially expressed (DEx) genes and important transcription factors (TF) and predicted coexpression networks. The number of DEx genes detected in the pituitary gland was 284 ( < 0.05), and was the most DEx gene (fold change = 4.12, = 0.01). The gene promotes bone mineralization through transforming growth factor-β (TGFβ) signaling. Further studies of the link between bone mineralization and puberty could target . In ovaries, 3,871 genes were DEx ( < 0.05). Four highly DEx genes were noteworthy for their function: (a γ-aminobutyric acid [GABA] transporter), (), and () and its receptor . These genes had higher ovarian expression in postpubertal heifers. The GABA and its receptors and transporters were expressed in the ovaries of many mammals, suggesting a role for this pathway beyond the brain. The pathway has been known to influence the timing of puberty in rats, via modulation of GnRH. The effects of at the hypothalamus, pituitary gland, and ovaries have been documented. and its receptors are known factors in the release of GnRH, similar to and GABA, although their roles in ovarian tissue are less clear. Pathways previously related to puberty such as TGFβ signaling ( = 6.71 × 10), Wnt signaling ( = 4.1 × 10), and peroxisome proliferator-activated receptor (PPAR) signaling ( = 4.84 × 10) were enriched in our data set. Seven genes were identified as key TF in both tissues: , , , , , , and a novel gene. An ovarian subnetwork created with TF and significant ovarian DEx genes revealed five zinc fingers as regulators: , , , , and . Recent work of hypothalamic gene expression also pointed to zinc fingers as TF for bovine puberty. Although some zinc fingers may be ubiquitously expressed, the identification of DEx genes in common across tissues points to key regulators of puberty. The hypothalamus and pituitary gland had eight DEx genes in common. The hypothalamus and ovaries had 89 DEx genes in common. The pituitary gland and ovaries had 48 DEx genes in common. Our study confirmed the complexity of puberty and suggested further investigation on genes that code zinc fingers.

Extensive BMI Gain in Puberty is Associated with Lower Increments in Bone Mineral Density in Estonian Boys with Overweight and Obesity: A 3-Year Longitudinal Study

The aim of this 3-year prospective study was to examine changes in bone mineral characteristics during pubertal maturation in boys with different BMI values at the beginning of puberty and with different BMI increments during puberty. 26 boys with overweight and obesity (OWB) and 29 normal weight boys (NWB) were studied yearly for 3 years from the age of 11 years to measure the changes in different bone mineral characteristics. The OWB group was further divided into two subgroups according to extensive or non-extensive BMI increment during 3-year period. OWB had higher (P < 0.01) baseline total body (TB) bone mineral density (BMD), TB bone mineral content (BMC), TB BMC for height, lumbar spine (LS) BMD, and LS BMC compared to NWB. Throughout the study period, OWB gained more TB BMD (P = 0.0001), TB BMC (P = 0.0048), TB BMC for height (P = 0.0124), LS BMD (P = 0.0029), and LS BMC (P = 0.0022) compared to NWB. Also during the study period, TB BMD (P = 0.0065), TB BMC (P = 0.0141), TB BMC for height (P = 0.0199), LS BMD (P = 0.0066), LS apparent volumetric BMD (BMAD) (P = 0.0075), and LS BMC (P = 0.017) increased significantly less in those OWB whose BMI increased more extensively. Extensive BMI gain is associated with lower increments in bone mineral characteristics in boys with overweight and obesity. Unfavorable increment in total body fat mass and percentage during pubertal years could be one reason for that.

Comparison of celioscopy and histological examinations to assess male gonadal health and functionality in adults and immature wild raptors

Celioscopy is routinely used in birds for sex determination and diagnostic purposes. Aim of this work was to validate celioscopy for the assessment of male gonads functionality in wild raptors, comparing the results of direct observation with morphometrical and histological characteristics. The work was done at the 'Centro Animali Non Convenzionali' of the University of Turin, Italy, on 31 endoscopically evaluated raptors that died or were euthanized. Through celioscopic observation, the birds were classified in adults or immatures and maturity categories were defined according to the adrenal-gonad size ratio and to the degree of blood filling of testicular vessels. The gonads were removed immediately after death/euthanasia and measured. Albuginea tunic thickness, diameter of seminiferous tubules, number of meiosis figures, tubular development degree, tubular degeneration degree and germinal cells production degree were evaluated. Testicular size tended to increase from immature to adult birds and from 'out of' to 'in' breeding season; albuginea tunic thickness tended to be higher out of the reproductive season while diameter of the seminiferous tubules, germinative epithelium thickness and number of meiosis figures were higher in the breeding season. In season adults generally showed higher values in tubular development and germinal cells production, and lower degrees of tubular cells degeneration and fibrosis. From the interpretation of all the morphometrical and histological aspects, a general reproductive degree of activity was given to the birds and compared with celioscopic results. A perfect concordance was found in 23 out of 31 cases and a good concordance in six ones; histology could describe obviously better sub-clinical conditions undetectable at direct observation. These preliminary results suggest that celioscopy could be a useful tool to assess male gonads functionality in wild raptors, with the future goal to select the better potential semen donors.

An acute social defeat stressor in early puberty increases susceptibility to social defeat in adulthood

Syrian hamsters readily display territorial aggression. If they lose even a single agonistic encounter, however, hamsters show striking reductions in aggressive behavior and increases in submissive behavior, a distinct behavioral change that we have previously termed conditioned defeat. This acute social defeat stressor is primarily psychological and is effective in both males and females. Therefore, we maintain that this procedure presents an ideal model for studying behavioral and physiological responses to social stress. Here, we demonstrate that social avoidance following social defeat is a particularly useful dependent measure because of its sensitivity and stability between sexes and across the estrous cycle. In addition, we demonstrate that peripubertal hamsters exposed to a single, 15min social defeat exhibit significantly more social avoidance 24h later when compared with no-defeat controls. Later, defeated and non-defeated hamsters display similar agonistic behavior in adulthood indicating that the peripubertal defeat does not alter adult territorial aggression. After experiencing an additional social defeat in adulthood, however, the hamsters that experienced the pubertal defeat respond to the adult defeat with increased social avoidance when compared with hamsters that were defeated only in adulthood and with no-defeat controls. These data are the first to show that a single social defeat in puberty increases susceptibility to later social defeat in both males and females.

TRIENNIAL REPRODUCTION SYMPOSIUM: Developmental programming of fertility

The 2015 Triennial Reproduction Symposium focused on developmental programming of fertility. The topics covered during the morning session included the role of the placenta in programming of fetal growth and development, effects of feeding system and level of feeding during pregnancy on the annual production cycle and lifetime productivity of heifer offspring, effects of litter size and level of socialization postnatally on reproductive performance of pigs, effects of postnatal dietary intake on maturation of the hypothalamic-pituitary-gonadal axis and onset of puberty in heifers, effects of housing systems on growth performance and reproductive efficiency of gilts, and effects of energy balance on sexual differentiation in rodent models. The morning session concluded with presentation of the American Society of Animal Science L. E. Casida Award for Excellence in Graduate Education to Dr. Michael Smith from the University of Missouri, Columbia, who shared his philosophy of graduate education. The afternoon session included talks on the role of epigenetic modifications in developmental programming and transgenerational inheritance of reproductive dysfunction, effects of endocrine disrupting compounds on fetal development and long-term physiology of the individual, and potential consequences of real-life exposure to environmental contaminants on reproductive health. The symposium concluded with a summary talk and the posing of 2 questions to the audience. From an evolutionary standpoint, programming and epigenetic events must be adaptive; when do they become maladaptive? If there are so many environmental factors that induce developmental programming, are we doomed, and if not, what is or are the solution or solutions?

Becoming a sexual being: The 'elephant in the room' of adolescent brain development

The onset of adolescence is a time of profound changes in motivation, cognition, behavior, and social relationships. Existing neurodevelopmental models have integrated our current understanding of adolescent brain development; however, there has been surprisingly little focus on the importance of adolescence as a sensitive period for romantic and sexual development. As young people enter adolescence, one of their primary tasks is to gain knowledge and experience that will allow them to take on the social roles of adults, including engaging in romantic and sexual relationships. By reviewing the relevant human and animal neurodevelopmental literature, this paper highlights how we should move beyond thinking of puberty as simply a set of somatic changes that are critical for physical reproductive maturation. Rather, puberty also involves a set of neurobiological changes that are critical for the social, emotional, and cognitive maturation necessary for reproductive success. The primary goal of this paper is to broaden the research base and dialogue about adolescent romantic and sexual development, in hopes of advancing understanding of sex and romance as important developmental dimensions of health and well-being in adolescence.

Testicular growth and development in puberty

PURPOSE OF REVIEW

To describe pubertal testicular growth in humans, changes in testicular cell populations that result in testicular growth, and the role of testosterone and gonadotrophins follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in testicular growth. When human data were not available, studies in nonhuman primates and/or rodents were used as surrogates.

RECENT FINDINGS

Testicular growth in puberty follows a sigmoidal growth curve, with a large variation in timing of testicular growth and adult testicular volume. Testicular growth early in puberty is due to increase in Sertoli cell number and length of seminiferous tubules, whereas the largest and fastest growth results from the increase in the diameter of the seminiferous tubules first due to spermatogonial proliferation and then due to the expansion of meiotic and haploid germ cells. FSH stimulates Sertoli cell and spermatogonial proliferation, whereas LH/testosterone is mandatory to complete spermatogenesis. However, FSH and LH/testosterone work in synergy and are both needed for normal spermatogenesis.

SUMMARY

Testicular growth during puberty is rapid, and mostly due to germ cell expansion and growth in seminiferous tubule diameter triggered by androgens. Pre-treatment with FSH before the induction of puberty may improve the treatment of hypogonadotropic hypogonadism, but remains to be proven.

TAC1 Gene Products Regulate Pituitary Hormone Secretion and Gene Expression in Prepubertal Grass Carp Pituitary Cells

Tachykinin-1 (TAC1) is known to have diverse functions in mammals, but similar information is scarce in fish species. Using grass carp as a model, the pituitary actions, receptor specificity and postreceptor signaling of TAC1 gene products, namely substance P (SP) and neurokinin A (NKA), were examined. TAC1 encoding SP and NKA as well as tachykinin receptors NK1R and NK2R were cloned in the carp pituitary. The newly cloned receptors were shown to be functional with properties similar to mammalian counterparts. In carp pituitary cells, SP and NKA could trigger luteinizing hormone (LH), prolactin (PRL), and somatolactin α (SLα) secretion, with parallel rises in PRL and SLα transcripts. Short-term SP treatment (3 hours) induced LH release, whereas prolonged induction (24 hours) could attenuate LHβ messenger RNA (mRNA) expression. At pituitary cell level, LH, PRL, and SLα regulation by TAC1 gene products were mediated by NK1R, NK2R, and NK3R, respectively. Apparently, SP- and NKA-induced LH and SLα secretion and transcript expression were mediated by adenylyl cyclase/cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA), phospholiphase C (PLC)/inositol 1,4,5-triphosphate/protein kinase C (PKC), and Ca2+/calmodulin (CaM)/CaM-dependent protein kinase-II pathways. The signal transduction for PRL responses was similar, except for the absence of a PKC component. Regarding SP inhibition of LHβ mRNA expression, the cAMP/PKA- and PLC/PKC-dependent (but not Ca2+/CaM-dependent) cascades were involved. These results, as a whole, suggest that TAC1 gene products play a role in LH, PRL, and SLα regulation via overlapping postreceptor signaling coupled to different subtypes of tachykinin receptor expressed in the carp pituitary.

Clinical and laboratory parameters predicting a requirement for the reevaluation of growth hormone status during growth hormone treatment: Retesting early in the course of GH treatment

OBJECTIVE

We aimed to define the predictive criteria, in the form of specific clinical, hormonal and radiological parameters, for children with growth hormone deficiency (GHD) who may benefit from the reevaluation of GH status early in the course of growth hormone (GH) treatment.

DESIGN AND METHODS

Two hundred sixty-five children with growth hormone deficiency were retested by GH stimulation at the end of the first year of GH treatment. The initial clinical and laboratory characteristics of those with a normal (GH≥10ng/ml) response and those with a subnormal (GH<10ng/ml) response were compared to predict a normal GH status during reassessment.

RESULTS

Sixty-nine patients (40.6%) out of the 170 patients with isolated growth hormone deficiency (IGHD) had a peak GH of ≥10ng/ml during the retest. None of the patients with multiple pituitary hormone deficiency (MPHD) had a peak GH of ≥10ng/ml. Puberty and sex steroid priming in peripubertal cases increased the probability of a normal GH response. Only one patient with IGHD who had an ectopic posterior pituitary without stalk interruption on MRI analysis showed a normal GH response during the retest. Patients with a peak GH between 5 and 10ng/ml, an age at diagnosis of ≥9years or a height gain below 0.61 SDS during the first year of treatment had an increased probability of having a normal GH response at the retest.

CONCLUSION

Early reassessment of GH status during GH treatment is unnecessary in patients who have MPHD with at least 3 hormone deficiencies. Retesting at the end of the first year of therapy is recommended for patients with IGHD who have a height gain of <0.61 SDS in the first year of treatment, especially those with a normal or 'hypoplastic' pituitary on imaging. Priming can increase the likelihood of a normal response in patients in the pubertal age group who do not show overt signs of pubertal development.

Effects of Adrenal Androgen Levels on Bone Age Advancement in Prepubertal Children: Using the Ewha Birth and Growth Cohort Study

Bone age (BA) advancement in prepubertal children may be associated with earlier onset of puberty and obesity. This study aimed to define the effects of adrenal androgen levels on the advancement of BA in prepubertal children, independent of obesity. During July and August 2011, we examined BA in 200 prepubertal children aged 7-9 years who were part of the Ewha Birth & Growth Cohort Study. BA was assessed by the Greulich-Pyle method. An index of BA advancement was calculated as the ratio of BA to chronological age (CA) (BA/CA), and this ratio was classified into 3 tertiles. We analyzed the relationship between BA advancement and anthropometric characteristics and adrenal hormone levels. The number of overweight children increased from the first group to the third group (P(Trend) = 0.03). The levels of adrenal androgens showed a significant positive correlation with the tertile groups after adjusting for age and sex (testosterone: r = 0.26, P < 0.001; dehydroepiandrosterone: r = 0.21, P < 0.001; androstenedione: r = 0.20, P < 0.001). Further, after controlling for body mass index (BMI), sex, and age, the BA/CA was found to be positively correlated with androstenedione (β = 0.04, R² = 3.7%) and testosterone levels (β = 0.05, R² = 4.7%). Based on our results, it is suggested that adrenal androgen levels are associated with BA advancement independent of BMI.

The Role of Context in Psychosocial Stress among Adolescents with Autism Spectrum Disorder: Piloting a Semi-structured, Videogame-based Paradigm

BACKGROUND

Autism Spectrum Disorder (ASD) is characterised by altered social patterns, often associated with increased stress. While puberty is associated with increased stress, there is limited research on stress response to social interaction in adolescents with ASD. The study investigated stress response to semi-structured, videogame-based interaction in adolescents with and without ASD, and the impact of puberty.

METHOD

Twelve adolescents with ASD and 12 typically developing (TD) peers participated in a semi-structured, videogame-based social interaction. Stress was measured via salivary cortisol.

RESULTS

There were no significant between-group differences in cortisol. Pubertal development was correlated with cortisol in ASD (r = -0.901, p < 0.0001), but not TD (r = 0.022, p = 0.949).

CONCLUSIONS

Findings contribute to a fuller picture of the developmental trajectories of physiological stress in ASD, including the importance of context, structure, and puberty. The current investigation underscores the necessity of incorporating varied social contexts when assessing stress and social interaction.

Endocrinology of human female sexuality, mating, and reproductive behavior

Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes.

Gender and gonadal maturity stage identification of captive Chinese sturgeon, Acipenser sinensis, using ultrasound imagery and sex steroids

Long lifespan and late maturation make it difficult to establish gamete maturity and breeding age of captive endangered Chinese sturgeon, Acipenser sinensis. This greatly handicaps timely breeding and future conservation stocking efforts. We used ultrasound imagery and sex steroids to determine the gender and gonadal maturity stage of captive Chinese sturgeon (age, 10-17years old). The echogenicity of the reproductive organs and the respective morphology of the gonads were described and two quantitative parameters p_o (proportion of the ovary to the entire reproductive organs) and d (thickness of the reproductive organs) were measured to characterize sex and maturity stage of Chinese sturgeon. Females were accordingly placed fish into several categories: F_II (F_II^-, F_II, F_II⁺), F_III (F_III, F_III⁺) and F_IV (F_IV, F_IV⁺) and F_VI and males as M_II, M_III, M_IV, M_V and M_VI. The accuracy of gender and maturity stage determination provided by ultrasonographic methods was 72.7% for F_II^- ovary (n=11) and 76.2% for M_II testis (n=42). Accuracy of sex and maturity determination using only serum sex steroid of testosterone (T) and estradiol-17β (E₂) was low (58-73%, depending on maturity stage). However, when the two methods were used together, accuracy increased sharply, especially for immature (II stage) females. In summary, of 151 Chinese sturgeon, whose sex and maturity stage were independently confirmed, 88.1% (n=133), 62.9% (n=95), and 96.7% (n=146) were successfully sexed and staged using ultrasound, sex steroids, or both methods, respectively. The results provide reliable non-invasive techniques for determining sex and gonadal maturation of captive Chinese sturgeon. These methods can track individual gonad characteristics over multi-year reproductive cycles, which will assist captive broodstock management, artificial reproduction, and future conservation stocking.

Endocrinology, energetics, and human life history: A synthetic model

Human life histories are shaped by the allocation of metabolic energy to competing physiological domains. A model framework of the pathways of energy allocation is described and hormonal regulators of allocation along the pathways of the framework are discussed in the light of evidence from field studies of the endocrinology of human energetics. The framework is then used to generate simple models of two important life history transitions in humans, puberty and the postpartum return to full fecundity in females. The results of the models correspond very closely to observations made in the field.

Sex discordance in asthma and wheeze prevalence in two longitudinal cohorts

Sex discordance in asthma prevalence has been previously reported, with higher prevalence in males before puberty, and in females after puberty; the adolescent "switch". However, cross-sectional studies have suggested a narrowing of this discordance in recent decades. We used a combination of cross-sectional and longitudinal modelling to examine sex differences in asthma, wheeze and longitudinal wheezing phenotypes in two UK birth cohorts, the Avon Longitudinal Study of Parents and Children (ALSPAC; born 1991-92 with data from age 0-18 years) and the Millennium Cohort Study (MCS; born 2000-02 with data from age 3-10 years). We derived measures of asthma and wheeze from questionnaires completed by mothers and cohort children. Previously-derived ALSPAC wheezing phenotype models were applied to MCS. Males had a higher prevalence of asthma at 10.7 years in ALSPAC (OR 1.45 95%CI: 1.26, 1.66 n = 7778 for current asthma) and MCS (OR 1.42 95%CI: 1.29, 1.56 n = 6726 for asthma ever) compared to females, decreasing in ALSPAC after puberty (OR 0.94 95%CI: 0.79, 1.11 n = 5023 for current asthma at 16.5 years). In longitudinal models using restricted cubic splines, males had a clear excess for asthma in the last 12 months and wheeze in the last 12 months up until 16.5 years of age in ALSPAC. Males had an increased risk of all derived longitudinal wheezing phenotypes in MCS when compared to never wheeze and no evidence of being at lower risk of late wheeze when compared to early wheeze. By comparing data in two large, contemporary cohorts we have shown the persistence of sex discordance in childhood asthma, with no evidence that the sex discordance is narrowing in recent cohorts.

Transcriptome analyses identify five transcription factors differentially expressed in the hypothalamus of post- versus prepubertal Brahman heifers

Puberty onset is a developmental process influenced by genetic determinants, environment, and nutrition. Mutations and regulatory gene networks constitute the molecular basis for the genetic determinants of puberty onset. The emerging knowledge of these genetic determinants presents opportunities for innovation in the breeding of early pubertal cattle. This paper presents new data on hypothalamic gene expression related to puberty in (Brahman) in age- and weight-matched heifers. Six postpubertal heifers were compared with 6 prepubertal heifers using whole-genome RNA sequencing methodology for quantification of global gene expression in the hypothalamus. Five transcription factors (TF) with potential regulatory roles in the hypothalamus were identified in this experiment: , , , , and . These TF genes were significantly differentially expressed in the hypothalamus of postpubertal versus prepubertal heifers and were also identified as significant according to the applied regulatory impact factor metric ( < 0.05). Two of these 5 TF, and , were zinc fingers, belonging to a gene family previously reported to have a central regulatory role in mammalian puberty. The gene belongs to the family of homologues of Drosophila sine oculis () genes implicated in transcriptional regulation of gonadotrope gene expression. Tumor-related genes such as and are known to affect basic cellular processes that are relevant in both cancer and developmental processes. Mutations in were associated with puberty in humans. Mutations in these TF, together with other genetic determinants previously discovered, could be used in genomic selection to predict the genetic merit of cattle (i.e., the likelihood of the offspring presenting earlier than average puberty for Brahman). Knowledge of key mutations involved in genetic traits is an advantage for genomic prediction because it can increase its accuracy.

Age-dependent features of CYP3A, CYP2C, and CYP2E1 functioning at metabolic syndrome

BACKGROUND

Complex investigations of cytochrome P450 (CYP) isoforms with metabolic syndrome (MS) development are limited, and specific features of adolescent's metabolisms are generally disregarded. The aim of present study was a comparative estimation of MS-mediated changes in CYP3A, CYP2C, and CYP2E1 mRNA expression and enzymatic activities, as well as antioxidant system parameters of adult and pubertal rats.

METHODS

Wistar albino male rats of two age categories [young animals of 21 days age (50-70 g) and adults (160-180 g)] were divided into four groups (eight animals in each group): (1) control 1 (intact young rats), (2) control 2 (intact adult rats), (3) MS3 (young rats with MS), and (4) MS4 (adult rats with MS). The MS was induced by full replacement of drinking water by 20% fructose solution (200 g/L). After 60 days of MS modeling, the investigation of rat liver CYP3A, CYP2C, and CYP2E1 mRNA expressions, their enzyme-marker activities, as well as the antioxidant system parameters was conducted.

RESULTS

Levels of liver CYP2E1 mRNA expression increased with MS: 40% (adults) and 80% (pubertal rats). Pubertal rats had also increased CYP3A2 mRNA expression (30%) and decreased CYP2C mRNA expression (30%). Changes in CYP2E1 and CYP2C enzymatic activities were consistent with the changes of corresponding gene expressions at both age-groups with MS. Simultaneously, liver reduced glutathione contents, and glutathione transferase and reductase activities were decreased in pubertal animals.

CONCLUSIONS

CYP isoform expression rates and glutathione system were greatly violated with MS. The greater changes were observed in pubertal rats with MS.

Tobacco smoke exposure induces irreversible alteration of testicular function in prepubertal rats

BACKGROUND

Smoking is a serious public health problem and an important risk factor of many diseases. The present study evaluated whether or not the influence of prolonged tobacco smoke (TS) exposure on spermatic indices and reproductive hormones would be reversible in young and adult rats.

METHODS

Prepubertal and adult rats were grouped into five (I, II, III, IV, and V) separately (n=5/group) and exposed to TS at target concentrations of 0, 0.5, 1.0, 0.5, and 1.0 mg nicotine/day, respectively for 30 days using the whole body exposure inhalation method. Groups I, II, and III were sacrificed 24 h after TS exposure, while groups IV and V were allowed to recover for 30 days before they were sacrificed.

RESULTS

Sperm count and motility were significantly (p<0.05) reduced in exposed prepubertal and adult rats. Additionally, sperm morphology was unaltered, testosterone was reduced, while luteinizing hormone (LH) and follicle stimulating hormone (FSH) were elevated compared to the non-TS exposed control group. The reductions in sperm count and motility were reversed only in adult recovery rats. LH and FSH elevations were reversed in all recovery animals, but testosterone concentrations remained lower than control. Furthermore, malondialdehyde levels in testes of exposed rats were significantly increased. This was reversed only in adult recovery rats that received 0.5 mg nicotine. Testicular levels of catalase, reduced glutathione, and superoxide dismutase were unaltered, except in prepubertal rats wherein catalase was decreased in both treated and recovery groups.

CONCLUSIONS

The TS exposure alters sperm characteristics reversibly in adult, but irreversibly in prepubertal rats, which is attributable to elevation of oxidative stress.

Long-term effects of adolescent stress on neophobic behaviors in zebra finches are modulated by social context when in adulthood

Experiencing stress during adolescence can increase neophobic behaviors in adulthood, but most tests have been conducted in the absence of conspecifics. Conspecifics can modulate responses to stressors, for example by acting as 'social buffers' to attenuate the aversive appraisal of stressors. Here, we investigate the long-term effects of adolescent stress on the behavioral responses to novel stimuli (a mild stressor) across social contexts in an affiliative passerine bird, the zebra finch. During early (days 40-60) or late (days 65-85) adolescence the birds (n=66) were dosed with either saline or the hormone corticosterone (CORT). CORT was given in order to mimic a physiological stress response and saline was given as a control. In adulthood, the birds' behavioral responses to a novel environment were recorded in both the presence and absence of conspecifics. An acute CORT response was also quantified in adolescence and adulthood. Our findings show clear evidence of social context mediating any long-term effects of adolescent stress. In the presence of familiar conspecifics no treatment effects were detected. Individually, birds dosed with CORT in early adolescence were slower to enter a novel environment, spent more time perching in the same novel environment, and, if female, engaged in more risk assessment. Birds dosed in late adolescence were unaffected. No treatment effects were detected on CORT, but adolescents had a higher CORT concentration than adults. Our results are the first to suggest that familiar conspecifics in adulthood can buffer the long-term effects of stress that occurred during early adolescence.

Immune-endocrine interactions in marsupials and monotremes

Interactions between the immune and endocrine systems are not well studied in marsupials and monotremes. One exception to this is the phenomenon of semelparity, which is well covered in the literature as this is an unusual reproductive strategy amongst mammals and is only observed in some dasyurid and didelphid marsupials. Thymus involution provides a direct link between the endocrine and immune systems and warrants further study in marsupials and monotremes. The thymus is a primary immune tissue which is essential for overall immune function. Whilst the organ is large in juvenile animals, it begins to involute around puberty due to the suppressive effects of sex steroids. Thymus involution has a significant effect on the immune system, as it signals the onset of immune aging and decline in function. The output of naïve T lymphocytes by the thymus decreases, increasing susceptibility of aged individuals to infection and cancers. Understanding the links between the immune and endocrine system in marsupials and monotremes may shed light on diseases such as devil facial tumour disease (DFTD) which threatens the future of the Tasmanian devil. We hypothesise that changes in sex hormones around puberty may drive changes in the immune system, such as thymus involution, which may make devils more susceptible to DFTD as they age. In addition, the Schwann cell origin of DFTD may enable tumours to respond to sex hormones, as occurs in similar cancers in humans.

Temporal and spatial comparisons of the reproductive biology of northern Gulf of Mexico (USA) red snapper (Lutjanus campechanus) collected a decade apart

In studies done a decade apart, we provide evidence of a recent shift toward a slower progression to sexual maturity as well as reduced egg production, especially among young, small female red snapper, in the Gulf of Mexico (Gulf). Slower maturation rates (among fish ≤6 years old), lower GSI values and decreased spawning frequency were observed, and were especially pronounced in the northwestern Gulf. Furthermore, an Index of Reproductive Importance showed that young fish (ages 2-7) are contributing far less to the spawning stock in recent years, while older fish (>8 years) are contributing more, when compared to fish from the same age groups sampled in the previous decade. Coincident with these changes in reproductive output, fishing pressure has steadily declined gulf-wide, and spawning stock biomass and spawning potential ratio have increased. Thus, it is possible that the age structure of the red snapper stock is becoming less truncated, or that reproductive effort observed is due to the temporary influence of recent strong year classes produced in 2004 and 2006 as they begin to reach full reproductive potential. If the latter is true, careful documentation of the stock's reproductive dynamics during a time of population growth provides new understanding at the meta-population spatial and decadal temporal scales. In contrast, if the former is true, a truncated age structure due to overharvest can limit the productivity of the Gulf red snapper stock. In addition, we have learned that red snapper females in the northwestern Gulf collected on natural reefs and banks have much higher reproductive output than those on artificial reefs in the form of standing and toppled oil and gas platforms, thus making the need to know the relative abundance of females found on these disparate habitats an important next step toward better-understanding factors impacting the reproductive dynamics of this species.

Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico

Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the "rapprochement" skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp's ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends.

Reproduction of the duck catfish Ageneiosus ucayalensis in a ria river system

A total of 1006 duck catfish Ageneiosus ucayalensis were collected from a ria river system of eastern Amazonia, of which 733 were females and 273 males, a sex ratio 2·69:1. Condition factors of males were higher than those of females and size at first sexual maturity (L₅₀ ) was 12·8 cm for females and 11·8 cm for males. The relative frequency of mature specimens and gonad condition indices indicate that the breeding season is short and coincides with the rainy season.

[Basic biological parameters for Pseudocurimata lineopunctata (Characiformes, Curimatidae) conservation in the Anchicayá River of the Cauca Valley, Colombia]

Pseudocurimata lineopunctata represents an important nutritional source for local human communities in Colombia and Ecuador. Although the yearly catch of this fish is low (590 kg/year), there are no restrictions on minimum size, and this species is categorized as vulnerable with moderate extinction risk by the Regional Autonomous Corporation of the Cauca Valley (Colombia). To support conservation programs, biological data of the target species are required. Therefore, the aims of this study were to describe the sex ratio, distribution, size to weight ratio, macroscopic stages of reproductive maturity, fecundity, and size at first sexual maturity for P. lineopunctata. For this, fish samples were captured with nets over nine months (February-October) in 2007. The total length (Lt) of the captured fish ranged between 10.7 and 16.5 cm, with total weight (Pt) between 25.0 and 67.5 g. Females represented 52.6 % of the sample group while males represented 47.4 %, and differences in sex ratio were observed in relation to fish size. For all sampled months, the fish captured showed an advanced maturity state. Based on analyses of the gonadosomatic index (IGS), gonadic index (IG), and Fulton’s condition factor (K), and two spawning peaks were determined, one in June-July, and the other in September-October. The size at first sexual maturity was 9.2 cm for females and 10.1 cm for males. Absolute fecundity was estimated as 3 598 oocytes/g♀. It is necessary to carry out additional investigations on the reproduction of this species, to support future repopulation programs.

Seven cases with Williams-Beuren syndrome: endocrine evaluation and long-term follow-up

BACKGROUND

Endocrine evaluation and long-term follow-up of seven (six male) patients with Williams-Beuren syndrome (WBS) are given.

METHOD

Data were obtained from patients' medical records. All patients underwent hormonal analyses and four of them underwent oral glucose tolerance test (OGTT).

RESULTS

They all had mild hypercalcemia. Three of them had overt hypothyroidism while subclinical hypothyroidism was detected in three patients. Four patients had thyroid hypoplasia and one had thyroid agenesis. Growth hormone deficiency (GHD) was determined in one patient. Impaired glucose tolerance (IGT) was found in three adolescents. All adolescents had early-onset puberty. The follow-up duration was 5.7±2.1 years. The mean growth velocity (GV) was 12.9±7.2 cm and 7.6±2 cm at the end of the first and second years of therapy, respectively. All patients had neurodevelopment retardation and were continuing to special education.

CONCLUSIONS

Thyroid hypoplasia is common and agenesis can be seen in patients with WBS; therefore, thyroid hormones should be measured in the newborn period and annually. GHD should be kept in mind in patients with decreased GV. IGT might be detected in patients with WBS even in adolescence.

Does the degree of endocrine dyscrasia post-reproduction dictate post-reproductive lifespan? Lessons from semelparous and iteroparous species

Post-reproductive lifespan varies greatly among species; human post-reproductive lifespan comprises ~30-50% of their total longevity, while semelparous salmon and dasyurid marsupials post-reproductive lifespan comprises <4% of their total longevity. To examine if the magnitude of hypothalamic-pituitary-gonadal (HPG) axis dyscrasia at the time of reproductive senescence determines post-reproductive lifespan, we examined the difference between pre- and post-reproductive (1) circulating sex hormones and (2) the ratio of sex steroids to gonadotropins (e.g., 17β-estradiol/follicle-stimulating hormone (FSH)), an index of the dysregulation of the HPG axis and the level of dyotic (death) signaling post-reproduction. Animals with a shorter post-reproductive lifespan (<4% total longevity) had a more marked decline in circulating sex steroids and corresponding elevation in gonadotropins compared to animals with a longer post-reproductive lifespan (30-60% total longevity). In semelparous female salmon of short post-reproductive lifespan (1%), these divergent changes in circulating hormone concentration post-reproduction equated to a 711-fold decrease in the ratio of 17β-estradiol/FSH between the reproductive and post-reproductive periods. In contrast, the decrease in the ratio of 17β-estradiol/FSH in iteroparous female mammals with long post-reproductive lifespan was significantly less (1.7-34-fold) post-reproduction. Likewise, in male semelparous salmon, the decrease in the ratio of testosterone/FSH (82-fold) was considerably larger than for iteroparous species (1.3-11-fold). These results suggest that (1) organisms with greater reproductive endocrine dyscrasia more rapidly undergo senescence and die, and (2) the contribution post-reproduction by non-gonadal (and perhaps gonadal) tissues to circulating sex hormones dictates post-reproductive tissue health and longevity. In this way, reproduction and longevity are coupled, with the degree of non-gonadal tissue hormone production dictating the rate of somatic tissue demise post-reproduction and the differences in post-reproductive lifespans between species.

Neuropeptide Y expression confers benzo[a]pyrene induced anxiolytic like behavioral response during early adolescence period of male Wistar rats

Environmental neurotoxicant like benzo[a]pyrene (B[a]P) is known to induce neurobehavioral changes. Our previous reports address the adverse effect of B[a]P on the neurobehavioral responses and neuromorphology of sensitive brain regions in adolescent rats. Present study was conducted on male Wistar rat neonates at postnatal day 5 (PND5) to ascertain B[a]P induced anxiolytic like behavioral response could be an outcome of neuropeptide Y (NPY) overexpression in brain. Single intracisternal administration of B[a]P was carried out at PND5 to elucidate the role of NPY on neurobehavioral responses at PND30. The behavioral studies showed anxiolytic like effect of B[a]P in both light and dark box and elevated plus maze tests. Antioxidant assay involving glutathione peroxidase activity was significantly decreased where as lipid peroxidation was significantly augmented in both hippocampus and hypothalamus of B[a]P treated group as compared to naive and control. The neurotransmitter estimation by HPLC-ECD showed significant increase in 5-HT level in both hippocampus and hypothalamus of B[a]P treated group. Significant elevation in NPY expression was observed in both hippocampus and hypothalamus of B[a]P group. Intracellular Ca²⁺ estimation using Fura-2AM by fluorometry showed that B[a]P induced increase in Ca²⁺ influx was associated with augmented NPY expression in brain. As NPY has orexigenic effect, our result revealed that there was a significant increase in body weight at PND30 following B[a]P administration to rat neonates at PND5. These findings suggested that NPY overexpression in brain regions might be associated with anxiolytic like behavioral response and orexigenic effect in rats following single intracisternal B[a]P administration. Future research directing towards understanding the signaling cascades of B[a]P induced biochemical and neuromorphological alteration might address the independent pathway which induce neurodegeneration despite NPY overexpression in brain regions of adolescent rats.

Plasma concentrations of osteocalcin are associated with the timing of pubertal progress in boys

BACKGROUND

Animal models have shown that the skeletal hormone osteocalcin stimulates testicular testosterone synthesis. To assess whether osteocalcin might be a useful marker to detect pubertal development disorders, we examined osteocalcin plasma concentrations in children and adolescents with and without disorders of pubertal development.

METHODS

Osteocalcin concentrations were investigated in a total of 244 patients with endocrine disorders (122 males, mean age: 11.87+3.77 years), including patients with precocious puberty and constitutional delay of puberty.

RESULTS

Osteocalcin concentrations were highest among adolescents with precocious puberty and advanced pubertal development (120.60±45.22 ng/mL), while the concentrations were lowest among patients with constitutional delay of puberty (102.20±37.13 ng/mL). Overall, osteocalcin concentrations were strongly correlated with markers of bone metabolism.

CONCLUSIONS

Although plasma osteocalcin concentrations are associated with pubertal development in boys, it does not appear to be a useful diagnostic marker for altered pubertal development.

Amenorative effects of exogenous gonadotropins on reproductive profiles of replacement gilts with delayed puberty in a farm in Thailand

This study was to investigate the effect of gonadotropins on reproductive profiles of replacement gilts with delayed puberty. Totally, 136 Landrace X Yorkshire crossbred gilts, were categorized into control (n = 58) and treatment (n = 78) groups. Gonadotropins (400 U eCG plus 200 IU hCG) were administered in treatment group only. The results revealed that gilts in treatment group had higher number of gilts with estrus (92.3 vs 25.9%, P < 0.001), shorter onset to estrus (4.7 ± 0.3 vs 9.0 ± 0.8 d, P < 0.001), higher number of dominant follicles (18.0 ± 0.2 vs 13.2 ± 0.3 follicles, P < 0.001), and higher farrowing rate (87.5 vs 53.3%, P = 0.002) than those in control group. In conclusion, gonadotropins containing 400 IU eCG plus 200 IU hCG could improve reproductive profiles in replacement gilts with delayed puberty.

Ultrasonographic predictors of response of European eels (Anguilla anguilla) to hormonal treatment for induction of ovarian development

OBJECTIVE To examine ultrasonographic predictors of ovarian development in European eels (Anguilla anguilla) undergoing hormonal treatment for assisted reproduction. ANIMALS 83 female European eels. PROCEDURES Eels received weekly IM injections of salmon pituitary extract (first injection = week 1). Ultrasonography of the ovaries was performed twice during hormonal treatment (weeks 7 and 11). Eels were identified on the basis of body weight as having an adequate response by weeks 14 to 20 or an inadequate response after injections for 21 weeks. Eels were euthanized at the end of the experiment and classified by use of ovarian histologic examination. Ovarian cross-sectional area and size of eel (ie, length (3) ) were used to classify eels (fast responder, slow responder, or nonresponder) and to calculate an ultrasonographic-derived gonadosomatic index. Gray-level co-occurrence matrices were calculated from ovarian images, and 22 texture features were calculated from these matrices. RESULTS The ultrasonographic-derived gonadosomatic index differed significantly between fast responders and slow responders or nonresponders at both weeks 7 and 11. Principal component analysis revealed a pattern of separation between the groups, and partial least squares discriminant analysis revealed signals in the ovarian texture that discriminated females that responded to treatment from those that did not. CONCLUSIONS AND CLINICAL RELEVANCE Ovarian texture information in addition to morphometric variables can enhance ultrasonographic applications for assisted reproduction of eels and potentially other fish species. This was a novel, nonlethal method for classifying reproductive response of eels and the first objective texture analysis performed on ultrasonographic images of the gonads of fish.

Does puberty mark a transition in sensitive periods for plasticity in the associative neocortex?

Postnatal brain development is studded with sensitive periods during which experience dependent plasticity is enhanced. This enables rapid learning from environmental inputs and reorganization of cortical circuits that matches behavior with environmental contingencies. Significant headway has been achieved in characterizing and understanding sensitive period biology in primary sensory cortices, but relatively little is known about sensitive period biology in associative neocortex. One possible mediator is the onset of puberty, which marks the transition to adolescence, when animals shift their behavior toward gaining independence and exploring their social world. Puberty onset correlates with reduced behavioral plasticity in some domains and enhanced plasticity in others, and therefore may drive the transition from juvenile to adolescent brain function. Pubertal onset is also occurring earlier in developed nations, particularly in unserved populations, and earlier puberty is associated with vulnerability for substance use, depression and anxiety. In the present article we review the evidence that supports a causal role for puberty in developmental changes in the function and neurobiology of the associative neocortex. We also propose a model for how pubertal hormones may regulate sensitive period plasticity in associative neocortex. We conclude that the evidence suggests puberty onset may play a causal role in some aspects of associative neocortical development, but that further research that manipulates puberty and measures gonadal hormones is required. We argue that further work of this kind is urgently needed to determine how earlier puberty may negatively impact human health and learning potential. This article is part of a Special Issue entitled SI: Adolescent plasticity.

Anal-fin ray morphology indicates sexual maturity in Brevimyrus niger (Teleostei, Mormyridae)

This osteological survey of 249 specimens of Brevimyrus niger ranging in size from 44 to 137 mm standard length (L_S ) demonstrated that developmental changes in anal-fin morphology can serve as a predictor of sexual maturity in this species. Anal-fin ray bases begin to expand when fish reach c. 90 mm L_S at which size and above there were roughly equal numbers of individuals observed with expanded and unmodified anal-fin bases, reflecting a 1:1 sex ratio.

Altered corticosterone levels and social play behavior after prolonged maternal separation in adolescent male but not female Wistar rats

Early-life socio-environmental factors are crucial for normal developmental processes; adverse experiences early in life can therefore lead to detrimental effects in several physiological systems. The aim of this study was to examine short-term effects of early adverse experiences in a maternal separation (MS) rodent model. In this study two separation conditions were used: daily 15- (MS15) or 360-min (MS360) separation of the litter from the dam during postnatal day 1-21. In early adolescence, male and female offspring were subjected to a single-isolation procedure with analysis of corticosterone levels prior to and after isolation. In addition, social play behavior was assessed during mid-adolescence. There was a clear difference between male and female offspring in both tests performed. There was no difference in corticosterone levels between the female MS groups, whereas MS360 males showed higher baseline and recovery corticosterone levels than MS15 males. The amount of pinning, a specific social play behavior, was affected by rearing with MS360 males having a higher frequency than MS15 males, while there was no difference between the female MS groups. The observation that males but not females are affected by MS360 has previously been reported for adult animals, and herein we show that this difference is present already in adolescence. Changes in corticosterone levels and social behavior following early-life adversity have been associated with adult behavioral alterations, and our results confirm that these changes emerge already within adolescence.

Normal Pubertal Development in Daughters of Women With PCOS: A Controlled Study

CONTEXT

Daughters of women with polycystic ovary syndrome (PCOS) are thought to be at increased risk for developing stigmata of the syndrome, but the ontogeny during puberty is uncertain.

OBJECTIVE

We phenotyped daughters (n = 76) of mothers with PCOS and daughters (n = 80) from control mothers for reproductive and metabolic parameters characteristic of PCOS.

DESIGN, SETTING, AND PARTICIPANTS

We performed a matched case/control study at Penn State Hershey Medical Center that included non-Hispanic, white girls 4 to 17 years old.

INTERVENTION

We obtained birth history, biometric, ovarian ultrasounds, whole-body dual-energy X-ray absorptiometry scan for body composition, 2-hour glucose challenged salivary insulin levels, and two timed urinary collections (12 hours overnight and 3 hours in the morning) for gonadotropins and sex steroids.

MAIN OUTCOME MEASURES

We measured integrated urinary levels of adrenal (dehydroepiandrosterone sulfate) and ovarian [testosterone (TT)] steroids. Other endpoints included integrated salivary insulin levels and urinary luteinizing hormone levels.

RESULTS

There were no differences in detection rates or mean levels for gonadotropins and sex steroids in timed urinary collections between PCOS daughters and control daughters, nor were there differences in integrated salivary insulin levels. Results showed that 69% of Tanner 4/5 PCOS daughters vs 31% of control daughters had hirsutism defined as a Ferriman-Gallwey score >8 (P = 0.04). There were no differences in body composition as determined by dual-energy X-ray absorptiometry between groups in the three major body contents (i.e., bone, lean body mass, and fat) or in ovarian volume between groups.

CONCLUSIONS

Matched for pubertal stage, PCOS daughters have similar levels of urinary androgens and gonadotropins as well as glucose-challenged salivary insulin levels.

Photoperiod modulates the reproductive axis of European sea bass through regulation of kiss1 and gnrh2 neuronal expression

The onset of puberty is characterized by activation of the brain-pituitary-gonad axis. However, the molecular and endocrine mechanism involved in the process of puberty and the influence of environmental conditions, such as photoperiod signalling, are not well understood in fish. In this study, 1-year-old male European sea bass (Dicentrarchus labrax) were exposed to photoperiod manipulation in combination with size-sorting. Two treatment groups, a puberty accelerating photoperiod (AP) group and a continuous light (LL) group, were studied from August to February. Our results indicate that AP and LL are able to entrain the rhythms of both kiss1 and gnrh2 mRNA levels in the brain, while kiss2 and gnrh1 mRNA expression does not seem to be directly affected by the photoperiod, at least during testicular growth. It is likely that AP and LL photoperiod regimes affected both plasma Fsh and 11-KT profiles, which might explain, respectively, the phase shift and reduction of testes maturation seen under these conditions. We therefore hypothesize that the unbalanced production of this androgen regulated by circulating Fsh might be limiting the stimulation of germ cell proliferation in European sea bass males. In summary, our study establishes that photoperiod modulates the expression of kiss1 and gnrh2 in the forebrain-midbrain, which may be involved in the translation of the light stimulus to activate the reproductive axis.

Indicators of Biological Maturation and Secular Changes in Biological Maturation

Commonly used indicators of biological maturation are discussed, including sexual, skeletal, morphological, and dental maturity, and the hypothalamus–pituitary–end organ axes that regulate the growth and maturation processes. Interrelationships among indicators and the tempo, timing, and sequence of maturational events are also considered. Environmental factors that influence the level of maturity at a given point in time and the process of maturation are also discussed: undernutrition, obesity, ethnic/racial background, social class, familial characteristics, climate, and altitude. Recommendations for the design of studies of maturational events are made, and an overview of secular changes before and after 1970 is provided. The review concludes with specific recommendations for the inclusion of a maturity indicator or maturity indicators in the construction of an international growth standard for preadolescent and adolescent children