Extended light period in the maternal circadian cycle impairs the reproductive system of the rat male offspring

Alterations in the circadian cycle are known to cause physiological disorders in the hypothalamic-pituitary-adrenal and the hypothalamic-pituitary-gonadal axes in adult individuals. Therefore, the present study aimed to evaluate whether exposure of pregnant rats to constant light can alter the reproductive system development of male offspring. The dams were divided into two groups: a light-dark group (LD), in which pregnant rats were exposed to an LD photoperiod (12 h/12 h) and a light-light (LL) group, in which pregnant rats were exposed to a photoperiod of constant light during the gestation period. After birth, offspring from both groups remained in the normal LD photoperiod (12 h/12 h) until adulthood. One male of each litter was selected and, at adulthood (postnatal day (PND) 90), the trunk blood was collected to measure plasma testosterone levels, testes and epididymis for sperm count, oxidative stress and histopathological analyses, and the spermatozoa from the vas deferens to perform the morphological and motility analyses. Results showed that a photoperiod of constant light caused a decrease in testosterone levels, epididymal weight and sperm count in the epididymis, seminiferous tubule diameter, Sertoli cell number, and normal spermatozoa number. Histopathological damage was also observed in the testes, and stereological alterations, in the LL group. In conclusion, exposure to constant light during the gestational period impairs the reproductive system of male offspring in adulthood.

Quantitative in Vitro to in Vivo Extrapolation (QIVIVE) for Predicting Reduced Anogenital Distance Produced by Anti-Androgenic Pesticides in a Rodent Model for Male Reproductive Disorders

BACKGROUND

Many pesticides can antagonize the androgen receptor (AR) or inhibit androgen synthesis in vitro but their potential to cause reproductive toxicity related to disruption of androgen action during fetal life is difficult to predict. Currently no approaches for using in vitro data to anticipate such in vivo effects exist. Prioritization schemes that limit unnecessary in vivo testing are urgently needed.

OBJECTIVES

The aim was to develop a quantitative in vitro to in vivo extrapolation (QIVIVE) approach for predicting in vivo anti-androgenicity arising from gestational exposures and manifesting as a shortened anogenital distance (AGD) in male rats.

METHODS

We built a physiologically based pharmacokinetic (PBK) model to simulate concentrations of chemicals in the fetus resulting from maternal dosing. The predicted fetal levels were compared with analytically determined concentrations, and these were judged against in vitro active concentrations for AR antagonism and androgen synthesis suppression.

RESULTS

We first evaluated our model by using in vitro and in vivo anti-androgenic data for procymidone, vinclozolin, and linuron. Our PBK model described the measured fetal concentrations of parent compounds and metabolites quite accurately (within a factor of five). We applied the model to nine current-use pesticides, all with in vitro evidence for anti-androgenicity but missing in vivo data. Seven pesticides (fludioxonil, cyprodinil, dimethomorph, imazalil, quinoxyfen, fenhexamid, o-phenylphenol) were predicted to produce a shortened AGD in male pups, whereas two (λ-cyhalothrin, pyrimethanil) were anticipated to be inactive. We tested these expectations for fludioxonil, cyprodinil, and dimethomorph and observed shortened AGD in male pups after gestational exposure. The measured fetal concentrations agreed well with PBK-modeled predictions.

DISCUSSION

Our QIVIVE model newly identified fludioxonil, cyprodinil, and dimethomorph as in vivo anti-androgens. With the examples investigated, our approach shows great promise for predicting in vivo anti-androgenicity (i.e., AGD shortening) for chemicals with in vitro activity and for minimizing unnecessary in vivo testing. https://doi.org/10.1289/EHP6774.

Spotted hyaenas and the sexual spectrum: reproductive endocrinology and development

The spotted hyaena (Crocuta crocuta) is a unique species, even amongst the Hyaenidae. Extreme clitoral development in female spotted hyaenas challenges aspects of the accepted framework of sexual differentiation and reproductive function. They lack a vulva and instead urinate, copulate and give birth through a single, long urogenital canal that traverses a clitoris superficially resembling a penis. Recent and historical evidence is reviewed to describe our changing understanding of the biology of this species. Expanding upon observations from hyaenas in nature, much has been learned from studies utilising the captive colony at the University of California, Berkeley. The steroid environment of pregnancy is shaped by placental androgen and oestrogen secretion and a late gestational increase in sex hormone binding globulin, the regulated expression and steroid-binding characteristics of which are unique within the Hyaenidae. While initial external genital development is largely free of androgenic influence, the increase in testosterone concentrations in late gestation influences foetal development. Specifically, anti-androgen (AA) treatment of pregnant females reduced the developmental influence of androgens on their foetuses, resulting in reduced androstenedione concentrations in young females and easier birth through a 'feminised' clitoris, but precluded intromission and mating by 'feminised' male offspring, and altered social interactions. Insight into the costs and benefits of androgen exposure on spotted hyaena reproductive development, endocrinology and behaviour emphasises the delicate balance that sustains reproductive success, forces a re-evaluation of how we define masculine vs feminine sexual characteristics, and motivates reflection about the representative value of model species.

The External Genitalia Score (EGS): A European Multicenter Validation Study

CONTEXT

Standardized description of external genitalia is needed in the assessment of children with atypical genitalia.

OBJECTIVES

To validate the External Genitalia Score (EGS), to present reference values for preterm and term babies up to 24 months and correlate obtained scores with anogenital distances (AGDs).

DESIGN, SETTING

A European multicenter (n = 8) validation study was conducted from July 2016 to July 2018.

PATIENTS AND METHODS

EGS is based on the external masculinization score but uses a gradual scale from female to male (range, 0-12) and terminology appropriate for both sexes. The reliability of EGS and AGDs was determined by the interclass correlation coefficient (ICC). Cross-sectional data were obtained in 686 term babies (0-24 months) and 181 preterm babies, and 111 babies with atypical genitalia.

RESULTS

The ICC of EGS in typical and atypical genitalia is excellent and good, respectively. Median EGS (10th to 90th centile) in males < 28 weeks gestation is 10 (8.6-11.5); in males 28-32 weeks 11.5 (9.2-12); in males 33-36 weeks 11.5 (10.5-12) and in full-term males 12 (10.5-12). In all female babies, EGS is 0 (0-0). The mean (SD) lower/upper AGD ratio (AGDl/u) is 0.45 (0.1), with significant difference between AGDl/u in males 0.49 (0.1) and females 0.39 (0.1) and intermediate values in differences of sex development (DSDs) 0.43 (0.1). The AGDl/u correlates with EGS in males with typical genitalia and in atypical genitalia.

CONCLUSIONS

EGS is a reliable and valid tool to describe external genitalia in premature and term babies up to 24 months. EGS correlates with AGDl/u in males. It facilitates standardized assessment, clinical decision-making and multicenter research.

Hormonal and Molecular Regulation of Phallus Differentiation in a Marsupial Tammar Wallaby

Congenital anomalies in phalluses caused by endocrine disruptors have gained a great deal of attention due to its annual increasing rate in males. However, the endocrine-driven molecular regulatory mechanism of abnormal phallus development is complex and remains largely unknown. Here, we review the direct effect of androgen and oestrogen on molecular regulation in phalluses using the marsupial tammar wallaby, whose phallus differentiation occurs after birth. We summarize and discuss the molecular mechanisms underlying phallus differentiation mediated by sonic hedgehog (SHH) at day 50 pp and phallus elongation mediated by insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3), as well as multiple phallus-regulating genes expressed after day 50 pp. We also identify hormone-responsive long non-coding RNAs (lncRNAs) that are co-expressed with their neighboring coding genes. We show that the activation of SHH and IGF1, mediated by balanced androgen receptor (AR) and estrogen receptor 1 (ESR1) signalling, initiates a complex regulatory network in males to constrain the timing of phallus differentiation and to activate the downstream genes that maintain urethral closure and phallus elongation at later stages.

[Effect of temperature on post-diapause reproductive development in Listronotus maculicollis (Coleoptera: curculionidae)]

The annual bluegrass weevil Listronotus maculicollis requires chilling exposure to terminate reproductive diapause during overwintering, but the effects of temperature on its post-diapause development in spring remain unclear. To explore this effect, overwintering adults were transferred from cold conditions (6°C/4°C, L:D 10:14) to different warm-up temperatures at L:D 12:12. When weevils were transferred to 7, 14 and 21°C in December and late January, the sizes of male and female reproductive organs were significantly smaller at 7°C than at 14 and 21°C. When weevils were transferred to 7, 9, 11, 13 and 15°C in late January, higher temperatures facilitated the post-diapause development. In both sexes, the sizes of reproductive organs and developmental rate increased with temperature. Reproductive organs did not grow significantly at 7°C in males and at 7-9°C in females, at which the percentage of developing weevils remained low. The time required for 50% of individuals to resume development was 44, 18, 13 and 8 days at 9, 11, 13 and 15°C, respectively, in males and 19, 14 and 8 days at 11, 13 and 15°C, respectively, in females. The threshold temperature for post-diapause development was 7.8°C in males, based on which 61.7 degree-days coincided with 50% of individuals developing. Under field conditions, the percentage of male and female maturity and insemination rate were low until early March, but all reached 100% by late March.

Prenatal bisphenol a and phthalate exposure are risk factors for male reproductive system development and cord blood sex hormone levels

Bisphenol A (BPA) and phthalates can adversely affect the fetal development. However, observational studies on the effects of these chemicals on fetal male reproductive system are still limited. A hundred of umbilical cord blood samples were analyzed for the levels of BPA, di-2-ethylhexyl phthalate (DEHP), mono-2-ethylhexyl phthalate (MEHP), and sex hormones. After birth, male newborns underwent physical examination that included measurements of anogenital distance, stretched penile length (SPL), and penile width. BPA, DEHP and MEHP levels were detectable in ≈99% of cord blood samples. In covariate-adjusted models, cord blood BPA levels were inversely associated with SPL of newborns and positively associated with cord blood estradiol levels. In addition, there was a significant inverse relationship between cord blood DEHP levels and anogenital distance index of newborn males. Our results suggest that in utero BPA and DEHP exposure exerted adverse effects on fetal male reproductive development and cord blood estradiol levels.

Impact of heat stress on development and fertility of Drosophila suzukii Matsumura (Diptera: Drosophilidae)

Drosophila suzukii is a globally invasive fruit pest that costs millions in yield losses and increased pest management costs. Management practices for D. suzukii currently rely heavily on calendar-based applications of broad-spectrum insecticides, but decision-based applications are theoretically possible with refined population modeling and monitoring. Temperature conditions are strongly deterministic of insect growth rates, fecundity, fertility, and resulting population densities. Therefore, information about the effects of temperature can be incorporated into population modeling to accurately predict D. suzukii population densities in the field which is crucial to maximize pesticide application efficiency and improve sustainability. Here, we investigated the effects of chronic heat stress during all of juvenile development on egg-to-adult viability and fertility. We also investigated egg-to-adult viability under heat stress after heat shock of the maternal parent. We found that heat stress during development results in lower egg-to-adult viability, and reduced lifespan and fertility for surviving adults. However, heat-shock treatment of females prior to egg laying increased the egg-to-adult viability of their eggs under heat stress. Female flies that developed at 30 °C had smaller ovaries than the untreated group and male flies had less sperm in their testes, and no sperm in their seminal vesicles. We conclude that heat stress during development is likely to have negative effect on D. suzukii population dynamics in the field. However, the intensity of such negative impact will depend on the phenotypic state of their maternal parents.

Fluoride exposure and pubertal development in children living in Mexico City

BACKGROUND

Previous animal and ecological studies have provided evidence for an earlier sexual maturation in females in relation to fluoride exposure; however, no epidemiological studies have examined the association between fluoride exposure and pubertal development in both boys and girls using individual-level biomarkers of fluoride. Capitalizing on an ongoing Mexican birth cohort study, we examined the association between concurrent urinary fluoride levels and physical markers of pubertal development in children.

METHODS

We conducted a cross-sectional study of 157 boys and 176 girls at age 10-17 years living in Mexico City. We used ion-selective electrode-based diffusion methods to assess fluoride levels in urine, adjusting for urinary specific gravity. Pubertal stages were evaluated by a trained physician. Associations of fluoride with pubertal stages and age at menarche were studied using ordinal regression and Cox proportional-hazard regression, respectively.

RESULTS

In the entire sample, the geometric mean and interquartile range (IQR) of urinary fluoride (specific gravity adjusted) were 0.59 mg/L and 0.31 mg/L, respectively. In boys, our analysis showed that a one-IQR increase in urinary fluoride was associated with later pubic hair growth (OR = 0.71, 95% CI: 0.51-0.98, p = 0.03) and genital development (OR = 0.71, 95% CI: 0.53-0.95, p = 0.02). No significant associations were found in girls, although the direction was negative.

CONCLUSIONS

Childhood fluoride exposure, at the levels observed in our study, was associated with later pubertal development among Mexican boys at age 10-17 years. Further research is needed to confirm these findings.

Self-assessment of pubertal development in a puberty cohort

Background We evaluated the inter-rater agreement between self-assessed Tanner staging and clinical examination and the intra-individual agreement of self-assessed information on various puberty markers in late adolescents from the longitudinal nationwide Puberty Cohort, a sub-cohort of the Danish National Birth Cohort (DNBC). Methods We invited 715 children from the ongoing Puberty Cohort between June 2016 and January 2017. In total, 366 children (51%) returned an add-on questionnaire identical to the questionnaire used to collect information on puberty markers, including Tanner staging, in the Puberty Cohort. Of these, 197 (54%) also participated in a clinical examination with Tanner staging. We used percentage agreement and weighted kappa statistics to evaluate the inter-rater and intra-individual agreement. Results Due to late entry, more than 75% of children were Tanner stage 4 or above at clinical examination. In girls, the inter-rater agreement for pubic hair and breast staging was 54% and 52%, respectively, yielding weighted kappas of fair strength. In boys, pubic hair and genital staging agreed in 55% and 33%, respectively, corresponding to weighted kappas of fair to moderate strength. Boys tended to underestimate genitalia staging consistently. The intra-individual agreement on Tanner staging was 75-77% in girls and 69% in boys, whereas the intra-individual agreement on axillary hair and acne was above 92%. Conclusions Self-assessment of late stages of pubertal development may be misclassified, leading to random errors in studies of puberty timing. However, self-assessment continues to serve as an important time- and cost-saving tool in large prospective puberty cohorts.

Systematic reviews and meta-analyses of human and animal evidence of prenatal diethylhexyl phthalate exposure and changes in male anogenital distance

Male reproductive alterations found in animals and humans following in utero phthalate exposure include decreased anogenital distance (AGD) and other reproductive-tract malformations. The aim of this investigation was to conduct systematic reviews of human and animal evidence of the effect of in utero exposure to diethylhexyl phthalate (DEHP) on anogenital distance (AGD) in males. PubMed, Embase, and Toxline were searched for relevant human and experimental animal studies on August 15, 2016. Search results were screened for relevance, and studies that met the inclusion criteria were evaluated for quality and data extracted for analysis. Confidence in the human and animal bodies of evidence was assessed and hazard conclusions reached by integrating evidence streams. The search yielded 6 relevant human studies and 19 animal studies. Meta-analysis of 5 human observational prospective cohort studies showed that increased maternal urinary concentrations of DEHP metabolites were associated with decreased AGD in boys (-4.07 [CI, -6.49 to -1.66] % decrease per log₁₀ rise in DEHP metabolites). Meta-analysis and meta-regression of the 19 experimental animal studies found reduced AGD with DEHP treatment, with a dose-response gradient, and with heterogeneity explained by species and strain. There is a moderate level of evidence from human investigations and a high level of data from animal studies that in utero exposure to DEHP decreases AGD. Based upon the available human and animal evidence, and consideration of mechanistic data, DEHP is presumed to be a reproductive hazard to humans on the basis of effects on AGD.

Systematic reviews and meta-analyses of human and animal evidence of prenatal diethylhexyl phthalate exposure and changes in male anogenital distance

Male reproductive alterations found in animals and humans following in utero phthalate exposure include decreased anogenital distance (AGD) and other reproductive-tract malformations. The aim of this investigation was to conduct systematic reviews of human and animal evidence of the effect of in utero exposure to diethylhexyl phthalate (DEHP) on anogenital distance (AGD) in males. PubMed, Embase, and Toxline were searched for relevant human and experimental animal studies on August 15, 2016. Search results were screened for relevance, and studies that met the inclusion criteria were evaluated for quality and data extracted for analysis. Confidence in the human and animal bodies of evidence was assessed and hazard conclusions reached by integrating evidence streams. The search yielded 6 relevant human studies and 19 animal studies. Meta-analysis of 5 human observational prospective cohort studies showed that increased maternal urinary concentrations of DEHP metabolites were associated with decreased AGD in boys (-4.07 [CI, -6.49 to -1.66] % decrease per log₁₀ rise in DEHP metabolites). Meta-analysis and meta-regression of the 19 experimental animal studies found reduced AGD with DEHP treatment, with a dose-response gradient, and with heterogeneity explained by species and strain. There is a moderate level of evidence from human investigations and a high level of data from animal studies that in utero exposure to DEHP decreases AGD. Based upon the available human and animal evidence, and consideration of mechanistic data, DEHP is presumed to be a reproductive hazard to humans on the basis of effects on AGD.

Histological structure and age-related changes in the luminal diameter of the excurrent duct system of guinea cocks (Numida meleagris) and associated changes in testosterone concentrations

As little information is available on the reproductive system of guinea fowl (Numida meleagris), a study was conducted on 49 male guinea fowl to document the histological structure and developmental changes in the luminal diameter of the ducts within the excurrent duct system and associated changes in concentrations of testosterone. Age-related changes were analyzed using the Kruskal-Wallis test and medians separated by the Mann-Whitney U-test. Tubuli recti were clearly visible in the guinea fowl and the rete testes were both intracapsular and extracapsular. Regardless of age, the luminal diameter of the proximal ductuli efferentes was the largest, while that of the connecting duct was the smallest. The luminal diameter of all ducts within the epididymal region increased (P < 0.001) monthly until 20 wk of age, and then increased marginally every month thereafter. Peripheral testosterone concentrations also peaked at 20 wk of age and declined thereafter. In adult birds, the ductus deferens enlarged posteriorly, from an average of about 279 μm cranially to 678 μm caudally. Peripheral testosterone concentrations strongly and positively correlated with the luminal diameter of ducts within the excurrent duct system. The pattern of increase in the luminal diameter of all ducts followed the pattern of testosterone secretion in these birds, which indicates that testosterone concentrations may be closely related to the development of the excurrent duct system in male guinea fowl.

External Genital Development, Urethra Formation, and Hypospadias Induction in Guinea Pig: A Double Zipper Model for Human Urethral Development

OBJECTIVE

To determine whether the guinea pig phallus would be an appropriate model of human penile development, we characterized the embryology and sexual differentiation of guinea pig external genitalia and attended to induce hypospadias in males and tubular urethra formation in females pharmacologically.

MATERIALS AND METHODS

The external genitalia of guinea pig were collected from genital swelling initiation to newborn stages, and scanning electronic microscopy and histology were performed to visualize the morphology and structure. Immunohistochemistry was used to determine the androgen receptor localization. Bicalutamide and methyltestosterone were given to pregnant dams to reveal the role and timing of androgen in guinea pig penile masculinization.

RESULTS

Canalization and dorsal-to-ventral movement of the urethral canal develops the urethral groove in both sexes, and then the males perform distal-opening-proximal-closing to form tubular urethra. More nuclear-localized androgen receptor is found in proximal genital tubercles of males than in females at (E) 29. Antiandrogen treatment at E26-E30 can cause hypospadias, and methyltestosterone administration at E27-E31 can induce tubular urethra formation in females.

CONCLUSION

Fetal development of the guinea pig phallus is homologous to that of humans. Although guinea pig has structures similar to mouse, the urethral groove and the tubular urethra formation are more similar to humans. Antiandrogen treatment causes hypospadias in males and additional androgen induces tubular urethra formation in females. Thus, guinea pig is an appropriate model for further study of cellular and molecular mechanisms involved in distal-opening-proximal-closing in tubular urethra formation and the evaluation of the pathophysiological processes of hypospadias.

Insulin-like growth factor (IGF)-like peptide and 20-hydroxyecdysone regulate the growth and development of the male genital disk through different mechanisms in the silkmoth, Bombyx mori

It is well established that ecdysteroids play pivotal roles in the regulation of insect molting and metamorphosis. However, the mechanisms by which ecdysteroids regulate the growth and development of adult organs after pupation are poorly understood. Recently, we have identified insulin-like growth factor (IGF)-like peptides (IGFLPs), which are secreted after pupation under the control of 20-hydroxyecdysone (20E). In the silkmoth, Bombyx mori, massive amounts of Bombyx-IGFLP (BIGFLP) are present in the hemolymph during pupal-adult development, suggesting its importance in the regulation of adult tissue growth. Thus, we hypothesized that the growth and development of adult tissues including imaginal disks are regulated by the combined effects of BIGFLP and 20E. In this study, we investigated the growth-promoting effects of BIGFLP and 20E using the male genital disks of B. mori cultured ex vivo, and further analyzed the cell signaling pathways mediating hormone actions. We demonstrate that 20E induces the elongation of genital disks, that both hormones stimulate protein synthesis in an additive manner, and that BIGFLP and 20E exert their effects through the insulin/IGF signaling pathway and mitogen-activated protein kinase pathway, respectively. These results show that the growth and development of the genital disk are coordinately regulated by both BIGFLP and 20E.

Steroid 5α-reductase 2 deficiency

Dihydrotestosterone is a potent androgen metabolite formed from testosterone by action of 5α-reductase isoenzymes. Mutations in the type 2 isoenzyme cause a disorder of 46,XY sex development, termed 5α-reductase type 2 deficiency and that was described forty years ago. Many mutations in the encoding gene have been reported in different ethnic groups. In affected 46,XY individuals, female external genitalia are common, but Mullerian ducts regress, and the internal urogenital tract is male. Most affected males are raised as females, but virilization occurs at puberty, and male social sex develops thereafter with high frequency. Fertility can be achieved in some affected males with assisted reproduction techniques, and adults with male social sex report a more satisfactory sex life and quality of life as compared to affected individuals with female social sex.

Phthalate affect the reproductive function and sexual behavior of male Wistar rats

Phthalates are chemicals used in many industrial products (plastic toys, shampoos, soaps), and are suspected of inducing adverse effects on the male reproductive system. In the present study, we evaluated the effects of the plasticizer di-(2-ethylhexyl)-phthalate (DEHP) on the reproductive function and sexual behavior of male offspring rats, exposed in utero and during lactation (0, 20, 100 and 500 mg/kg per day by gavage). The effects produced clearly demonstrate the ability of DEHP to disrupt the androgen-regulated development of the male reproductive tract. Absolute and relative weights of androgen-dependent tissue organs (ventral prostate and seminal vesicle) were significantly reduced at the highest dose level tested (500 mg/kg per day). Impairment of male sexual behavior (500 mg/kg per day) was also observed. Moreover, the reduction in daily sperm production and epididymal sperm counts observed after administration of the highest dose suggests an impairment of the spermatogenic processes. Most of the adverse effects reported here were observed both during puberty and during adulthood, indicating permanent effects of in utero and lactational DEHP exposure.

Rotation of male genitalia in various species of phlebotomine sandfly

Phlebotomine sandflies, vectors of Leishmania (Kinetoplastida: Trypanosomatidae) parasites that affect millions of people worldwide, breed in terrestrial biotopes. As immature stages are rarely accessible, the detection of their natural breeding sites is primarily based on findings of juvenile males with unrotated external genitalia. In males, permanent 180° rotation on the longitudinal body axis occurs soon after eclosion; however, no study has as yet addressed this aspect in detail. The present study describes the timing and duration of the rotation of male external genitalia in eight highly medically important sandfly species belonging to the genera Sergentomyia, Lutzomyia and Phlebotomus (all: Diptera: Psychodidae), kept under controlled laboratory conditions. The average duration of rotation was species-specific and varied from 12 h in Sergentomyia schwetzi to 33 h in Phlebotomus sergenti. Significant differences in rotation times were found among species, even between two closely related species of the subgenus Larroussius, Phlebotomus orientalis and Phlebotomus tobbi. The rotation of genitalia in all three studied genera was randomly oriented and similar numbers of clockwise and counter-clockwise events were observed. The study also addresses the effects of some external factors. In all species studied, rotation was not affected by the time of day of eclosion. Similarly, no differences in total rotation time were found between Phlebotomus papatasi males maintained at 25 and 20 °C, respectively. The present findings will assist in the search for natural breeding sites and in studies aimed at elucidating strategies for integrated sandfly and leishmaniasis control.

Prenatal phthalate exposures and anogenital distance in Swedish boys

BACKGROUND

Phthalates are used as plasticizers in soft polyvinyl chloride (PVC) and in a large number of consumer products. Because of reported health risks, diisononyl phthalate (DiNP) has been introduced as a replacement for di(2-ethylhexyl) phthalate (DEHP) in soft PVC. This raises concerns because animal data suggest that DiNP may have antiandrogenic properties similar to those of DEHP. The anogenital distance (AGD)--the distance from the anus to the genitals--has been used to assess reproductive toxicity.

OBJECTIVE

The objective of this study was to examine the associations between prenatal phthalate exposure and AGD in Swedish infants.

METHODS

AGD was measured in 196 boys at 21 months of age, and first-trimester urine was analyzed for 10 phthalate metabolites of DEP (diethyl phthalate), DBP (dibutyl phthalate), DEHP, BBzP (benzylbutyl phthalate), as well as DiNP and creatinine. Data on covariates were collected by questionnaires.

RESULTS

The most significant associations were found between the shorter of two AGD measures (anoscrotal distance; AGDas) and DiNP metabolites and strongest for oh-MMeOP [mono-(4-methyl-7-hydroxyloctyl) phthalate] and oxo-MMeOP [mono-(2-ethyl-5-oxohexyl) phthalate]. However, the AGDas reduction was small (4%) in relation to more than an interquartile range increase in DiNP exposure.

CONCLUSIONS

These findings call into question the safety of substituting DiNP for DEHP in soft PVC, particularly because a shorter male AGD has been shown to relate to male genital birth defects in children and impaired reproductive function in adult males and the fact that human levels of DiNP are increasing globally.

[Features of sexual development of adolescent boys in cities of Caspian region of the Republic of Kazakhstan]

The complex estimation of parameters of the sexual development of adolescent boys aged 14-16 years had been done in cities of Aktay and Atyrau, in Caspian region of Western Kazakhstan. Adolescent boys in cities of Caspian region of the Republic of Kazakhstan were found to have tendency to the delayed puberty according to Tanner score. Retarded sexual development is manifested by the some retardation in growth of genitals and escutcheon, in comparison with their peers from control group. The absence of differences in general physical development, as evidenced by anthropometry data, does not exclude the specific (elective) character of the impact of urbanogenic factors on growing male body, which is typical impact of hard metals salts.

Gonads in Histiostoma mites (Acariformes: Astigmata): structure and development

The development of male and female gonads in arrhenotokous and thelytokous species of Histiostoma was studied using transmission electron microscopy (TEM). All instars were examined: larvae, protonymphs, facultative heteromorphic deutonymphs (=hypopi), tritonymphs, and adults. In testis primordium, spermatogonia surrounding a testicular central cell (TCC) with a gradually enlarging, branched nucleus are present already at the larval stage. Spermatogonia and the TCC are connected via narrow, tubular intercellular bridges revealing that the TCC is a germline cell. Spermatocytes appear at the protonymphal stage. At the heteromorphic deutonymph stage, the testis primordium is similar to that of the protonymph, but in the tritonymph it is much larger and composed as in the adult: spermatids as well as sperm cells are present. The latter are congregated ventrally in the testis at the entrance of the deferent duct. In the larval ovary, an eccentrically located ovarian nutritive cell (ONC) is surrounded by oogonia which are connected with the ONC via tubular intercellular bridges. In later stages, the ovary grows and oocytes appear in the protonymph. Meiotic synaptonemal complexes in oocytes occur from the tritonymph stage. At about the time of the final molting, tubular intercellular bridges transform into peculiar diaphragm-crossed bridges known only in Histiostoma mites. In the adult female, growing oocytes at the end of previtellogenesis lose intercellular bridges and move ventro-laterally to the ovarian periphery towards the oviduct entrance. Vitellogenesis occurs in oviducts. Germinal cells in both the testis and ovary are embedded in a few somatic stroma cells which may be well discernible already in the larval ovary; in the testis, somatic stroma cells are evident not earlier than the end of the tritonymphal stage. The ovary has a thin wall of flat somatic cells, whereas the testis is covered by a basal lamina only. The obtained results suggest that gonads in Histiostoma and other Astigmata originate from two primordial cells only.

Development of reproductive organs in the ivory shell Babylonia japonica: observations from wild populations and laboratory-reared juveniles

We histologically examined normal differentiation and development of genital tract and gonad in the ivory shell Babylonia japonica (Buccinidae) to determine whether the formation of male-type genitalia in imposex-exhibiting females mimics the normal development of male genitalia in prosobranch gastropods. We used a wild-caught 2-year-old specimen and laboratory-reared juveniles aged 0-24 months. Gonad differentiation was unclear before age 14 months, but progressed after 16 months. Both sexes had complete genital tract and mature gonad at 20 months. However, differentiation and development occurred earlier in females than in males. Development of genital tract preceded gonad differentiation. Vas deferens morphogenesis in males resembled that in imposex-exhibiting females. These findings help to understand the morphogenesis of genital tract and gonad in prosobranch gastropods and will contribute to more in-depth studies of the mode of action of organotin compounds such as TBT and TPhT in imposex development in female prosobranch gastropods.

Morphology of the male reproductive system and sperm ultrastructure of the egg parasitoid Gryon pennsylvanicum (Ashmead) (Hymenoptera, Platygastridae)

Gryon pennsylvanicum is a platygastrid hymenopteran that has lately received increasing attention in Europe due to its possible use in biological control of the conifer seed bug pest Leptoglossus occidentalis. Here the male reproductive system and the spermatogenesis of this species, along with those of Gryon muscaeformis, are examined ultrastructurally for the first time. The male genital system is formed by a pair of testes, each containing only one follicle, a pair of accessory glands and deferent ducts connected to a single ejaculatory duct. All the stages of spermatogenesis are described in detail. Characteristic features of the Gryon spp. sperm, which are 100 μm long, are the presence of a polygonal nucleus, only one mitochondrial derivative, the occurrence of the centriole adjunct and a typical insect 9 + 9 + 2 flagellar axoneme. The single derivative, however, results from a process in which one of the two mitochondria is lost during spermiogenesis. Unlike in other insects, two centrioles occur in spermatids as a consequence of the ameiotic parthenogenesis. These characteristics stand as a valuable tool for phylogenetic inferences. Furthermore this study suggests a useful strategy for laboratory mass rearing.

Comparative analyses of reproductive structures in harvestmen (opiliones) reveal multiple transitions from courtship to precopulatory antagonism

Explaining the rapid, species-specific diversification of reproductive structures and behaviors is a long-standing goal of evolutionary biology, with recent research tending to attribute reproductive phenotypes to the evolutionary mechanisms of female mate choice or intersexual conflict. Progress in understanding these and other possible mechanisms depends, in part, on reconstructing the direction, frequency and relative timing of phenotypic evolution of male and female structures in species-rich clades. Here we examine evolution of reproductive structures in the leiobunine harvestmen or “daddy long-legs” of eastern North America, a monophyletic group that includes species in which males court females using nuptial gifts and other species that are equipped for apparent precopulatory antagonism (i.e., males with long, hardened penes and females with sclerotized pregenital barriers). We used parsimony- and Bayesian likelihood-based analyses to reconstruct character evolution in categorical reproductive traits and found that losses of ancestral gift-bearing penile sacs are strongly associated with gains of female pregenital barriers. In most cases, both events occur on the same internal branch of the phylogeny. These coevolutionary changes occurred at least four times, resulting in clade-specific designs in the penis and pregenital barrier. The discovery of convergent origins and/or enhancements of apparent precopulatory antagonism among closely related species offers an unusual opportunity to investigate how major changes in reproductive morphology have occurred. We propose new hypotheses that attribute these enhancements to changes in ecology or life history that reduce the duration of breeding seasons, an association that is consistent with female choice, sexual conflict, and/or an alternative evolutionary mechanism.

Comparison of Tamoxifen and Testosterone Propionate in Male Rats: Differential Prevention of Orchidectomy Effects on Sex Organs, Bone Mass, Growth, and the Growth Hormone-IGF-I Axis

Testis dysfunction can weaken bone and reduce muscle mass as well as impair sexual function. Testosterone (T) therapy has useful effects on sex organs, bone, and muscle in T-deficient males, but prostate concerns can preclude T use in some men. Although estrogens or other drugs can protect bone in men, gynecomastia makes estrogens unappealing, and other drugs may also be undesirable in some cases. Selective estrogen receptor modulators (SERMs) inhibit estrogen-evoked sex organ growth but mimic estrogen effects on bone and cholesterol and are advantageous for some women. SERMs may also be useful in men who must avoid androgens. As a preclinical test of this idea, tamoxifen (a SERM) and testosterone propionate (TP, a classic androgen) were compared for their efficacy in preventing varied effects of orchidectomy (ORX) in adult male rats. ORX led to ventral prostate and seminal vesicle atrophy and decreases in somatic growth, proximal tibia bone mineral density (BMD), and serum growth hormone (GH) and insulin-like growth factor I (IGF-I). ORX also increased anterior pituitary glandular kallikrein, serum cholesterol, and body temperature. Pituitary prolactin (PRL) content was unaltered. ORX effects on sex organs, somatic growth, IGF-I, cholesterol, body temperature, and pituitary kallikrein were prevented by TP at 1 mg/kg (3 doses per week), but BMD and GH were unresponsive. ORX effects on BMD and GH were prevented by TP at 10 mg/kg, but this dose evoked supraphysiologic increases in sex organs and PRL, failed to restore somatic growth, and further reduced IGF-I. Tamoxifen (1 mg/kg daily) prevented ORX effects on BMD, GH, and cholesterol without altering basal or TP-induced sex organ growth and further reduced IGF-I and somatic growth. Tamoxifen did not alter basal PRL but blocked increases caused by TP at 10 mg/kg. In summary, tamoxifen prevented ORX effects on bone and cholesterol in male rats without affecting sex organs or PRL and might be useful for men who must avoid androgens. Unexpectedly, a TP dose that replicated testis effects on sex organs and other targets had no effect on BMD or GH, and a larger TP dose that restored BMD and GH was worse at replicating normal male physiology. In addition, correlation/regression results suggested that the GH-IGF-I axis contributes to changes in BMD.

Evidence for increased tissue androgen sensitivity in neurturin knockout mice

Neurturin (NTN) is a member of the glial cell line-derived neurotrophic factor (GDNF) family and signals through GDNF family receptor alpha 2 (GFRα2). We hypothesised that epithelial atrophy reported in the reproductive organs of Ntn (Nrtn)- and Gfrα2 (Gfra2)-deficient mice could be due to NTN affecting the hormonal environment. To investigate this, we compared the reproductive organs of Ntn- and Gfrα2-deficient male mice in parallel with an analysis of their circulating reproductive hormone levels. There were no significant structural changes within the organs of the knockout mice; however, serum and intratesticular testosterone and serum LH levels were very low. To reconcile these observations, we tested androgen sensitivity by creating a dihydrotestosterone (DHT) clamp (castration plus DHT implant) to create fixed circulating levels of androgens, allowing the evaluation of androgen-sensitive endpoints. At the same serum DHT levels, serum LH levels were lower and prostate and seminal vesicle weights were higher in the Ntn knockout (NTNKO) mice than in the wild-type mice, suggesting an increased response to androgens in the accessory glands and hypothalamus and pituitary of the NTNKO mice. Testicular and pituitary responsiveness was unaffected in the NTNKO males, as determined by the response to the human chorionic gonadotrophin or GNRH analogue, leuprolide, respectively. In conclusion, our results suggest that NTN inactivation enhances androgen sensitivity in reproductive and neuroendocrine tissues, revealing a novel mechanism to influence reproductive function and the activity of other androgen-dependent tissues.

New Neotropical species of Hygronemobius Hebard, 1913 (Orthoptera: Grylloidea: Nemobiinae), including a brief discussion of male genitalia morphology and preliminary biogeographic considerations of the genus

Three new Neotropical species of Hygronemobius Hebard are described from Atlantic Forest remnants in southeastern Brazil: Hygronemnobius indaia sp. n. and Hygroneinobius iperoigae sp. n. from the state of São Paulo and Hygroneinobius guriri sp. n. from the state of Espírito Santo. We provide photographs of types and male genitalia, and discuss the morphology of male genitalia, taxonomy, calling songs and biogeographic distribution of the genus.

Dissection of the maternal effects on puberty onset by embryo transplantation in mouse

Puberty onset in mammals is affected by multiple genetic and environmental factors. Among which, the maternal effect could have played a considerable role. In our previous study, we found that the F1 offspring from reciprocal crosses between C3H/HeJ (C3H) and C57BL/6J (B6) mice differed significantly in the timing of puberty in both sexes, though they had identical genomic background. In order to dissect the causative factors to such phenomenon of maternal effect, embryos from reciprocal crosses of C3H/HeJ and C57BL/6J mice were collected and transplanted to the uterus of either strain of mothers, and the puberty onset of pups were compared between different recipient mothers and egg origins. The results showed that the male pups from C3H recipient mothers attained puberty onset earlier than those from B6 recipients significantly, while the female pups did not show such difference. On the other hand, the egg origin made no difference in the puberty onset of either sex, yet it influenced the birth weight of female pups significantly (p<0.05). The manipulation of embryo transplantation delayed the puberty onset of pups dramatically. A mitochondria substitution strain between B6 and C3H (BmC), which had the genome background of B6 and a mitochondrial hyplotype of C3H, had the same phenotype of puberty onset as B6. The integrated results indicated that the uterine environment was the major causative factors to the maternal effect on the differential puberty onset in reciprocal crosses of F1 hybrids between B6 and C3H mice.

Morphometric examination for development of reproductive organs in male cynomolgus monkeys

We previously reported on a histological classification of cynomolgus monkey testis into six grades (1, immature; 2, prepuberty; 3, onset of puberty; 4, puberty; 5, early adult; 6, adult) based on spermatogenesis development. In this investigation, the accessory reproductive organs from the same animals underwent histomorphometric examination, in addition to being examined histologically and weighed, to evaluate relationships between these parameters and the six grades. Seminiferous tubule diameter increased corresponding to the testicular maturity grade and was notably increased at grade 6. Beginning from grade 3, increases in the areas of the ductus epididymis were noted, and reserved sperm was visible in the lumen. In the prostate, the glandular lumen area per unit area showed an increase beginning from grade 3 but no clear differences between grades 4 and 6; advanced development of epithelial height was observed at grade 6. In the seminal vesicle, development of the epithelial cell layer was markedly increased at grade 6. It was concluded that development of the male accessory reproductive organs began after reserved sperm was observed in the lumen of the ductus epididymis (grade 3) and that these organs were developed notably when the testis reached sexual maturity (grade 6).

The reproductive system of Derocheilocaris typica (Crustacea, Mystacocarida)

Mystacocarids are dioecious. Their gonopores are on the medial side of the third thoracic limb. The male's paired testes lie in the thorax and abdomen. They develop from paired rows of six small follicles dorsally. In the mature animal they fill most of the abdomen. The spermatophores develop within the follicles from spermatogonia mixed with follicle cells, which support and nourish the spermatocytes and produce the seminal fluid. The short vas deferens runs along the bottom of the testes and then continues forward to the gonopore. The vas deferens has a small group of cells near the gonopore that becomes a closure mechanism. The female has reproductive cells and also support cells that provide nutrition and form the wall of the ovary and oviduct. The unpaired female ovary begins in the third thoracic segment. During maturation, the oocytes are pushed posteriorly. The enormous mature ovum extends into a caudal pocket of the ovary. Starting with its anterior end, this ovum is extruded into the short oviduct, which extends laterally and ventrally to the gonopore. During extrusion, the pocket is reabsorbed from behind. There are no accessory structures connected to the reproductive system, nor any external specializations on the third limb.

The homeodomain protein defective proventriculus is essential for male accessory gland development to enhance fecundity in Drosophila

The Drosophila male accessory gland has functions similar to those of the mammalian prostate gland and the seminal vesicle, and secretes accessory gland proteins into the seminal fluid. Each of the two lobes of the accessory gland is composed of two types of binucleate cell: about 1,000 main cells and 40 secondary cells. A well-known accessory gland protein, sex peptide, is secreted from the main cells and induces female postmating response to increase progeny production, whereas little is known about physiological significance of the secondary cells. The homeodomain transcriptional repressor Defective proventriculus (Dve) is strongly expressed in adult secondary cells, and its mutation resulted in loss of secondary cells, mononucleation of main cells, and reduced size of the accessory gland. dve mutant males had low fecundity despite the presence of sex peptide, and failed to induce the female postmating responses of increased egg laying and reduced sexual receptivity. RNAi-mediated dve knockdown males also had low fecundity with normally binucleate main cells. We provide the first evidence that secondary cells are crucial for male fecundity, and also that Dve activity is required for survival of the secondary cells. These findings provide new insights into a mechanism of fertility/fecundity.

Bridging epidemiology and model organisms to increase understanding of endocrine disrupting chemicals and human health effects

Concerning temporal trends in human reproductive health has prompted concern about the role of environmentally mediated risk factors. The population is exposed to chemicals present in air, water, food and in a variety of consumer and personal care products, subsequently multiple chemicals are found human populations around the globe. Recent reviews find that endocrine disrupting chemicals (EDCs) can adversely affect reproductive and developmental health. However, there are still many knowledge gaps. This paper reviews some of the key scientific concepts relevant to integrating information from human epidemiologic and model organisms to understand the relationship between EDC exposure and adverse human health effects. Additionally, areas of new insights which influence the interpretation of the science are briefly reviewed, including: enhanced understanding of toxicity pathways; importance of timing of exposure; contribution of multiple chemical exposures; and low dose effects. Two cases are presented, thyroid disrupting chemicals and anti-androgens chemicals, which illustrate how our knowledge of the relationship between EDCs and adverse human health effects is strengthened and data gaps reduced when we integrate findings from animal and human studies.

The genetic basis of rapidly evolving male genital morphology in Drosophila

The external genitalia are some of the most rapidly evolving morphological structures in insects. The posterior lobe of the male genital arch shows striking differences in both size and shape among closely related species of the Drosophila melanogaster species subgroup. Here, we dissect the genetic basis of posterior lobe morphology between D. mauritiana and D. sechellia, two island endemic species that last shared a common ancestor ∼300,000 years ago. We test a large collection of genome-wide homozygous D. mauritiana genetic introgressions, which collectively cover ∼50% of the genome, for their morphological effects when placed in a D. sechellia genetic background. We find several introgressions that have large effects on posterior lobe morphology and that posterior lobe size and posterior lobe shape can be separated genetically for some of the loci that specify morphology. Using next generation sequencing technology, we perform whole transcriptome gene expression analyses of the larval genital imaginal disc of D. mauritiana, D. sechellia, and two D. mauritiana-D. sechellia hybrid introgression genotypes that each have large effects on either posterior lobe size or posterior lobe shape. Many of the genes we identify as differentially expressed are expressed at levels similar to D. mauritiana in one introgression hybrid, but are expressed at levels similar to D. sechellia in the other introgression hybrid. However, we also find that both introgression hybrids express some of the same genes at levels similar to D. mauritiana, and notably, that both introgression hybrids possess genes in the insulin receptor signaling pathway, which are expressed at D. mauritiana expression levels. These results suggest the possibility that the insulin signaling pathway might integrate size and shape genetic inputs to establish differences in overall posterior lobe morphology between D. mauritiana and D. sechellia.

Shorter anogenital distance predicts poorer semen quality in young men in Rochester, New York

BACKGROUND

In male rodents, anogenital distance (AGD) provides a sensitive and continuous correlate of androgen exposure in the intrauterine environment and predicts later reproductive success. Some endocrine-disrupting chemicals can alter male reproductive tract development, including shortening AGD, in both rodents and humans. Whether AGD is related to semen quality in human is unknown.

OBJECTIVE

We examined associations between AGD and semen parameters in adult males.

METHODS

We used multiple regression analyses to model the relationships between sperm parameters and two alternative measures of AGD [from the anus to the posterior base of the scrotum (AGD(AS)) and to the cephalad insertion of the penis (AGD(AP))] in 126 volunteers in Rochester, New York.

RESULTS

AGD(AS), but not AGD(AP), was associated with sperm concentration, motility, morphology, total sperm count, and total motile count (p-values, 0.002-0.048). Men with AGD(AS) below (vs. above) the median were 7.3 times more likely (95% confidence interval, 2.5-21.6) to have a low sperm concentration (< 20 × 10⁶/mL). For a typical study participant, sperm concentrations were 34.7 × 10⁶/mL and 51.6 × 10⁶/mL at the 25th and 75th percentiles of (adjusted) AGD(AS).

CONCLUSIONS

In our population, AGD(AS) was a strong correlate of all semen parameters and a predictor of low sperm concentration. In animals, male AGD at birth reflects androgen levels during the masculinization programming window and predicts adult AGD and reproductive function. Our results suggest, therefore, that the androgenic environment during early fetal life exerts a fundamental influence on both AGD and adult sperm counts in humans, as demonstrated in rodents.

Characteristics of the male reproductive system and spermatozoa of leptophlebiidae (ephemeroptera)

This study describes morphological changes in the male reproductive system of Miroculis amazonicus (Savage & Peters) from mature nymphs to subimago stages. The sperm ultrastructure of Massartela brieni (Lestage), Farrodes carioca (Domínguez et al) and Miroculis mourei (Savage & Peters), as well as aspects of cell fragments observed in these species' subimagos deferent ducts were described. Sperm from the three species studied are aflagellated and immotile, while those from F. carioca and Ma. brieni are approximately spherical with a homogenous nucleus and acrosome. Sperm of F. carioca present two or three mitochondria located between the nucleus and the acrosome. In Ma. brieni, only one lateral mitochondria was found. Sperm from Mi. mourei are shaped as a number 'eight', with electron lucent spots inside the nucleus and two mitochondria above the acrosome. Large cell fragments containing degenerative vesicles and some sperm were observed in the deferent duct lumen of the three species. Testes of Mi. amazonicus are extremely reduced in the subimago stage, which suggests that these cell fragments originated from testes degeneration.

Male genital and wing morphology in the cactophilic sibling species Drosophila gouveai and Drosophila antonietae and their hybrids reared in different host plants

Cactophilic Drosophila flies are excellent models to study adaptation to a relatively narrow spectrum of potential host plants and host-driven evolutionary diversification. Previous studies suggested a complex genetic architecture of wing and male genital morphology in phylogenetically basal species of the D. buzzatii cluster. In this work, we investigate the effect of experimental hybridization and host plant shifts on male genital and wing morphology in D. gouveai Tidon-Sklorz and Sene and D. antonietae Tidon-Sklorz and Sene, a pair of more recently derived species. We explicitly tested the hypotheses that wing and male genital morphology in interspecific hybrids depend on the host plant in which flies were grown. Our study shows that cactus hosts exert a strong effect on genital and wing morphology and that hybrids can be clearly differentiated on the basis of wing and genital morphology from both parental species. However, the extent of morphological differentiation between hybrids and pure species as well as plasticity patterns varied across organs, suggesting a complex genetic architecture for the studied traits.

Prepubertal adrenarchal androgens and animal protein intake independently and differentially influence pubertal timing

CONTEXT

Whether adrenarche impacts on pubertal development is controversial.

OBJECTIVE

The objective of the study was to examine the associations of adrenal androgen (AA) secretion with early and late pubertal markers, independent of potential influences of dietary animal protein intake.

DESIGN AND PARTICIPANTS

This was a prospective cohort study of healthy free-living Caucasian children (n = 109) who provided both 24-h urine samples and 3-d weighed dietary records 1 and 2 yr before the biological age at take-off of the pubertal growth spurt (ATO).

MEASUREMENTS

Twenty-four-hour excretion rates of androgen (C19) metabolites quantified by gas chromatography-mass spectrometry were measured.

MAIN OUTCOMES

ATO, age at peak height velocity (APHV), age at menarche/voice break, duration of pubertal growth acceleration, and ages at Tanner stage 2 for breast (girls) and genital (boys) development (B2-G2) and pubic hair (PH2).

RESULTS

Higher adrenarchal C19 steroids predicted earlier ages at Tanner stage 2 for pubic hair (P < 0.0001) and B2-G2 (P = 0.009) as well as a shorter pubertal growth acceleration period (P = 0.001), independently of animal protein intake. Children with a higher AA secretion had a 1.5-yr earlier beginning of pubarche and a 0.8-yr earlier beginning of B2-G2 than those with a lower AA excretion. Furthermore, animal protein intake was independently negatively associated with ATO and APHV (P < 0.05 each) and tended to be negatively associated with age at menarche/voice break (P = 0.07).

CONCLUSION

A higher animal protein intake may be involved in an earlier attainment of ATO and APHV, whereas a more intensive adrenarchal process may precipitate a shorter pubertal growth spurt and a notably earlier onset of breast and genital development in girls and boys, respectively.

[Trends in puberal development of school age children living in the Metropolitan Region of Chile]

BACKGROUND

There is a worldwide tendency towards an earlier appearance of puberal development among children, associated with an increase in weight and height.

AIM

To study the trends in puberal development in Chilean school age children, between the years 1986 and 2001 and correlate it with weight and height changes.

SUBJECTS AND METHODS

In two representative samples of school age children, collected between years 1985 and 1987 (m-1986) and another between years 2000 and 2002 (m-2001), girls between 7 and 15years (958 and 935, respectively) and boys between 9 and 15 years (842 and 870 respectively), were selected. Breast development (B) in females and genital development (G) in males were classified according to Tanner stages. Weight, height, body mass index (BMI) and nutritional status (according to Centers for Disease Control/ National Center for Health Statistics (CDC/NCHS) standards) were assessed.

RESULTS

The prevalence of obesity increased four fold between 1986 and 2001. The 2001 generation had a significantly higher degree of puberal development than their counterparts studied in 1986. Compared to m-1986, m-2001 subjects had a lower mean age at puberal development stage two and three, but no differences at puberal stages 4 and 5. BMI of m-2001 subjects was significantly higher than that of m-1986 subjects at all puberal stages. The m-2001 males showed highest stature than m-1986 in all puberal stage, however, in females there is no difference in height between m-2001 and m-1986.

CONCLUSIONS

The highest BMI observed in the cohort of 2001, could be facilitating an earlier puberal development and ethnic factors could explain the sexual dimorphism in stature.

In vivo MRI evaluation of anabolic steroid precursor growth effects in a guinea pig model

Anabolic steroids are widely used to increase skeletal muscle (SM) mass and improve physical performance. Some dietary supplements also include potent steroid precursors or active steroid analogs such as nandrolone. Our previous study reported the anabolic steroid effects on SM in a castrated guinea pig model with SM measured using a highly quantitative magnetic resonance imaging (MRI) protocol. The aim of the current study was to apply this animal model and in vivo MRI protocol to evaluate the growth effects of four widely used over-the-counter testosterone and nandrolone precursors: 4-androstene-3 17-dione (androstenedione), 4-androstene-3beta 17beta-diol (4-androsdiol), 19-nor-4-androstene-3beta-17beta-diol (bolandiol) and 19-nor-4-androstene-3 17-dione (19-norandrostenedione). The results showed that providing precursor to castrated male guinea pigs led to plasma steroid levels sufficient to maintain normal SM growth. The anabolic growth effects of these specific precursors on individual and total muscle volumes, sexual organs, and total adipose tissue over a 10-week treatment period, in comparison with those in the respective positive control testosterone and nandrolone groups, were documented quantitatively by MRI.

Sfrp1 and Sfrp2 are required for normal male sexual development in mice

Secreted frizzled-related proteins (Sfrps) are antagonists of WNT signalling implicated in a variety of biological processes. However, there are no reports of a direct role for Sfrps in embryonic organogenesis in mammals. Using in vivo loss-of-function studies we report here for the first time a redundant role for Sfrp1 and Sfrp2 in embryonic sexual development of the mouse. At 16.5 dpc, male embryos lacking both genes exhibit multiple defects in gonad morphology, reproductive tract maturation and gonad positioning. Abnormal positioning of the testis appears to be due to failed gubernaculum development and an unusually close association between the cranial end of the reproductive tract and the kidney. The testes of double homozygotes are smaller than controls, contain fewer cords from the earliest stages, but still express Insl3, which encodes the hormone required for gubernacular masculinisation. Lgr8, which encodes the Insl3 receptor, is also expressed in the mutant gubernaculum, suggesting that Sfrp1/Sfrp2 signalling is not required for expression of the ligand or receptor that controls transabdominal testicular descent. Similarities between the abnormalities of embryonic sexual development in Sfrp1(-/-)Sfrp2(-/-) embryos with those exhibited by the Looptail and Wnt5a mutants suggest that disrupted non-canonical Wnt signalling may cause these defects.

Meeting report: measuring endocrine-sensitive endpoints within the first years of life

An international workshop titled "Assessing Endocrine-Related Endpoints within the First Years of Life" was held 30 April-1 May 2007, in Ottawa, Ontario, Canada. Representatives from a number of pregnancy cohort studies in North America and Europe presented options for measuring various endocrine-sensitive endpoints in early life and discussed issues related to performing and using those measures. The workshop focused on measuring reproductive tract developmental endpoints [e.g., anogenital distance (AGD)], endocrine status, and infant anthropometry. To the extent possible, workshop participants strove to develop or recommend standardized measurements that would allow comparisons and pooling of data across studies. The recommended outcomes include thigh fat fold, breast size, vaginal cytology, AGD, location of the testis, testicular size, and growth of the penis, with most of the discussion focusing on the genital exam. Although a number of outcome measures recommended during the genital exam have been associated with exposure to endocrine-disrupting chemicals, little is known about how predictive these effects are of later reproductive health or other chronic health conditions.

[Genes related with male gonadal morphogenesis in mammals]

Gene expressions are sex-specific in the sex development of mammals. Different genes express in different phases and tend to change with the time. The functions of some genes, such as SRY, SOX9, SOX8, DAX1, and FGF9, have already been defined in male gonadal morphogenesis. This paper presents a review of the genes involved in the formation of the male gonad in mammals.

Are there short cuts to pubertal assessments? Self-reported and assessed group differences in pubertal development in African adolescents

PURPOSE

Self-rating of pubertal development using the Pubertal Development Scale (PDS) is recommended as a noninvasive assessment of puberty in large community-based surveys of adolescent development and behavior. The objective of this study was to assess the reliability of the PDS for the first time among urban, Black South African youth.

METHODS

The concordance between adolescents' self-assessment of sexual maturation using the PDS and those of an expert rating by a trained health professional using the Sexual Maturation Scale (SMS) were determined in a group (n = 182; 49% female) of Black South African youth aged between 10 and 18 years recruited from schools in Soweto, South Africa. Furthermore, the concordance between adolescents' self-assessment of puberty using the PDS and a previously validated self-assessment technique using SMS was also determined in a large group (n = 1388; 53% female) of young adolescents aged 13 years old participating in a birth cohort from Soweto-Johannesburg.

RESULTS

The convergent validity of PDS proved to be poor with several PDS items (facial hair, skin change, and growth) proving unreliable both within the school survey across the different age groups when compared to SMS (kappa coefficient of 0.34 for females and undetermined for males), as well as, within the cohort of 13-year-olds (kappa coefficient of 0.16 for females and 0.19 for males).

CONCLUSIONS

The results suggest that there may be as yet undocumented differences in pubertal manifestations and awareness of these manifestations, especially facial hair and skin change (acne), among urban, Black South African youth that make the PDS self-assessment less reliable as a pubertal assessment tool in multiethnic community-based research.

Estrogen regulation of the male reproductive tract in the frog, Rana esculenta: a role in Fra-1 activation in peritubular myoid cells and in sperm release

Endogenous and environmental estrogens have been proved to affect male reproduction in vertebrates. Both positive and negative effects in the regulation of the reproductive tract have been described. Since it is well known that amphibians represent a useful model to study several aspects concerning reproductive activity, we have taken advantage of the frog, Rana esculenta, to study the involvement of estrogens in sperm release. We show here that pituitary hormones increased the number of peritubular myoid cells (PMCs) expressing Fra-1 and induced testicular morphological changes related to sperm release. The estrogen antagonist ICI182-780 counteracted the hypophysis driven effects. In vivo and in vitro experiments demonstrated that 17beta-Estradiol acted directly on the testis to switch-on Fra-1 in PMCs. Furthermore, impairment of estrogen activity significantly reduced sperm release mainly affecting the detachment of spermatozoa from Sertoli cells (spermiation). Therefore, estrogens can be considered a new entry in the list of substances involved in spermiation.

Spatial and temporal variation in size of polar bear (Ursus maritimus) sexual organs and its use in pollution and climate change studies

Sexual organs and their development are susceptible to atmospheric transported environmental xenoendocrine pollutants and climate change (food availability). We therefore investigated sexual organs from 55 male and 44 female East Greenland polar bears (Ursus maritimus) to obtain information about growth/size and sexual maturity. Then, the genitalia size was compared with those previously reported from Canadian and Svalbard polar bears. Growth models showed that East Greenland male polar bears reached sexual maturity around 7 years of age and females around 4 years of age. When comparing East Greenland and Svalbard polar bears, the size of baculum and uterus were significantly lower in the East Greenland polar bears (ANOVA: all p < 0.05). Based on previously published baculum mean values from Canadian polar bears, a similar baculum pattern was found for East Greenland vs. Canadian polar bears. It is speculated whether this could be a result of the general high variation in polar bear body size, temporal distribution patterns of anthropogenic long-range transported persistent organic pollutants or climate change (decreasing food availability). The present investigation represents conservation and background data for future spatial and temporal assessments of hunting, pollution and climate change scenarios.

Amino-terminal propeptide of C-type natriuretic peptide and linear growth in children: effects of puberty, testosterone, and growth hormone

CONTEXT

C-type natriuretic peptide (CNP), a paracrine factor of the growth plate, plays a key role in stimulating bone growth. The amino-terminal propeptide of CNP (NTproCNP) is produced in equimolar amounts with CNP and is measurable in plasma, providing a potential biomarker for growth plate activity and, hence, linear growth.

OBJECTIVE

We explored the effects of puberty, testosterone, and GH treatment on NTproCNP levels in normal and short-statured children.

DESIGN

This was a retrospective analysis of samples obtained during previous studies.

SETTING

The study was conducted at a pediatric clinical research center.

SUBJECTS

Children with short stature due to GH deficiency, idiopathic short stature (ISS), or constitutional delay of growth and maturation (CDGM) were studied (n = 37). A cohort of normal-statured adolescent boys was also studied (n = 23).

INTERVENTIONS

Children with GH deficiency and ISS were studied before and during testosterone and/or GH treatment. Boys with CDGM and healthy controls were studied once.

MAIN OUTCOME MEASURES

The main outcomes were NTproCNP levels before and during growth-promoting therapy and during pubertal growth.

RESULTS

Children with short stature due to GH deficiency, ISS, or CDGM had comparable baseline levels of NTproCNP, and levels increased markedly in response to GH or testosterone treatment. In boys with CDGM, levels were comparable with height-matched controls but were less than those from age-matched controls. In healthy boys, NTproCNP appears to peak with the pubertal growth spurt.

CONCLUSIONS

NTproCNP levels increase during growth-promoting therapy and are increased during puberty in boys. This novel biomarker of growth may have clinical utility in the evaluation of children with short stature and for monitoring growth-promoting therapy.

Effects of altered food intake during pubertal development in male and female wistar rats

The U.S. Environmental Protection Agency is currently validating assays that will be used in a Tier I Screening Battery to detect endocrine disrupting chemicals. A primary concern with the Protocols for the Assessment of Pubertal Development and Thyroid Function in Juvenile Male and Female Rats is that a nonspecific reduction in body weight (BWT) during the exposure period may potentially confound the interpretation of effects on the endocrine endpoints. Wistar rats were underfed 10, 20, 30, or 40% less than the ad libitum food consumed by controls from postnatal days (PNDs) 22 to 42 (females) or PNDs 23 to 53 (males). Terminal BWT of females and males were 2, 4, 12, and 19% and 2, 6, 9, and 19% lower than controls, respectively. In the females, neither the age of pubertal onset nor any of the thyroid hormone endpoints were affected by food restriction (FR) that led to a 12% decrease in BWT. Similarly, none of the male reproductive endpoints examined were altered by FR that led to a 9% BWT decrease. However, decreased triiodothyronine and thyroxin was observed in FR males with a 9% reduced BWT. While these data support the use of the maximum tolerated dose for BWT (10%) for the female protocol, effects on the male thyroid endpoints indicate that a slightly lower limit (<or= 6% BWT loss) may be appropriate for the male pubertal protocol, and in cases where the BWT loss approaches 9-10%, additional studies and/or a weight of evidence approach should be used when interpreting the data for the thyroid endpoints.

Adverse effect of organophosphate compounds, dichlorvos and chlorpyrifos in the reproductive tissues of transgenic Drosophila melanogaster: 70kDa heat shock protein as a marker of cellular damage

The study highlights the adverse effects of organophosphate compounds dichlorvos and chlorpyrifos on reproduction in Drosophila. Freshly eclosed first instar larvae of Drosophila melanogaster transgenic for hsp70 (hsp70-lacZ) Bg(9) were fed on 0.015-150.0ppb dichlorvos and chlorpyrifos mixed food. Virgin flies eclosing from the normal and contaminated food were pair-mated to examine the effect of the test chemicals on reproduction of the exposed organisms. Expression of hsp70, sex peptide (SP or Acp70A), accessory gland protein (Acp36DE) and tissue damage was examined in reproductive organs of adult fly. Exposed organisms exhibited a dose-dependent significantly reduced reproductive outcome and males were found to be more sensitive than females. Hsp70 expression was restricted only within the testis lobes of male fly while it was not induced in the ovary of the female. In concurrence with absence of hsp70 expression in the accessory glands of male fly, tissue damage was evident in them. Acp70A and Acp36DE expression were found to be significantly downregulated at the higher concentrations of the test chemicals. The study suggests that (i) dichlorvos is more deleterious to fly reproduction compared to chlorpyrifos with an adverse effect on Acp70A and Acp36DE expression required to facilitate normal reproduction; (ii) hsp70 may be used as a marker of cellular damage against dichlorvos and chlorpyrifos in Drosophila.