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Indian Pediatrics Jun 2006
Topics: Adolescent; Age Factors; Child; Female; Global Health; Humans; Male; Puberty; Puberty, Precocious; Rural Population; Sexual Maturation; Time Factors
PubMed: 16820656
DOI: No ID Found -
Biology of Reproduction Jan 2019Acquisition of reproductive maturity involves one of the most important series of developmental events in an organism's life. The beginning of adolescence is marked by... (Review)
Review
Acquisition of reproductive maturity involves one of the most important series of developmental events in an organism's life. The beginning of adolescence is marked by the onset of puberty. Puberty is the continuum of physical changes through which an infantile body matures into an adult capable of reproduction. This is a period of increased brain plasticity, where processes of re-wiring, neuronal proliferation, and pruning are enhanced. The initiation of mammalian puberty requires an increased pulsatile release of gonadotropin-releasing hormone from the hypothalamus. Puberty is regulated by neuroendocrine, genetic, and epigenetic factors. The maturation and function of the reproductive axis are highly sensitive to the energy status of the organism and sophisticated mechanisms exist to inhibit the axis in unfavorable energetic or metabolic conditions.In this review, we will focus on the impact of alcohol and obesity on reproductive outcomes, with emphasis on their effects on the timing of puberty. In the case of obesity, conflictive data are found, and while in females the association of overnutrition with advanced onset of puberty is consistent, in males, discrepant results have been reported. Concerning alcohol exposure, compelling evidence has documented a delay in the onset of puberty. We will present here data from both clinical studies and research involving preclinical models, which do not only delineate the impact of these conditions on the timing of puberty and potential underlying mechanisms, but that may help to define better strategies for the rational management of puberty disorders, especially of metabolic origin.
Topics: Adolescent; Adult; Age of Onset; Alcohol Drinking; Animals; Ethanol; Female; Humans; Male; Pediatric Obesity; Puberty; Sexual Maturation; Time Factors
PubMed: 30052777
DOI: 10.1093/biolre/ioy168 -
Philosophical Transactions of the Royal... Dec 2006Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual...
Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies. Stress during early development can retard or accelerate sexual maturation and reproduction. Early age of menarche is associated with absence of younger siblings, absence of a father figure during early life and increased weight. Father absence during early life is also associated with early marriage, pregnancy and divorce. Choice of partner characteristics is critical to successful implementation of sexual strategies. It has been suggested that sexually dimorphic traits (including those evident in the face) signal high-quality immune function and reproductive status. Masculinity in males has also been associated with low investment in mate and offspring. Thus, women's reproductive strategy should be matched to the probability of male investment, hence to male masculinity. Our review leads us to predict associations between the rate of sexual maturation and adult preferences for facial characteristics (enhanced sexual dimorphism and attractiveness). We find for men, engaging in sex at an early age is related to an increased preference for feminized female faces. Similarly, for women, the earlier the age of first sex the greater the preference for masculinity in opposite-sex faces. When we controlled sexual dimorphism in male faces, the speed of sexual development in women was not associated with differences in preference for male facial attractiveness. These developmental influences on partner choice were not mediated by self-rated attractiveness or parental relationships. We conclude that individuals assort in preferences based on the rapidity of their sexual development. Fast developing individuals prefer opposite-sex partners with an increased level of sexually dimorphic facial characteristics.
Topics: Adolescent; Adult; Aging; Beauty; Face; Female; Humans; Male; Reproduction; Sex Characteristics; Sexual Maturation
PubMed: 17118929
DOI: 10.1098/rstb.2006.1936 -
Animal Reproduction Science Feb 2011Toll-like receptors (TLRs) are a critical component of the innate immune response in many vertebrates, including avian species. The recent findings of chicken TLRs...
Toll-like receptors (TLRs) are a critical component of the innate immune response in many vertebrates, including avian species. The recent findings of chicken TLRs (cTLRs) expression in ovarian follicles and in the chicken ovary in vivo, as well as the changes in their expression in response to lipopolysaccharide or Salmonella enteritidis (SE) infection, have broad implications for reproductive physiology and for the prevention of transmission of zoonotic diseases to humans through the consumption of contaminated poultry eggs. Because the main route of egg contamination is from infection of the oviduct and mainly from the vagina, the aim of this study was to investigate the expression of the ten cTLRs identified to date in the chicken oviduct in vivo, to determine whether sexual maturation affects their mRNA abundance and to investigate whether SE infection alters the expression of TLRs in the chicken vagina. RNA was extracted from the vagina of healthy prepubertal, sexually mature and aged birds, and from sexually mature and aged SE infected birds. RT-PCR analysis revealed that all types of cTLRs apart from TLR1-1 were expressed in the vagina of sexually mature birds. Quantitative real-time PCR analysis revealed that the mRNA abundance of TLR2-1, 2-2 and 4 differ with respect to sexual maturation in the chicken vagina. SE infection resulted in a significant induction of TLR5 and 15 in the vagina of sexually mature birds, and in a significant induction of TLR2-1, 4 and 15 in the vagina of aged birds, while a significant down-regulation was observed for TLR7 in the vagina of sexually mature birds. These findings suggest that a TLR mediated immune response mechanism exists in the chicken vagina, playing a crucial role in preventing microbial pathogens from being incorporated into newly forming eggs.
Topics: Age Factors; Animals; Chickens; Female; Gene Expression Regulation; Poultry Diseases; Salmonella Infections, Animal; Sexual Maturation; Toll-Like Receptors; Vagina
PubMed: 21292412
DOI: 10.1016/j.anireprosci.2011.01.010 -
Birth Defects Research Feb 2018The postnatal development of the female reproductive system in laboratory animals and humans is reviewed. To enable a meaningful species comparison of the developing... (Comparative Study)
Comparative Study Review
The postnatal development of the female reproductive system in laboratory animals and humans is reviewed. To enable a meaningful species comparison of the developing female reproductive system, common definitions of developmental processes were established with a focus made on aspects that are similar across species. A species comparison of the key endocrine, morphologic, and functional (onset of ovarian cycles and ability to reproduce) features of postnatal development of the female reproductive system is provided for human, nonhuman primate, dog, rat, and also mouse, minipig, and rabbit where possible. Species differences in the timing and control of female sexual maturation are highlighted. Additionally, a species comparison of the type and timing of female reproductive ovarian cycles was compiled. Human development provided the frame of reference, and then other common laboratory species were compared. The comparison has inherent challenges because the processes involved and sequence of events can differ greatly across species. Broad strokes were taken to assign a particular average age to an event and are to be used with caution. Methods of evaluation of postnatal female reproductive development in laboratory animals are discussed. Lastly, control rodent data from one of the author's laboratory on vaginal opening, first estrus, estrous cyclicity, and the histopathology involved with the developing female rat and mouse are presented. The information provided in this review is intended to be a resource for the design and interpretation of juvenile animal toxicity testing and ultimately, the relevance of the data to characterize potential risks for women and girls. Birth Defects Research 110:163-189, 2018. © 2017 Wiley Periodicals, Inc.
Topics: Animals; Female; Genitalia, Female; Humans; Sexual Maturation; Species Specificity
PubMed: 29243395
DOI: 10.1002/bdr2.1132 -
The Journal of Sports Medicine and... Mar 2005Pubertal changes constitute a background for development of motor abilities and flexibility as an important component of physical fitness. The aim of the present study...
AIM
Pubertal changes constitute a background for development of motor abilities and flexibility as an important component of physical fitness. The aim of the present study was to investigate whether the flexibility is actually related to sexual maturation stages in adolescent boys.
METHODS
This cross-sectional study was conducted on 69 healthy boys aged 14 years. Before testing, all participants performed a 3 min warm up and static stretch routine, emphasizing the lower body. The flexibility tests were performed in a counterbalanced design. Sit-and-reach test and goniometric measurement of hamstring flexibility was administered. The results of flexibility tests and body measures were analysed for cross-sectional comparison. Groups were formed according to Tanner's classification and consisted of boys in Stage II, III, IV, V, respectively.
RESULTS
The results of sit and reach test scores and goniometric measurements did not correlate with age in months, height, weight and BMI; and furthermore they did not correlate with the sexual maturation stages (p>0.05). The sit and reach test scores were significantly correlated with goniometric measurements (right: r=0.653, p=0.00; left: r=0.638, p=0.00).
CONCLUSIONS
The results suggest that sexual maturation stages in pubertal period would not be effective in determining the flexibility. Besides, sexual maturation is not a cause of decreased flexibility in adolescent boys aged 14 years.
Topics: Adolescent; Analysis of Variance; Cross-Sectional Studies; Humans; Male; Motor Skills; Muscle, Skeletal; Pliability; Range of Motion, Articular; Sexual Maturation
PubMed: 16208291
DOI: No ID Found -
Poultry Science Oct 2019As broiler breeders face increased reproductive challenges specifically related to overfeeding, a clear understanding of the physiological effects of BW and rearing...
As broiler breeders face increased reproductive challenges specifically related to overfeeding, a clear understanding of the physiological effects of BW and rearing photoperiod on reproductive development is needed. The objective was to use mathematical models to compare plasma estradiol-17β (E2) concentration to characterize the effect of BW and rearing photoperiod on E2 levels. A 2 × 3 factorial arrangement of treatments was used. Hens (n = 180) were fed with a precision feeding system to allocate feed individually to achieve the breeder-recommended BW curve (Standard) or to a BW curve reaching the 21 wk target at 18 wk (High). Hens were on 8L:16D, 10L:14D, or 12L:12D photoschedules during rearing and were photostimulated at 21 wk. Age at first egg (AFE) was recorded. Plasma E2 levels were determined weekly between week 20 and 28. Two modified Gompertz models described E2 level as a function of (a) chronological or (b) physiological (relative to AFE) age. Timing of E2-inflection point was compared between models and treatments. Differences were reported as significant at P ≤ 0.05. The chronological age model inferred that High BW reduced the duration between the E2-inflection point and AFE, whereas the physiological age model inferred that High BW only reduced the duration between photostimulation and the E2-inflection point. Hens on the Standard BW treatment had a longer period between photostimulation and the E2-inflection point compared to hens on the High-BW treatment (11.03 vs. 1.50 wk, respectively, based on physiological age). Hens on the 12L:12D photoschedule had a longer period between photostimulation and the E2-inflection point compared to hens on the 8L:16D or 10L:14D photoschedule, both in the Standard and High BW (28.91 vs. 1.78 and 2.40 wk, 2.65 vs. 0.93 and 0.94 wk, respectively, based on physiological age). The described methodology and results provide quantitative insight into E2 dynamics and serves as a model for future endocrinological studies in poultry reproduction.
Topics: Animals; Body Weight; Chickens; Estradiol; Female; Photic Stimulation; Photoperiod; Sexual Maturation
PubMed: 31002115
DOI: 10.3382/ps/pez224 -
Marine Biotechnology (New York, N.Y.) Feb 2014In Atlantic salmon aquaculture, early sexual maturation represents a major problem for producers. This is especially true for grilse, which mature after one sea winter...
In Atlantic salmon aquaculture, early sexual maturation represents a major problem for producers. This is especially true for grilse, which mature after one sea winter before reaching a desirable harvest weight, rather than after two sea winters. Salmon maturing as grilse have a much lower market value than later maturing individuals. For this reason, most companies desire fish that grow fast and mature late. Marker-assisted selection has the potential to improve the efficiency of selection against early maturation and for late sexual maturation; however, studies identifying age of sexual maturation-related genetic markers are lacking for Atlantic salmon. Therefore, we used a 6.5K single-nucleotide polymorphism (SNP) array to genotype five families from the Mainstream Canada broodstock program and search for SNPs associated with early (grilsing) or late sexual maturation. There were 529 SNP loci that were variable across all five families, and this was the set that was used for quantitative trait loci (QTL) analysis. GridQTL identified two chromosomes, Ssa10 and Ssa21, containing QTL related to grilsing. In contrast, only one QTL, on Ssa18, was found linked to late maturation in Atlantic salmon. Our previous work on these five families did not identify genome-wide significant growth-related QTL on Ssa10, Ssa21, or Ssa18. Therefore, taken together, these results suggest that both grilsing and late sexual maturation are controlled independently of one another and also from growth-related traits. The identification of genomic regions associated with grilsing or late sexual maturation provide an opportunity to incorporate this information into selective breeding programs that will enhance Atlantic salmon farming.
Topics: Animals; Breeding; Canada; Chromosome Mapping; Genetic Markers; Genotype; Life Cycle Stages; Phenotype; Polymorphism, Single Nucleotide; Quantitative Trait Loci; Salmo salar; Sexual Maturation
PubMed: 23912817
DOI: 10.1007/s10126-013-9530-3 -
Journal of Fish Biology Apr 2024This study investigated the relationship between the size, condition, year class, family, and sexual maturity of Atlantic salmon (Salmo salar) using data collected in an...
This study investigated the relationship between the size, condition, year class, family, and sexual maturity of Atlantic salmon (Salmo salar) using data collected in an aquaculture selective breeding programme. Males that were sexually mature at 2 years of age (maiden spawn) have, on average, greater fork length and condition factor (K) at 1 year of age than their immature counterparts. For every 10-mm increase in fork length or 0.1 increase in K at 1 year of age, the odds of sexual maturity at 2 years of age increased by 1.48 or 1.22 times, respectively. Females that were sexually mature at 3 years of age (maiden spawn) have, on average, greater fork length and K at 2 years of age than their immature counterparts. For every 10-mm increase in fork length or 0.1 increase in K at 2 years of age, the odds of sexual maturity at 3 years of age increased by 1.06 or 1.44 times, respectively. The family explained 34.93% of the variation in sexual maturity among 2-year-old males that was not attributable to the average effects of fork length and K at 1 year of age and year class. The proportion of variation in sexual maturity among 3-year-old females explained by the family could not be investigated. These findings suggest that the onset of sexual maturation in Atlantic salmon is conditional on performance (with respect to energy availability) surpassing a threshold, the magnitude of which can vary between families and is determined by a genetic component. This could support the application of genetic selection to promote or inhibit the onset of sexual maturation in farmed stocks.
Topics: Humans; Male; Female; Animals; Sexual Maturation; Salmo salar; Aquaculture
PubMed: 37996984
DOI: 10.1111/jfb.15626 -
Annals of Human Biology 1998Girls actively training in sport (n=23) and girls not active in sport (n=26) were compared in terms of ages at peak height velocity (PHV) and menarche, the interval...
Girls actively training in sport (n=23) and girls not active in sport (n=26) were compared in terms of ages at peak height velocity (PHV) and menarche, the interval between ages at PHV and menarche, and ages at attaining stages of pubic hair and breast and the estimated duration of the stages. Subjects were longitudinally followed from about 11-18 years of age. Stature and weight were measured and stages of pubic hair and breast development were rated at approximately quarterly intervals between the initial observation and 14 years of age, at semiannual intervals until 16 years, and at irregular intervals subsequently. Age at menarche was obtained prospectively. The active girls trained 12 hours per week in rowing, track and swimming for an average of 3.9+/-1.2 years during puberty and the growth spurt. Longitudinal stature records for individual girls were fitted with kernel regression to estimate age at PHV (years). The interval between age at PHV and age at menarche was calculated. Ages at appearance of pubic hair and breast stages 3, 4 and 5 were calculated by back-interpolation, while intervals between stages 3 and 4 were calculated after log 10 transformation. Peak height velocity and menarche occur, on average, slightly later in girls active in sport, but the differences are not significant. The interval between PHV and menarche, PHV (cm/year), ages at attaining pubic hair and breast stages 3, 4 and 5, and estimated intervals between adjacent stages also do not significantly differ between girls actively training in sport and those not active in sport. Thus, regular training in sport during puberty and the adolescent spurt does not apparently influence the timing and progression of somatic and sexual maturation in girls.
Topics: Adolescent; Child; Female; Humans; Longitudinal Studies; Prospective Studies; Sexual Maturation; Sports
PubMed: 9741485
DOI: 10.1080/03014469800006662