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Fetal and Pediatric Pathology 2005Puberty is the interval in the life cycle during which the child becomes an adult. It is heralded by physical changes such as acceleration of linear growth and... (Review)
Review
Puberty is the interval in the life cycle during which the child becomes an adult. It is heralded by physical changes such as acceleration of linear growth and appearance of secondary sexual characteristics, capped by attainment of reproductive capability, and orchestrated by increases in the secretion of hypothalamic, pituitary, and gonadal hormones. This article discusses selected historical and contemporary aspects of isosexual precocious puberty, i.e., the development of sexual characteristics prior to the usual age of pubertal onset.
Topics: Child; Female; History, 20th Century; Humans; Male; Puberty, Precocious; Sexual Maturation
PubMed: 16175751
DOI: 10.1080/15227950590961207 -
Journal of Evolutionary Biology Mar 2009The trade-off between gametes and soma is central to life history evolution. Oosorption has been proposed as a mechanism by which females can redirect nutrients invested...
The trade-off between gametes and soma is central to life history evolution. Oosorption has been proposed as a mechanism by which females can redirect nutrients invested in oocytes into survival when conditions for reproduction are poor. Although positive correlations between oocyte degradation and lifespan have been documented in oviparous insects, the adaptive significance of this process in species with more complex reproductive biology has not been explored. Further, environmental condition is a multivariate state, and combinations of environmental stresses may interact in unpredictable ways. Previous work on the ovoviviparous cockroach, Nauphoeta cinerea, revealed that females manipulated to mate late relative to sexual maturation experience age-related loss in fecundity because of loss of viable oocytes via apoptosis. This loss in fecundity is correlated with a reduction in female mate choice. Food deprivation while mating is delayed further increases levels of oocyte apoptosis, but the relationship between starvation-induced apoptosis and life history are unknown. To investigate this, virgin females were either fed or starved from eclosion until provided with a mate at a time known to be suboptimal for fertility. Following mating, females were fed for the duration of their lifespan. We measured lifetime reproductive performance. Contrary to predictions, under conditions of delayed mating opportunity, starved females had greater fecundity, gave birth to more high-quality offspring and had increased longevity compared with that of fed females. We suggest that understanding proximal mechanisms underlying life history trade-offs, including the function of oocyte apoptosis, and how these mechanisms respond to varied environmental conditions is critical.
Topics: Animals; Diet; Female; Fertility; Male; Random Allocation; Sexual Behavior, Animal; Sexual Maturation; Starvation; Time Factors
PubMed: 19170814
DOI: 10.1111/j.1420-9101.2008.01671.x -
Journal of Economic Entomology Apr 2016It has been demonstrated that the application of juvenile hormone analog, methoprene, reduces the time required for sexual maturation and enhances mating success in...
It has been demonstrated that the application of juvenile hormone analog, methoprene, reduces the time required for sexual maturation and enhances mating success in several species of tephritid fruit flies. This study examined the effect of different concentrations of methoprene incorporated into the diet of adult flies and distinct sugar:protein (S:P) ratios on sexual maturity and pheromone emission of Anastrepha obliqua males. Diets with 0.2 and 0.5% of methoprene accelerated sexual maturation of males compared with untreated males. In subsequent assays, the enhancement of male pheromone emission and sexual maturation by the incorporation of 0.02% methoprene into a 24:1 (S: P) diet was confirmed. Among the volatiles released by males, (Z)-3-nonenol and (Z,Z)-3,6-nonadienol were emitted at higher quantities by flies treated with methoprene than untreated ones. The results show that methoprene accelerates sexual maturation of mass-reared A. obliqua males and increases their mating propensity. This would reduce the time required to attain sexual maturation by sterile males, thus decreasing fly handling costs and improving the efficacy of the sterile insect technique.
Topics: Animals; Female; Male; Methoprene; Pest Control, Biological; Pheromones; Sexual Behavior, Animal; Sexual Maturation; Tephritidae
PubMed: 26797870
DOI: 10.1093/jee/tov404 -
The Journal of Adolescent Health :... Apr 2011Sexual maturation assessment using physical examination may no longer be feasible in some large epidemiologic surveys, such as National Health and Nutrition Examination...
PURPOSE
Sexual maturation assessment using physical examination may no longer be feasible in some large epidemiologic surveys, such as National Health and Nutrition Examination Survey, because of the sensitivity of the examination and privacy concerns. This study tested the feasibility of a new automated audio computer-assisted self-interview (ACASI) module for children and adolescents for self-assessment of sexual maturation.
METHODS
A cross-sectional feasibility study was conducted at a large urban children/adolescent clinic in Washington D.C. Self-assessed sexual maturation (Tanner stages) was reported by 234 youths (119 boys and 115 girls) aged 8-18 years by using the ACASI module. Girls assessed their breast and pubic hair development, and boys assessed their genital and pubic hair development. Self-assessments were compared with Tanner stages recorded by clinical examiners during routine well-child physical examinations conducted on the same day.
RESULTS
There was good/excellent agreement between boy's self-assessment and the examiner's assessment of their genital stage (weighted κ: .65, 95% confidence interval [CI]: .55-.75) and pubic hair stage (weighted κ: .78, CI: .70-.86). There was excellent agreement between girl's self-assessment and the examiner's assessment of their breast stage (weighted κ: .81, CI: .74-.87) and pubic hair stage (weighted κ: .78, CI: .71-.86).
CONCLUSION
The ACASI method is a feasible method of pubertal self-assessment for participants as young as 8 years in large epidemiologic surveys. However, additional testing is needed to determine the validity of this ACASI module.
Topics: Adolescent; Audiovisual Aids; Child; Cross-Sectional Studies; District of Columbia; Feasibility Studies; Female; Humans; Interviews as Topic; Male; Self Concept; Sexual Maturation
PubMed: 21402259
DOI: 10.1016/j.jadohealth.2010.09.020 -
Invertebrate Neuroscience : IN Jun 2013The classic study of Wells and Wells on the control of reproduction in Octopus demonstrated that the activity of the subpedunculate lobe of the brain and environmental... (Review)
Review
The classic study of Wells and Wells on the control of reproduction in Octopus demonstrated that the activity of the subpedunculate lobe of the brain and environmental illumination both inhibit the release of an unknown gonadotropin from the optic gland. This inhibitory control may be exerted by the neuropeptide Phe-Met-Arg-Phe-NH₂ (FMRFamide). It was later demonstrated that the olfactory lobe is also likely to be involved in the control of optic gland activity. The presence of gonadotropin-releasing hormone in the olfactory lobe suggested that it might exert an excitatory action on optic gland activity. Other neuropeptides have now been localised in the olfactory lobe: neuropeptide Y, galanin, corticotropin-releasing factor, Ala-Pro-Gly-Trp-NH₂ (APGWamide), as well as steroidogenic enzymes and an oestrogen receptor orthologue. This supports the hypothesis that this lobe may also play a part in the control of reproduction in Octopus. The olfactory lobe receives distant chemical stimuli and also appears to be an integrative centre containing a variety of neuropeptides involved in controlling the onset of sexual maturation of Octopus, via the optic gland hormone. This review attempts to summarise current knowledge about the role of the olfactory lobe and optic gland in the control of sexual maturation in Octopus, in the light of new findings and in the context of molluscan comparative physiology.
Topics: Animals; Brain; Gonadal Steroid Hormones; Neuropeptides; Octopodiformes; Reproduction; Sexual Maturation
PubMed: 23558706
DOI: 10.1007/s10158-013-0149-x -
European Archives of Psychiatry and... Jun 2008This paper reviews aspects of Letten F. Saugstad's Maturation Theory in relation to the Kraepelinian dichotomy and psychiatric classification. The maturation theory is... (Review)
Review
This paper reviews aspects of Letten F. Saugstad's Maturation Theory in relation to the Kraepelinian dichotomy and psychiatric classification. The maturation theory is based on existing neuroscience, cross-national and mental health case register data and offers an innovative alternative to current etiological formulations. The maturational theory holds (1) that manic depressive illness relates to early maturation and (2) the schizophrenic syndrome relates to late maturation. The foundation of these processes lies in cerebral pruning of excitatory synapses particularly at puberty but also at a number of earlier crucial periods in development. The process of synaptic pruning has by puberty eliminated some 40% of the synapses, leading to the disappearance of glutematergic excitatory synapses without apparently appreciably influencing inhibitory GABAergic neurons. As a consequence, early maturation is related to the manic-depressive syndrome and characterized by increased neural excitability. Conversely, late maturation is related to schizophrenia characterized by diminished neural activity. Saugstad demonstrates using cross-national and neuroscience studies the multifactoral and environmental influences on rates of maturation and thereby mental illness. Using these data Saugstad reasons her agreement with the Kraepelinian dichotomy based on the existence of two extremes in brain structure and function developed through interactions between the person and the environment.
Topics: Bipolar Disorder; Brain; Humans; Multifactorial Inheritance; Psychosexual Development; Puberty; Puberty, Delayed; Schizophrenia; Sexual Maturation
PubMed: 18516513
DOI: 10.1007/s00406-008-2005-2 -
Scandinavian Journal of Medicine &... Feb 2009
Topics: Ethics, Research; Ethnicity; Humans; Sexual Maturation; Sports Medicine
PubMed: 19175762
DOI: 10.1111/j.1600-0838.2009.00910.x -
Journal of Research on Adolescence :... Mar 2019The measurement of puberty is an intricate and precise task, requiring a match between participants' developmental age and appropriate techniques to identify and capture... (Review)
Review
The measurement of puberty is an intricate and precise task, requiring a match between participants' developmental age and appropriate techniques to identify and capture variations in maturation. Much of the foundational work on puberty and its psychosocial correlates was conducted several decades ago. In this article, we review the biological foundation of puberty; the operationalization of puberty in statistical analyses; and strategies for considering diversity and social context in research to help researchers align measurement with meaningful conceptual questions. These three areas are particularly important, given new statistical techniques, greater awareness of individual variations in development, and key differences between past cohorts and youth coming of age today.
Topics: Adolescent; Adolescent Development; Adolescent Health; Epigenesis, Genetic; Female; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Gene-Environment Interaction; Humans; Male; Models, Biological; Puberty; Research Design; Sexual Maturation; Social Environment
PubMed: 30869839
DOI: 10.1111/jora.12371 -
Endocrinology Oct 1993Neuropeptide Y (NPY) is known to be involved in the central regulation of appetite, sexual behavior and reproductive function. Whereas central administration of NPY...
Neuropeptide Y (NPY) is known to be involved in the central regulation of appetite, sexual behavior and reproductive function. Whereas central administration of NPY strongly stimulates feeding, diet restriction produces overexpression of NPY in the arcuate and paraventricular nuclei that might reflect behavioral adaptations to shortage of food. The role of NPY for the regulation of sexual function is still controversial. Whereas NPY is stimulatory during proestrus in the rat, acute administration of NPY is inhibitory in castrated animals and we have shown that chronic administration of NPY inhibits both the gonadotropic and somatotropic axis in adult female rats. In order to further analyse the role of NPY during sexual maturation, a model of delayed sexual maturation imposed by food restriction and return to ad-libitum feeding was used. Young female rats were restricted to 7-8 g food daily starting at 24 days of life (d). This restriction completely prevented sexual maturation. At 50 d, ICV cannulas were placed and at 60 d, Alzet minipumps either delivering NPY (18 micrograms/day) or vehicle into the ICV cannula were implanted dorsally. At 61 d, rats were switched to ad-libitum feeding, a change that produced vaginal opening within 4 days in all vehicle-treated rats. In the rats receiving NPY, significantly increased food intake and weight gain were observed but only one out of the 9 rats studied experienced vaginal opening at 66 d, the other 8 animals remaining sexually immature at 67 d at sacrifice. Sexual immaturity of NPY-treated rats was further confirmed by decreased ovarian weight and reduced number of pituitary GnRH receptors. Plasma IGF-I levels were markedly reduced in NPY-treated rats. Since food restriction has been shown both to increase hypothalamic NPY and to reduce or inhibit sexual function, these data bring evidence for the first time that NPY could be involved in the inhibition of sexual maturation imposed by food restriction, since maintenance of elevated NPY levels in the hypothalamus did prolong this state of sexual immaturity despite restoration of normal food intake.
Topics: Animals; Eating; Female; Food Deprivation; Insulin-Like Growth Factor I; Neuropeptide Y; Neurosecretory Systems; Rats; Rats, Sprague-Dawley; Sexual Maturation
PubMed: 8404631
DOI: 10.1210/endo.133.4.8404631 -
Brain Research Dec 2010The initiation of mammalian puberty requires a sustained increase in pulsatile release of gonadotrophin releasing hormone (GnRH) from the hypothalamus. This increase is... (Review)
Review
The initiation of mammalian puberty requires a sustained increase in pulsatile release of gonadotrophin releasing hormone (GnRH) from the hypothalamus. This increase is brought about by coordinated changes in transsynaptic and glial-neuronal communication, consisting of an increase in neuronal and glial stimulatory inputs to the GnRH neuronal network and the loss of transsynaptic inhibitory influences. GnRH secretion is stimulated by transsynaptic inputs provided by excitatory amino acids (glutamate) and at least one peptide (kisspeptin), and by glial inputs provided by growth factors and small bioactive molecules. The inhibitory input to GnRH neurons is mostly transsynaptic and provided by GABAergic and opiatergic neurons; however, GABA has also been shown to directly excite GnRH neurons. There are many genes involved in the control of these cellular networks, and hence in the control of the pubertal process as a whole. Our laboratory has proposed the concept that these genes are arranged in overlapping networks internally organized in a hierarchical fashion. According to this concept, the highest level of intra-network control is provided by transcriptional regulators that, by directing expression of key subordinate genes, impose genetic coordination to the neuronal and glial subsets involved in initiating the pubertal process. More recently, we have begun to explore the concept that a more dynamic and encompassing level of integrative coordination is provided by epigenetic mechanisms.
Topics: Animals; Epigenomics; Female; Humans; Neurosecretory Systems; Puberty; Sexual Maturation; Transcription, Genetic
PubMed: 20851111
DOI: 10.1016/j.brainres.2010.09.039