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Reproductive Biology Mar 2010This review is designed to describe some pituitary mechanisms indispensable for growth and sexual maturation during the neuroendocrine adaptation of the female mammal to... (Review)
Review
This review is designed to describe some pituitary mechanisms indispensable for growth and sexual maturation during the neuroendocrine adaptation of the female mammal to the extrauterine environment. We define the phases of postnatal development on the basis of secretory patterns of hormones. The infantile period is characterized by accelerated growth, and elevated secretion of growth hormone (GH) and follicle-stimulating hormone (FSH) in contrast to the diminished secretion of luteinizing hormone (LH). The transition from infancy to prepuberty generates the attenuation of somatic growth in non-primate mammals and the beginning of sexual maturation. The mechanisms of this transition involve the effects of weaning, which is associated with a rupture of the young-mother bond and, if abrupt, results in the stress of maternal deprivation. Maternal deprivation involves the stress-like endocrine response of pituitary and influences the mechanisms underlying the secretion of GH and FSH. An acute decrease in the secretion of GH and FSH at the initiation of prepuberty and an increase in the storage and pulsatile release of LH according to progressive prepubertal stages are pituitary endocrine features of post-infantile maturation. There are two factors important for timing of puberty, the maturity of gonadotroph population manifested by the adequate size of LH-containing cell subpopulation and the circumstances of an external environment optimal for reproductive functions in adults. Thus, the intrapituitary endocrine mechanisms of maturation have a psychosomatic nature during weaning and histomorphological nature during the postinfantile transition to puberty. In seasonal breeders, the endocrine timing of puberty has a circumannual seasonal nature.
Topics: Animals; Endocrine System; Mammals; Maternal Deprivation; Photoperiod; Pituitary Gland; Sexual Maturation; Stress, Physiological
PubMed: 20349020
DOI: 10.1016/s1642-431x(12)60034-5 -
Biological Reviews of the Cambridge... May 2012Delayed plumage maturation is the delayed acquisition of a definitive colour and pattern of plumage until after the first potential breeding period in birds. Here we... (Review)
Review
Delayed plumage maturation is the delayed acquisition of a definitive colour and pattern of plumage until after the first potential breeding period in birds. Here we provide a comprehensive overview of the numerous studies of delayed plumage maturation and a revised theoretical framework for understanding the function of delayed plumage maturation in all birds. We first distinguish between hypotheses that delayed plumage maturation is attributable to a moult constraint with no adaptive function and hypotheses that propose that delayed plumage maturation is a component of an adaptive life-history strategy associated with delayed reproductive investment. We then recognize three potential benefits of delayed plumage maturation: crypsis, mimicry and status signaling. Evidence suggests that delayed plumage maturation is not a consequence of developmental constraints and instead represents a strategy to maximize reproductive success in circumstances where young adults cannot effectively compete with older adults for limited resources, particularly breeding opportunities. A multi-factorial explanation that takes into account lifespan and the degree of competition for limited breeding resources and that combines the benefits of an inconspicuous appearance with the benefits of honest signaling of reduced competitiveness provides a general explanation for the function of delayed plumage maturation in most bird species. Delayed plumage maturation should be viewed as a component of alternative reproductive strategies that can include delay in both plumage and sexual development. Such strategies are frequently facultative, with individuals breeding prior to the acquisition of definitive plumages when conditions are favourable. Presumably, the benefits of delayed plumage maturation ultimately enhance lifetime reproductive success, and studying delayed plumage maturation within the context of lifetime reproductive success should be a goal of future studies.
Topics: Animals; Behavior, Animal; Birds; Feathers; Sexual Maturation; Social Behavior
PubMed: 21790949
DOI: 10.1111/j.1469-185X.2011.00193.x -
The Journals of Gerontology. Series A,... Jul 2015We previously reported that insulin-like growth factor 1 (IGF1) was involved in coregulating female sexual maturation and longevity. To understand the underlying genetic...
We previously reported that insulin-like growth factor 1 (IGF1) was involved in coregulating female sexual maturation and longevity. To understand the underlying genetic mechanisms, based on the strain survey assays of development and aging traits, we crossed two mouse strains, KK/HIJ and PL/J, and produced 307 female F2 mice. We observed the age of vaginal patency (AVP) and the life span of these females. We also measured circulating IGF1 level at 7, 16, 24, 52, and 76 weeks. IGF1 level at 7 weeks significantly correlated with AVP. IGF1 levels at ages of 52 and 76 weeks negatively correlated with longevity (p ≤ .05). A gene mapping study found 22, 4 ,and 3 quantitative trait loci for IGF1, AVP, and life span, respectively. Importantly, the colocalization of IGF1, AVP, and life span quantitative trait loci in the distal region of chromosome 2 suggests this locus carries gene(s) that could regulate IGF1, AVP, and life span. In this region, proprotein convertase subtilisin/kexin type 2 has been found to be associated with female sexual maturation in a human genome-wide association study. We verified the roles of proprotein convertase subtilisin/kexin type 2 in regulating IGF1 and AVP by showing that depletion of proprotein convertase subtilisin/kexin type 2 significantly reduced IGF1 and delayed AVP in mice, suggesting that it also might be involved in the regulation of aging.
Topics: Animals; Chromosome Mapping; Female; Insulin-Like Growth Factor I; Lod Score; Longevity; Mice; Mice, Inbred Strains; Proprotein Convertase 2; Quantitative Trait Loci; Sexual Maturation
PubMed: 25070661
DOI: 10.1093/gerona/glu114 -
Economics and Human Biology Mar 2013The aim of this study was to determine secular changes in the sexual maturation of children and adolescents from Eastern regions of Poland between 1980 and 2000, with... (Comparative Study)
Comparative Study
The aim of this study was to determine secular changes in the sexual maturation of children and adolescents from Eastern regions of Poland between 1980 and 2000, with special attention paid to rural-urban differences. Our sample comprised 34,055 girls and 28,100 boys from 9 to 18 years of age. The age at which each gender reached each stage of sexual maturation was examined, along with menarcheal age in girls. An increase in the rate of sexual maturation was observed over the 20-year period of this study. Menarcheal age in girls decreased by 0.59 years. The length of sexual maturation decreased: from 6.58 years to 3.85 years in girls and from 5.84 years to 3.65 years in boys. A significantly faster rate of sexual maturation was observed between 1990 and 2000. Over the entire 20-year period, adolescents living in rural settings experienced a slower rate of sexual maturation than did their urban peers.
Topics: Adolescent; Child; Female; Humans; Male; Models, Statistical; Poland; Rural Population; Sexual Maturation; Surveys and Questionnaires; Urban Population
PubMed: 21354869
DOI: 10.1016/j.ehb.2011.01.002 -
Endocrinology Dec 1984Previous studies from our laboratory demonstrated that daily afternoon melatonin injections from 20-40 days of age inhibited sexual development of young male rats,...
Previous studies from our laboratory demonstrated that daily afternoon melatonin injections from 20-40 days of age inhibited sexual development of young male rats, whereas in adult animals, similar injections had no effect. The present study was designed to determine more precisely the critical age period during which melatonin exerts its inhibiting effect and to see whether spontaneous sexual maturation resumes after discontinuation of melatonin administration at 45 days of age or even during continuous administration of melatonin until 115 days of age. Sexual maturation was evaluated using weights of seminal vesicles and testes; plasma levels of testosterone, FSH, and LH; pituitary contents and concentrations of FSH and LH; and, finally, pituitary content of GnRH receptors. Administration of melatonin to young male rats from 20-30 days of life had the same inhibitory effect on sexual maturation at 40 days as melatonin injections from 20-40 days. In contrast, administration of melatonin from 30-40 days only slightly decreased plasma testosterone concentration, weight of seminal vesicles, and pituitary GnRH receptor content. Melatonin administration from 38-40 days had no effect. Daily melatonin administration from 20-45 days of age was followed by resumption of sexual maturation, as observed at 70 days. The recovery was complete by 80 days of age when all of the parameters studied reflected complete sexual maturation. Finally, in rats treated continuously with melatonin from days 20 until 115, sexual maturation occurred but was delayed by about 20-30 days. Beginning of sexual development was observed at 60 days of life, and full development was attained only at 100 days. These data confirm that melatonin delays sexual maturation in the young male rat when administered daily in the afternoon. They demonstrate that this inhibitory action of melatonin is most critical between 20 and 30 days of life and is reversible regardless of whether melatonin administration is discontinued after 45 days of life. The suppression of the pubertal peaks of pituitary GnRH receptor number and pituitary and plasma FSH concentrations in treated rats suggests that melatonin interferes with the pubertal increase in GnRH secretion. In conclusion, these reversible effects of melatonin suggest that this pineal indolamine represents an important factor for the timing of sexual maturation.
Topics: Aging; Animals; Circadian Rhythm; Drug Administration Schedule; Male; Melatonin; Rats; Rats, Inbred Strains; Sexual Maturation
PubMed: 6499770
DOI: 10.1210/endo-115-6-2303 -
Biology of Reproduction Dec 1989Effects of short-day photoperiod, pinealectomy, and melatonin on sexual maturation were tested in Peromyscus leucopus from either Connecticut (CT) or Georgia (GA).... (Comparative Study)
Comparative Study
Effects of short-day photoperiod, pinealectomy, and melatonin on sexual maturation were tested in Peromyscus leucopus from either Connecticut (CT) or Georgia (GA). Laboratory reared-stocks from CT and GA were exposed to short daylength (photoperiod) from birth or 25 days of age. At 12 wk of age, delay in sexual maturation was indicated in most CT mice by decreased testis length, combined testes weight, and seminal vesicle weight. Conversely, GA animals did not delay sexual maturation when exposed to short-day photoperiod from either birth or 25 days of age. These results indicate that responses to short daylengths differ for juvenile CT and GA populations. In a second experiment, pinealectomized or sham-operated CT males were exposed to short-day (9L:15D) or long-day (16L:8D) photoperiod from birth. Pinealectomy blocked the effect of short daylength on reproduction. Therefore, the pineal must be involved in the delay of sexual maturation observed for short-day CT mice. The effects of melatonin, a pineal gland hormone, were tested with chronic s.c. implants or daily injections. In CT mice given either melatonin implants or afternoon injections, sexual maturation was delayed. GA mice were insensitive to all melatonin treatments. Further, no differences in circadian organization (phase angle, duration of activity, period under constant dark) between GA and CT animals were apparent. Collectively, these studies indicate that melatonin is involved in the mechanism responsible for delay of sexual maturation in CT mice. Short-day insensitivity of GA Peromyscus leucopus probably results from a deficiency in the melatonin effector pathway and is not due to a disruption of circadian organization.
Topics: Animals; Body Weight; Connecticut; Georgia; Light; Male; Melatonin; Organ Size; Periodicity; Peromyscus; Pineal Gland; Sexual Maturation; Testis
PubMed: 2624861
DOI: 10.1095/biolreprod41.6.1004 -
Behavioural Processes Jun 2020Nutritional stress during the earliest stages of an animal's life can have long-term effects on its behavior and reproductive performance, but the effects of brief...
Nutritional stress during the earliest stages of an animal's life can have long-term effects on its behavior and reproductive performance, but the effects of brief periods of nutritional stress later in life are less well-studied. We manipulated female diet in Narnia femorata (Hemiptera: Coreidae) and investigated to what extent nutritional stress during sexual maturation affects subsequent sexual behavior and long-term offspring production. We show that nutritional stress at this key point during early adulthood can have lasting effects on reproduction, impairing long-term offspring production despite the subsequent return of good nutrition. These results demonstrate that nutritional availability during late stages of development, in young adults, can be crucial to future fitness. We found no effect of temporary nutritional stress on female receptivity to mating or attractiveness to males; although females that were less receptive also produced fewer offspring in the next month. Overall, we demonstrate that even brief periods of nutritional deprivation late in development can have drastic long-term effects, apparently beyond compensation, and despite a good early nutritional environment.
Topics: Animal Nutritional Physiological Phenomena; Animals; Female; Hemiptera; Reproduction; Sexual Behavior, Animal; Sexual Maturation; Stress, Physiological
PubMed: 32259623
DOI: 10.1016/j.beproc.2020.104122 -
Medecine Sciences : M/S May 2022
Topics: Fertility; Gonadotropin-Releasing Hormone; Humans; Neuroglia; Neurons; Sexual Maturation
PubMed: 35608464
DOI: 10.1051/medsci/2022047 -
Journal of the Association of Pediatric... 1988
Review
Topics: Antineoplastic Agents; Child; Female; Growth Disorders; Humans; Male; Neoplasms; Radiotherapy; Reference Values; Sexual Maturation
PubMed: 3060591
DOI: 10.1177/104345428800500405 -
Journal of Medical Ethics May 2024Räsänen draws a distinction between chronological age and biological age and argues that biological ageing is (sometimes) desirable. To demonstrate this, he asks us to...
Räsänen draws a distinction between chronological age and biological age and argues that biological ageing is (sometimes) desirable. To demonstrate this, he asks us to consider the case of April, who like Karel Čapek's Elina Makropulos, has stopped biologically ageing. Unlike Makropulos, though, April's biological ageing was halted before puberty, so she will never mature into adulthood. Räsänen contends this case shows ageing can be desirable, but this equivocates between maturing and ageing. Here I argue biological ageing, or the wear and tear normally associated with chronological ageing, is undesirable, but that maturing can be desirable.
Topics: Humans; Aging; Female; Sexual Maturation
PubMed: 37553223
DOI: 10.1136/jme-2023-109418