Timing of puberty and synchronization of seasonal rhythms by simulated natural photoperiods in female Siberian hamsters

2007 ◽  
Vol 293 (1) ◽  
pp. R413-R420 ◽  
Author(s):  
Matthew P. Butler ◽  
Justin J. Trumbull ◽  
Kevin W. Turner ◽  
Irving Zucker
Keyword(s):  
Pubertal Development ◽  
Somatic Growth ◽  
Life History Trait ◽  
Delayed Puberty ◽  
Summer Solstice ◽  
Early Puberty ◽  
Seasonal Rhythms ◽  
Siberian Hamsters ◽  
Natural Photoperiod ◽  
Timing Of Puberty

The timing of puberty is a critical life history trait of short-lived species; spring-born individuals mature rapidly and breed in the season of birth, whereas young born in mid- to late summer delay puberty until the next spring. The cues that govern the transition from rapid to delayed maturation in natural populations remain unknown. To identify ecologically relevant photoperiod cues that control timing of puberty, we monitored nine cohorts of female Siberian hamsters ( Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). Hamsters born by the summer solstice underwent rapid somatic growth and achieved puberty that summer; among females born 2–4 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born 6 or more weeks after the solstice generally delayed puberty until the following spring. The transition from accelerated to delayed pubertal development in the SNP occurred at day lengths that induce early puberty when presented as static photoperiods. Despite differences in timing of birth and timing of puberty, fall and subsequent spring seasonal events occurred at similar calendar dates in all cohorts. We found no evidence that prenatal photoperiod history influenced postnatal development of female hamsters. Considered together with a parallel study on males, the present findings point to sex differences in responsiveness to natural photoperiod variations. In both sexes, incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms.

Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters

2007 ◽  
Vol 293 (1) ◽  
pp. R402-R412 ◽  
Author(s):  
Matthew P. Butler ◽  
Kevin W. Turner ◽  
Jin Ho Park ◽  
James P. Butler ◽  
Justin J. Trumbull ◽  
...  
Keyword(s):  
Somatic Growth ◽  
Day Length ◽  
Delayed Puberty ◽  
Testicular Development ◽  
Early Puberty ◽  
Seasonal Rhythms ◽  
Siberian Hamsters ◽  
Natural Photoperiod ◽  
Timing Of Puberty ◽  
Short Days

Photoperiodism research has relied on static day lengths and abrupt transitions between long and short days to characterize the signals that drive seasonal rhythms. To identify ecologically relevant critical day lengths and to test the extent to which naturally changing day lengths synchronize important developmental events, we monitored nine cohorts of male Siberian hamsters ( Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). SNP hamsters born from 4 wk before to 2 wk after the solstice underwent rapid somatic and gonadal growth; among those born 4–6 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born eight or more weeks after the solstice failed to undergo early testicular development. The transition to delayed development occurred at long day lengths, which induce early puberty when presented as static photoperiods. The first animals to delay puberty may do so predominantly on the basis of postnatal decreases in day length, whereas in later cohorts, a comparison of postnatal day length to gestational day length may contribute to arrested development. Despite differences in timing of birth and timing of puberty, autumn gonadal regression and spring gonadal and somatic growth occurred at similar calendar dates in all cohorts. Incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms by providing hamsters with a richer source of environmental timing cues than are available in simple static day lengths.

scholarly journals The Posterodorsal Medial Amygdala Regulates the Timing of Puberty Onset in Female Rats

Endocrinology ◽  
2015 ◽  
Vol 156 (10) ◽  
pp. 3725-3736 ◽  
Author(s):  
X. F. Li ◽  
M. H. Hu ◽  
B. P. Hanley ◽  
Y. S. Lin ◽  
L. Poston ◽  
...  
Keyword(s):  
Body Weight ◽  
Brain Region ◽  
Female Rats ◽  
Delayed Puberty ◽  
Calorie Intake ◽  
Medial Amygdala ◽  
Early Puberty ◽  
Receptor Antagonism ◽  
Play Fighting ◽  
Timing Of Puberty

Obesity is the major risk factor for early puberty, but emerging evidence indicates other factors including psychosocial stress. One key brain region notable for its role in controlling calorie intake, stress, and behavior is the amygdala. Early studies involving amygdala lesions that included the medial nucleus advanced puberty in rats. More recently it was shown that a critical site for lesion-induced hyperphagia and obesity is the posterodorsal subnucleus of the medial amygdala (MePD), which may explain the advancement of puberty. Glutamatergic activity also increases in the MePD during puberty without a corresponding γ-aminobutyric acid (GABA)ergic change, suggesting an overall activation of this brain region. In the present study, we report that neurotoxic lesioning of the MePD advances puberty and increases weight gain in female rats fed a normal diet. However, MePD lesioned rats fed a 25% nonnutritive bulk diet also showed the dramatic advancement of puberty but without the increase in body weight. In both dietary groups, MePD lesions resulted in an increase in socialization and a decrease in play fighting behavior. Chronic GABAA receptor antagonism in the MePD from postnatal day 21 for 14 days also advanced puberty, increased socialization, and decreased play fighting without altering body weight, whereas glutamate receptor antagonism delayed puberty and decreased socialization without affecting play fighting. In conclusion, our results suggest the MePD regulates the timing of puberty via a novel mechanism independent of change in body weight and caloric intake. MePD glutamatergic systems advance the timing of puberty whereas local GABAergic activation results in a delay.

scholarly journals SUN-594 Pubertal Timing and Hormonal Correlates in Male Obesity

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Jean De Schepper ◽  
Evy Berlanger ◽  
Monique Van Helvoirt ◽  
Ann De Guchtenaere ◽  
Eddy Basslé ◽  
...  
Keyword(s):  
Pubertal Timing ◽  
Pubertal Development ◽  
Age Distribution ◽  
Delayed Puberty ◽  
Low Grade ◽  
Z Score ◽  
Early Puberty ◽  
Pubertal Onset ◽  
Genital Development ◽  
Low Grade Inflammation

Abstract An early, normal or delayed pubertal onset have been described in overweight/ obese males(1). A greater prepubertal adiposity has been associated with a greater risk for delayed puberty in males, but an underlying mechanism was not explored(2). We investigated whether an increased testosterone aromatization or an higher degree of low-grade inflammation might be more prevalent in obese males with a delay in genital development. Pubertal status assessment by Tanner staging and measurement of morning serum testosterone, estradiol, leptin, and hSCRP by standard laboratory methods were performed in 191 male adolescents, aged between 10 and 18.6 yr (median 12.8 yr) with overweight (BMI z-score > 1.3), starting an ambulatory (n = 138) or a residential weight loss program (n = 55). Their median (range) BMI z-score was 2.32 (1.34 – 3.38). Delayed / slow and early / rapid genital development was defined by a Tanner genital stage respectively above the 90th or below 10th percentile age distribution (national Flemish standards of 2004). In 3 males pubertal development was advanced, while in 34 it was delayed. In the remaining 154 adolescents genital stage was normally timed. Males with a delayed timing or progression of genital development were older (median(range) age:14.8 (11.6-18.6) yr vs 12.3 (10-18.6) yr; p< 0.005) and shorter (height sds: -0.55 (-1.90- 1.48) vs 0.49 (-3 – 3.19); p < 0.005), and had a higher birthweight (birthweight z-score: 0.15(-3.51-2.75) vs -0.34(-4.7-3.30); p = 0.058), but a similar BMI and waist z-score in comparison with males with a normally timed puberty. Median serum estradiol, leptin, and hSCRP concentrations did not differ significantly between those with a normal or a delayed pubertal onset or progression. In conclusion, pubertal delay is more frequently observed than early puberty in males referred to obesity clinics. Neither low grade inflammation nor increased estradiol production appear to be associated with a later onset of slower progression of genital development in male obesity. References (1) Li W et al. Int J Environ Res Public Health. 2017 Oct 24;14(10) (2) Lee JM et al. Arch Pediatr Adolesc Med. 2010 Feb;164(2):139-44.

scholarly journals Etiology of Increased Referrals for Evaluation of Early Puberty in a Tertiary Care Center in Turkey: True Precocious Puberty, Obesity, or Parental Anxiety and Lack of Knowledge?

2021 ◽  
Vol 8 ◽  
pp. 2333794X2110090
Author(s):  
Ayse Pinar Cemeroglu ◽  
Damlanur Kaval ◽  
Ozan Ozcan
Keyword(s):  
Precocious Puberty ◽  
Care Center ◽  
Pubertal Development ◽  
Tertiary Care ◽  
Parental Anxiety ◽  
Adrenal Hyperplasia ◽  
Pediatric Endocrinology ◽  
Early Puberty ◽  
Classic Congenital Adrenal Hyperplasia ◽  
Timing Of Puberty

There has been a global increase in pediatric endocrinology referrals for the concerns of early puberty. The objective of this study was to determine the reasons behind this increase. A retrospective cross-sectional study was designed to analyze the clinical characteristics of patients seen for the concerns of early puberty in pediatric endocrinology clinic of a tertiary care center (Study A). Additionally, a prospective questionnaire study was designed to assess the knowledge and concerns of the mothers regarding the timing of puberty in girls (Study B). In study A, of the 305 girls, 42.9% were overweight/obese, 68.5% either had normal pubertal development for age or were prepubertal, 1 had non-classic congenital adrenal hyperplasia, and 2 had central precocious puberty. Of the 36 boys, 56% were overweight/obese, 64% either had normal pubertal development for age or were prepubertal, and 1 had non-classic congenital adrenal hyperplasia. In study B, 95% of the participants thought the girls have been developing earlier, over 10% considered the first sign of puberty to be normal after the age 14 years and 12.4% considered menarche to be normal after age 14 years. The common sources of anxiety for the participants regarding the earlier timing of puberty were psychosocial issues and short final height. In conclusion, many parents had wrong beliefs/information about the normal timing of puberty and were concerned about precocious puberty in girls. Education of parents about the normal timing of puberty may help avoiding unnecessary referrals, parental anxiety, and financial burden to the society.

scholarly journals Genomic analyses for age at menarche identify 389 independent signals and indicate BMI-independent effects of puberty timing on cancer susceptibility

2016 ◽  
Author(s):  
Felix R. Day ◽  
Deborah J. Thompson ◽  
Hannes Helgason ◽  
Daniel I. Chasman ◽  
Hilary Finucane ◽  
...  
Keyword(s):  
Rare Variants ◽  
Cancer Susceptibility ◽  
Pubertal Development ◽  
Genetic Regulation ◽  
Age At Menarche ◽  
Cancer Risks ◽  
Early Puberty ◽  
Opposite Pattern ◽  
Timing Of Puberty ◽  
Independent Effects

AbstractThe timing of puberty is a highly polygenic childhood trait that is epidemiologically associated with various adult diseases. Here, we analyse 1000-Genome reference panel imputed genotype data on up to ~370,000 women and identify 389 independent signals (all P<5×10−8) for age at menarche, a notable milestone in female pubertal development. In Icelandic data from deCODE, these signals explain ~7.4% of the population variance in age at menarche, corresponding to one quarter of the estimated heritability. We implicate over 250 genes via coding variation or associated gene expression, and demonstrate enrichment across genes active in neural tissues. We identify multiple rare variants near the imprinted genes MKRN3 and DLK1 that exhibit large effects on menarche only when paternally inherited. Disproportionate effects of variants on early or late puberty timing are observed: single variant and heritability estimates are larger for early than late puberty timing in females. The opposite pattern is seen in males, with larger estimates for late than early puberty timing. Mendelian randomization analyses indicate causal inverse associations, independent of BMI, between puberty timing and risks for breast and endometrial cancers in women, and prostate cancer in men. In aggregate, our findings reveal new complexity in the genetic regulation of puberty timing and support new causal links with adult cancer risks.

Photoperiod synchronizes reproduction and growth in the southern flying squirrel,Glaucomys volans

1990 ◽  
Vol 68 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Theresa M. Lee ◽  
Irving Zucker
Keyword(s):  
Body Weight ◽  
Reproductive Condition ◽  
Glaucomys Volans ◽  
Flying Squirrel ◽  
Seasonal Rhythms ◽  
Flying Squirrels ◽  
Body Weights ◽  
Natural Photoperiod ◽  
Ad Libitum ◽  
Southern Flying Squirrel

Southern flying squirrels were housed in a simulated natural photoperiod for 40°N latitude and held at a constant temperature of 23 °C with food and water provided ad libitum. Body weight and reproductive condition were monitored weekly for 2 years. Males were in reproductive condition between January and mid-August and females were in estrus from late February to mid-April and again from mid-June until early August. Young were conceived during both estrous periods and several squirrels produced two litters in the same year. Minimum body weights were recorded in adults in mid-October each year. Pups born in the spring grew more rapidly than those from summer litters, and reached puberty at 2.5 months as compared with 6–8 months of age for the summer litters. Several seasonal rhythms appear to be controlled by photoperiod in this species.

scholarly journals The human chorionic gonadotropin test is more powerful than the gonadotropin-releasing hormone agonist test to discriminate male isolated hypogonadotropic hypogonadism from constitutional delayed puberty

2003 ◽  
pp. 23-29 ◽  
Author(s):  
V Degros ◽  
C Cortet-Rudelli ◽  
B Soudan ◽  
D Dewailly
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Testosterone Level ◽  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Serum Testosterone ◽  
Serum Testosterone Level ◽  
Delayed Puberty ◽  
Hcg Test

OBJECTIVE: The effectiveness of biological investigations aiming at discriminating isolated hypogonadotropic hypogonadism (IHH) from constitutional delayed puberty (CDP) in male patients is still controversial. We revisited the diagnostic power of the basal serum testosterone level, the Triptorelin test and the human chorionic gonadotropin (hCG) test in a cohort of 33 boys with delayed puberty. DESIGN: Boys were aged 14.2 to 26.2 Years at referral. A 5-Year-long clinical follow-up after the initial study allowed confirmation of the diagnosis. At the end of the follow-up period, IHH was found in 13 patients while the other 20 had normal spontaneous pubertal development (CDP). RESULTS: At referral, a basal morning testosterone level >1.7 nmol/l was observed in 55% of patients with CDP exclusively (predictive positive value (PPV)=100%; predictive negative value (PNV)=59%). For CDP, the PPV of the LH peak 3 h after Triptorelin was 100% by setting the upper threshold at 14 IU/l and the PNV was 72%. However, no lower threshold could discriminate IHH from CDP in the remaining patients with an LH peak 3 h after Triptorelin <14 IU/l. In CDP patients, the PPV of the serum testosterone increment after hCG stimulation (deltaT/hCG) was 100% for values >9 nmol/l (PNV=72%). In IHH patients, the PPV of deltaT/hCG was 100% for values <3 nmol/l (PNV=82%). Only 29% of the studied population had a deltaT/hCG between these lower and upper thresholds and therefore could not have been classified initially. CONCLUSIONS: (i) Dynamic testing for the diagnosis of delayed puberty is useful only when the basal testosterone level is lower than 1.7 nmol/l; (ii) in that case, the hCG test has better discriminating power than the Triptorelin test and appears as the best cost-effective investigation. It prevents useless and expensive investigations in about one-half of CDP patients with a basal morning testosterone level lower than 1.7 nmol/l.

scholarly journals Heritability of Testosterone Levels in 12-Year-Old Twins and Its Relation to Pubertal Development

2006 ◽  
Vol 9 (4) ◽  
pp. 558-565 ◽  
Author(s):  
Rosa A. Hoekstra ◽  
Meike Bartels ◽  
Dorret I. Boomsma
Keyword(s):  
Pubertal Development ◽  
Environmental Influences ◽  
Pubic Hair ◽  
Self Report ◽  
Early Puberty ◽  
Salivary Testosterone ◽  
Testosterone Levels ◽  
Genital Development ◽  
Opposite Sex ◽  
Hair Development

AbstractThe aim of this study was to estimate the heritability of variation in testosterone levels in 12-year-old children, and to explore the overlap in genetic and environmental influences on circulating testosterone levels and androgen-dependent pubertal development. Midday salivary testosterone samples were collected on 2 consecutive days in a sample of 183 unselected twin pairs. Androgen-induced pubertal development was assessed using self-report Tanner scales of pubic hair development (boys and girls) and genital development (boys). A significant contribution of genetic effects to the variance in testosterone levels was found. Heritability was approximately 50% in both boys and girls. The remaining proportion of the variance in testosterone levels could be explained by nonshared environmental influences. The relatively high correlation between testosterone levels of opposite-sex dizygotic twins suggests that sex differences in genes influencing variation in testosterone levels have not yet developed in preand early puberty. Variance in pubertal development was explained by a large genetic component, moderate shared environmental influences, and a small nonshared environmental effect. Testosterone levels correlated moderately (r = .31) with pubertal development; the covariance between testosterone levels and pubertal development was entirely accounted for by genetic influences.

Perinatal photoperiod organizes adult immune responses in Siberian hamsters (Phodopus sungorus)

2006 ◽  
Vol 290 (6) ◽  
pp. R1714-R1719 ◽  
Author(s):  
Zachary M. Weil ◽  
Leah M. Pyter ◽  
Lynn B. Martin ◽  
Randy J. Nelson
Keyword(s):  
Immune System ◽  
Immune Function ◽  
Breeding Season ◽  
Somatic Growth ◽  
Developmental Trajectory ◽  
Day Length ◽  
Phodopus Sungorus ◽  
Siberian Hamsters ◽  
Time Of Year ◽  
Induced Changes

Individuals of many nontropical rodent species display reproductive, immunological, and somatic responses to day length. In general, short day (SD) lengths inhibit reproduction and enhance immune function in the laboratory when all other conditions are held constant. Most studies to date have focused on seasonal variation in immune function in adulthood. However, perinatal photoperiods also communicate critical day length information and serve to establish a developmental trajectory appropriate for the time of year. Nontropical rodents born early in the breeding season undergo rapid reproductive development, presumably to promote mating success during their first reproductive season. Rodents born late in the breeding season suspend somatic growth and puberty until the following vernal breeding season. We tested the hypothesis that perinatal day lengths have similar enduring effects on the immune system of rodents. Siberian hamsters ( Phodopus sungorus) were maintained prenatally and until weaning (21 days) in either SDs (8 h light:16 h dark) or long days (LD) (16 h light:8 h dark), then they were weaned into either the opposite photoperiod or maintained in their natal photoperiod, forming four groups (LD-LD, LD-SD, SD-LD, and SD-SD). After 8-wk in these conditions, cell-mediated immune activity was compared among groups. SD-SD hamsters of both sexes enhanced immune function relative to all other groups. The reproductive effects of perinatal photoperiod were not evident by the end of the experiment; circulating testosterone and cortisol sampled at the end of the experiment reflected the postweaning, but not the perinatal photoperiod. This experiment demonstrates long-lasting organizational effects of perinatal photoperiod on the rodent immune system and indicates that photoperiod-induced changes in the immune system are dissociable from changes in the reproductive system.

Precocious Puberty

2006 ◽  
Vol 00 (02) ◽  
Author(s):  
Paul B Kaplowitz
Keyword(s):  
Precocious Puberty ◽  
Linear Growth ◽  
Pubertal Development ◽  
Black Girls ◽  
Pubic Hair ◽  
Growth Spurt ◽  
Tall Stature ◽  
Early Puberty ◽  
Bone Maturation ◽  
Early Appearance

Precocious puberty refers to the appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal.Although traditionally, any signs of puberty in girls prior to age eight years have been considered abnormal, recent studies indicate that signs of early puberty (breasts and pubic hair) are often present in girls (particularly black girls) between ages 6–8 years.The early growth spurt initially can cause tall stature, but rapid bone maturation can cause linear growth to cease too early and result in short adult stature.The early appearance of breasts or menses in girls and increased libido in boys can cause emotional distress for some children.

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