Age Of Puberty Onset Research Articles

Maternal diet-induced obesity in swine with leptin resistance modifies puberty and pregnancy outputs of the adult offspring.

The assessment of reproductive features (puberty, fertility and prolificacy) in female Iberian pigs indicates that exposition to intrauterine maternal malnutrition, either by deficiency or excess, is associated with juvenile obesity and a significantly earlier age of puberty onset. At adulthood, prenatal exposition to undernutrition affects reproductive outputs by diminishing prolificacy, an effect that was not found in females exposed to prenatal overnutrition.

Relationships between age of puberty onset and height at age 18 years in girls and boys

Changes during puberty may influence final adult height. Height is related to multiple health conditions, including lung function. We investigated the association between the age of onset of five puberty events and height at age 18 years, analyzing boys and girls separately. Of 1456 children recruited into the Isle of Wight birth cohort (1989-1990), 1313 were followed up at age 18 years. Height was measured, and age of pubertal onset was collected at age 18 years. Cluster analysis was performed on the five puberty events in boys and girls and linear regression was applied with the clusters predicting height at age 18 years. Individual linear regression analyses assessed the age of onset of each pubertal event as a potential predictor for height at age 18 years. Of the 1313 children followed up at age 18 years, 653 were males and 660 were females. All puberty variables had high internal consistency. In girls, earlier age of menarche, breast development, and growth spurt were related to shorter height. In boys, earlier age of growth spurt and slower progression through puberty were related to taller height at age 18 years. Given that boys and girls may have opposing associations between pubertal timing and adult height and that height is an important predictor of lung function, the effect of pubertal timing on respiratory health should be explored.

Effect of atomoxetine on Tanner stage sexual development in children and adolescents with attention deficit/hyperactivity disorder: 18-month results from a double-blind, placebo-controlled trial

Objective:To determine the effects of long-term atomoxetine treatment on sexual development in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) as compared with placebo and with a national US survey in non-Hispanic white children and adolescents.Methods:This double-blind, placebo-controlled, relapse prevention, multicenter trial was conducted in pediatric patients (6–15 years) with DSM-IV diagnosed ADHD and lasting for ∼18 months. All patients received 10 weeks of open-label atomoxetine treatment (0.5–1.8 mg/kg/day). Patients responding in the last 2 weeks of treatment were randomized to double-blind treatment with either placebo or atomoxetine for up to 9 months, after which atomoxetine patients were re-randomized to either continued atomoxetine treatment or to placebo for up to another 6 months. Patients randomized to placebo at first randomization remained on placebo. The Tanner stage was assessed by the investigator at baseline and at approximately 6, 12, and 18 months, and the rate of sexual development (change in the Tanner stage) was compared between treatment groups.Results:No statistically significant differences were observed between treatment groups either in sexual development (mean time, in days, to the first Tanner stage change: atomoxetine, 464.3 ± 23.0; placebo, 433.1 ± 14.4; p = 0.33) or in the duration of treatment exposure (atomoxetine, 315.3 days; placebo, 315.1 days; p = 0.90). Similar proportions of patients had at least one Tanner stage increase (atomoxetine: 27.1%; placebo: 31.9%; p = 0.39). Proportions of patients in each baseline Tanner stage group moving to higher stages were not statistically significantly different (p = 0.88, p = 0.18, p > 0.99, p = 0.68 for baseline Tanner stages 1–4, respectively). The puberty onset age was similar across treatment groups and consistent with US normative data.Conclusions:Long-term atomoxetine treatment was not associated with any appreciable impact on or delay in sexual maturation in children with ADHD compared with US normative data.Limitations:Study limitations include the relatively short duration of exposure to atomoxetine treatment, and the fact that half of the patients had been previously treated with stimulants. In addition, the Tanner stage data were collected as a secondary measure.Clinical trial registration:Trial was completed prior to the requirement to post trials at initiation and therefore does not have a registration number.

Onset of Puberty: Younger Still

Investigators examined age of puberty onset in a U.S. longitudinal study of 1239 racially and ethnically diverse girls aged 6 to 8 years at enrollment

The survey of puberty timing in healthy boys in Daqing city in northern China

To investigate the puberty timing in healthy adolescent boys in Daqing city in northern China. A cross-sectional and longitudinal combined survey was performed. On 150 male students aged 6-15. Follow up was conducted for 4 years. The serum levels of luteinizing hormone (LH), Follicular Stimulating Hormone (FSH) and total testosterone (TT) were measured. The puberty timing and anthropometry including the body height, weight, and genital development according to Tanner's stages were all recorded. The mean age of puberty onset in healthy adolescent boys is (12.0+/-1.6) years. The growth velocity in the first year after puberty onset is (6.9+/-0.4) cm/year. The level of plasma TT at the time of puberty onset is (1.0+/-0.3) nmol/L. The puberty timing of boys in the Daqing city, northern China is in the range from 8 to 14 years.

Puberty onset in Northern Italy: A random sample of 3597 Italian children

Entering puberty is one of the most important milestones in life. Studies from around the world have shown that age of pubertal changes onset can vary with race and ethnicity, environmental conditions, geographical location and nutrition. In the last century, the onset of puberty progressively shifted back towards younger ages in several European countries, with a levelling off in the last decades. The aim of our study was to describe the prevalence of secondary sexual characteristics in a group of children living in Northern Italy comparing them with the percentile values published by Tanner in 1976. We enrolled 3496 children drawn from public schools and evaluated height, weight and pubertal stages. The analysis of our data evidenced that the 50th percentile age of puberty onset in both sexes decreased by about 1 yr compared to data published by Tanner. Mean body mass index (BMI) z-score was significantly higher (p = 0.01) in pubertal than in pre-pubertal girls, on the contrary it was higher (p = 0.005) in pre-pubertal than in pubertal boys. In conclusion, our study found that girls and boys of our region are beginning pubertal development about 1 yr earlier than Tanner's British population. Taking into consideration the 3rd percentile age for Tanner's breast stage 2 in girls and testicular volume (TV) of 4 ml in boys, the current internationally used cut-off age for precocious puberty, i.e. 8 yr for girls and 9 yr for boys, can be maintained in our population.

Feeding melengesterol acetate (MGA) in advance of estrus synchronization of virgin beef heifers

The objective of this experiment was to determine if a 7-day feeding of melengesterol acetate (MGA) about 2 months before the breeding season would have an effect on puberty onset, response to estrous synchronization, and fertility. "Progesterone priming" with MGA increased the number of heifers that began cycling before estrous synchronization. This did not increase the percentage of heifers that were observed in standing heat after estrous synchronization, however, regardless of whether standard MGA/PGF or Select Synch protocol was used. The conception rates and overall pregnancy rates were similar between treatments. Many factors affect the reproductive performance of replacement heifers; slight decreases in the age of puberty onset seem to have little effect.

Chronic Activation of Dopamine Receptors in the Female Infantile Rat: Effect on Hypophyseal Hormones and on the Onset of Puberty*

In the female rat the period from days 7-20 of age is special with regard to regulation of hypophyseal hormone secretion. This period is characterized by high FSH levels and the occurrence of sporadic LH peaks. As it has been reported that haloperidol could enhance both gonadotropins at 12 days of age and not at later ages, it was of interest to treat rats during the infantile period with pergolide, a dopaminergic agent of long action, and evaluate its effect on hormone levels and puberty onset. Three different schedules of drug injections were applied: 1) daily injections (0.05 mg/kg.day) on days 1-10, 2) daily injections on days 5-14, and 3) daily injections on days 11-20. It was found that only animals treated with daily injections of pergolide on days 11-20 showed an advance in the age of vaginal opening and first estrus compared to distilled water-injected controls. Thus, the rest of the experiments were performed using injection schedule 3. In this group of animals serum LH and FSH levels were decreased 3 and 6 days after the beginning of pergolide treatment (13 and 16 days of age); at 19 days of age pergolide did not modify gonadotropin levels. One day after the end of pergolide treatment (day 21 of age), there was a rebound in LH levels in drug-injected rats, and a nonsignificant increment in FSH levels was observed. There were no differences in serum gonadotropin levels on days 22, 23, and 25 or peripubertally (29, 33, or 36 days of age). On the other hand, pergolide did not significantly modify PRL levels during the treatment, probably due to the already low values of PRL at these ages. Furthermore, PRL levels were not different between control and pergolide-injected rats at all other ages studied. After puberty onset, animals were observed for eight consecutive cycles, and both groups cycled regularly. Furthermore, PRL and gonadotropins levels were similar at diestrus and proestrus. To evaluate if pergolide treatment during the infantile period had caused permanent alteration in dopamine receptor sensitivity, animals were injected with haloperidol (0.1 or 0.25 mg/kg), and PRL release was evaluated. There were no differences in the hyperprolactinemic effect of the drug between groups. Finally, gonadotropin sensitivity to LHRH was similar in adult female rats in proestrus of both groups. The present results suggest that chronic activation of dopamine receptors during the infantile period evokes specific responses on gonadotropin secretion and advances the age of puberty onset.(ABSTRACT TRUNCATED AT 400 WORDS)

Male siblings inhibit reproductive activity in female pine voles, Microtus pinetorum.

Pine vole females paired in breeding cages with male siblings remain unreproductive beyond the age of puberty onset. In this study only 10% of females caged with their brothers reproduced, whereas 85% of females placed with strange males had litters. Mating between a female and a strange male was also suppressed by the presence of a male sibling sequestered behind a wire mesh barrier in the breeding cage. When the sibling male was removed from the cage after 1 day, 78% of the females produced litters. When the sibling remained behind the barrier in the breeding cage, only 42% gave birth to young conceived in his presence. Conception of second litters during the postpartum estrus occurred in over 80% of females caged with strange males alone and only 10% of females caged with sibling males. Female pine voles are induced to become reproductively active by strange males but this activity is depressed by the presence of a brother, and once initiated it does not continue if the female is caged with her brother.