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PubMed2000

Effects of delaying puberty on bone mineralization in female rats.

The effect of delaying puberty on bone mineralization was studied using female rats as a model. Repeated injections of gonadotrophin-releasing hormone antagonist (GnRHa) were used to suppress the onset of puberty from the age of 6-10 weeks. A group of control female rats was given aqueous solution injections at the same age and for the same duration. The effect of delaying puberty on bone mineralization was examined using dual energy X-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (QCT), both methods being adapted for small animals. Bone mineral parameters were measured at baseline and at the ages of 10, 17 and 24 weeks in total body, femur and spine. Compared to controls, bone mineral content (BMC) and bone mineral density (BMD), as measured by DXA, were significantly decreased in GnRHa-treated rats in total body and femur at 10 and 24 weeks of age (P < 0.05). The results were even more significant after adjusting for weight. After this adjustment, spine BMC and BMD at 10, 17 and 24 weeks were significantly lower in the treatment group (P < 0.05). Trabecular BMD at the distal femur in the GnRHa treated group as measured by peripheral QCT was significantly lower (P < 0.05). However, cortical bone in the mid-femur had higher BMD, concurrent with lower cortical thickness in the treatment group. In conclusion, a delay in the onset of sexual maturation may cause prolonged, possibly irreversible defect in bone mineralization.

Absorptiometry, Photon↗
PubMed2006

Follow-up study of two sisters with type A syndrome of severe insulin resistance gives a new insight into PCOS pathogenesis in relation to puberty and pregnancy outcome: a case report.

We report two sisters with profound insulin resistance associated with a novel heterozygous missense mutation in exon 19 (His1130Arg) of the insulin receptor gene. The eldest was seen after puberty at age 15 and she presented a severe form of polycystic ovary syndrome (PCOS) with biological hyperandrogenism (HA) mimicking a virilizing tumour. However, she has been able to ovulate under clomiphene citrate (CC) and to achieve two uneventful pregnancies. The patient had no glucose tolerance abnormality during pregnancies. The outcome of pregnancy was good except for a low birthweight. The youngest sister was seen earlier in life (at age 11) before puberty. First, she developed polycystic ovaries (PCO), seen under ultrasound scan, and later also developed full PCOS. This second finding gave us the opportunity to observe that PCO developed before and at the beginning of puberty despite low LH levels. We postulate that the development of PCO was the consequence of an LH-independent intra-ovarian HA likely induced by the severe hyperinsulinism in the context of genetic abnormalities.

Adolescent↗
PubMed1999

Physiological perspectives on leptin as a regulator of reproduction: role in timing puberty.

How nutrition regulates reproductive activity remains a major unsolved question of reproductive biology. Reducing the level of nutrition during adulthood can lead to infertility, primarily through reduction of GnRH secretion. Inquiry about such a mechanism has its roots in the search for cues timing the onset of fertility, because the tempo of sexual maturation is much more closely associated with body growth than with chronological age. Growth depends on the quantity and quality of food intake. When food availability is low, small, short-lived species with high metabolism and reduced growth may not even attain puberty before they die. In longer-lived species, puberty is delayed for months or even years until more food becomes available. To appreciate fully how the pubertal progression is timed will require understanding how peripheral signals relating information about energy metabolism are sensed by the brain and how such information is routed through pathways controlling GnRH secretion. Here, we provide some background and physiologic perspective on the question of whether the fat-derived hormone leptin is the unique peripheral signal, is an important signal, is but one of a constellation of signals, or is not a signal timing puberty.

Aging↗
PubMed2001

Puberty in perinatal HIV-1 infection: a multicentre longitudinal study of 212 children.

OBJECTIVE: To define age at entry into Tanner stages in children with perinatal HIV-1 infection. DESIGN: Multicentre longitudinal study including 212 perinatally HIV-1-infected children (107 girls and 105 boys) followed-up during puberty (from 8 and 9 years onwards in girls and boys, respectively). Healthy children (843 girls and 821 boys) provided reference percentiles. P2 or B2 stages in girls and P2 or G2 stages in boys defined onset of puberty. METHODS: The cumulative probability [95% confidence limit (CI)] of entry into each stage at different ages was estimated by the Kaplan-Meier product-limit method; differences were evaluated by log rank test. Relationships were tested using the Spearman's rank correlation coefficient. RESULTS: Ages of girls [years (95%CI)] at P2 [12.9 (12.6-13.2)], P3 [13.4 (13.0-13.8)], P4 [14.6 (14.0-15.2)], B2 [12.7 (12.2-13.2)], B3 [13.3 (12.8-14.0)] and B4 [14.6 (14.0-15.2)] stages were > 97th percentile (> or = 21 month delay) of controls. Ages of boys [years (95%CI)] at P2 [12.6 (12.1-13.1)], P3 [13.9 (13.4-14.4)], P4 [14.9 (14.2-15.6)], G2 [12.1 (11.5-12.7)], G3 [13.6 (13.1-14.1)] and G4 [14.9 (14.1-15.7)] stages were at the 75-97th percentiles (< or = 15 month delay). Age at onset of puberty was not related to clinical and immunological condition, antiretroviral treatment, weigh for height and age at onset of severe disease or immune suppression. CONCLUSION: Perinatal HIV-1 infection interferes with sexual maturation. The mechanisms by which this occurs should be elucidated and intervention strategies designed. Intervention could save much psychological distress, since associated linear growth failure can exacerbate adolescents' feelings of being different and unwell.

Adolescent↗
PubMed1978

Asymmetric ovarian enlargement in idiopathic precocious puberty.

A patient with precocious puberty is presented in whom the pneumogynogram showed only one enlarged ovary. Because tumor could not be excluded, the patient had exploratory operation six weeks later. Both ovaries and the uterus were enlarged, compatible with the central stimulation seen in idiopathic precocious puberty. Care should be used in interpreting pneumogynograms as evidence of possible ovarian tumor in young girls with precocious puberty who have only modest unilateral ovarian enlargement.

Child↗
PubMed2007

Effects of lifestyle on the onset of puberty as determinant for breast cancer.

Breast cancer is more than ever the leading cause of death in women. In this article, we investigate the influence of lifestyle factors, and in particular nutrition (i.e. soft drinks), on physical development, puberty, breast growth and menarche to understand the potential impact of these environmental and lifestyle factors on the induction of breast cancer susceptibility. A questionnaire was obtained from 1146 girls of 10 schools in Belgian Limburg, attending the second year of secondary school. Their mean age was about 13 years. The analyses of the data were performed with 'survival analysis', in particular with the 'Cox regression' model for menarche. This project was conducted in the school year of 1999-2000. In the univariate and multivariate analysis investigating the most important variables of the period from birth to the age of menarche, there was clear evidence that lifestyle factors, including nutrition, have an effect on breast development and menarche. The following variables were significantly related to breast development and menarche: body mass index, drinking high-carbohydrate drinks, i.e. soft drinks, height of the father and the mother, weight of the mother at the start of pregnancy, history of mononucleosis, origin and education of the parents and physical activity. Lifestyle factors, including nutrition (i.e. soft drinks), affect the age at puberty and menarche. The same factors are known to be related to breast cancer risk. Better control of these variables during puberty might reduce breast cancer risk later in life.

Age Factors↗
PubMed1978

Hypothalamo-pituitary-gonadal function in male central precocious puberty.

Eleven boys aged 1-10 years with central precocious puberty were studied. According to the pubertal development six were classified as P2, one as P3 and four as P5. In all cases plasma testosterone levels were definitely elevated (1.7-5.8 ng/ml) when compared with pre-pubertal controls. Peak values after HCG (3 X 1500 units) in four of the boys were in the high adult range. The binding capacity of serum testosterone oestradiol binding globuline (TeBG) ranged between 0.5 and 7.30 microgram/dl. Basal plasma levels of LH and FSH were respectively 2.06 +/- 0.64 and 1.2 +/- 0.25 miu/ml, and peak levels after LHRH (0.1 mg/m2) 13.9 +/- 3.7 and 2.6 +/- 0.43 miu/ml respectively. The data demonstrated a significant increase of plasma testosterone and post LHRH LH peak levels in boys with central precocious puberty when compared with pre-pubertal controls. The patients at stage P2 exhibited high levels of plasma testosterone contrasting with the degree of pubertal maturation, high values of TeBG and low response to LHRH which were in the pre-pubertal range. These findings suggest that the testicular sensitivity to LH increases early in boys with central precocious puberty, while the testosterone responsiveness, both at peripheral and hypothalamic levels, is delayed.

Child↗
PubMed1980

Twenty-four hour profiles of serum prolactin during male puberty with and without gynaecomastia.

Twenty-four hour profiles of circulating prolactin have been documented in eight boys with simple delayed puberty, eleven with gynaecomastia, three of whom were retested following its spontaneous resolution, and two normal adult men. Mean 24 h prolactin levels in four boys with delayed puberty and ten with gynaecomastia exceeded the mean levels for the two adult men. A sleep-associated rise in prolactin levels occurred at all stages of puberty irrespective of the presence or absence of gynaecomastia, and in some subjects peaks also occurred during the daytime. Boys with gynaecomastia had higher 24 h means levels of prolactin (P less than 0.05), higher daytime levels (P less than 0.05) and higher sleep-associated levels (P less than 0.05) than did control subjects. These were not related to the degree or duration of the gynaecomastia, but 24 h mean levels of prolactin and oestradiol were positively correlated. In one subject who had had transient galactorrhoea, high levels of circulating prolactin, oestrone and oestradiol fell following spontaneous resolution of the gynaecomastia. We believe that oestrogen: androgen imbalance during the daytime is the major cause of pubertal gynaecomastia, with hyperprolacinaemia (which may cause galactorrhoea) sometimes occurring as a response to relative hyperoestrogenaemia.

Adolescent↗
PubMed1980

Decreased LH response to the second of consecutive day luteinizing hormone releasing hormone (LHRH) in fusions among patients with constitutional delay of puberty: a phenomenon of pubertal maturation?

Consecutive day LHRH stimulation by continuous infusion has been used to evaluate pituitary reserve. Different responses on the 2 days were not present among non-pubertal hypopituitary patients, pubertal growth hormone deficient patients or adult males. However, patients with constitutionally delayed puberty demonstrated a greater serum LH response on day 1 than day 2. Urinary LH responses suggest a similar but not statistically significant pattern. This response may be a normal phenomenon of puberty or may represent part of the reason for constitutionally delayed puberty.

Adolescent↗
PubMed1982

Plasma androgenic activity in women with acne vulgaris and in healthy girls before, during and after puberty.

The possible relationship between plasma androgenic activity and acne vulgaris was investigated. Plasma testosterone and sex hormone binding globulin (SHBG) levels were determined in healthy girls during different stages of puberty, in healthy adult women and in women with acne vulgaris. Testosterone increase during puberty, whereas SHBG decreased during the early stages before it increased and stabilized plasma concentrations of testosterone and SHBG. Women with severe acne vulgaris had testosterone levels in the same range but the SHBG levels were significantly lower than those of healthy women and women with mild acne. These results show a high androgenic activity in the intermediate stages of puberty, when acne vulgaris is a common complaint and an increased androgenic activity in adult women with severe acne vulgaris.

Acne Vulgaris↗
PubMed1985

Spontaneous gonadotrophin pulsatility and ovarian morphology in girls with central precocious puberty treated with cyproterone acetate.

We have studied four girls with central precocious puberty treated with cyproterone acetate for a mean of 3.6 years (range 1.5-6.3 years). Pelvic ultrasound assessment demonstrated suppression of the ovarian morphology of central precocious puberty despite the presence of spontaneous pulsatile gonadotrophin secretion at night. We suggest that the previously reported effects on gonadotrophin secretion induced by cyproterone acetate therapy, administered in recommended doses, are minor and that the predominant effect of cyproterone acetate in the treatment of girls with central precocious puberty is direct inhibition of ovarian steroidogenesis.

Child↗
PubMed1988

Prolactin response to metoclopramide does not distinguish patients with hypogonadotrophic hypogonadism from delayed puberty.

The prolactin response to metoclopramide (MCP) was studied in 23 sexually immature males, 14 with isolated hypogonadotrophic hypogonadism (IHH) and nine with constitutional delayed puberty. Six of the 14 IHH patients had not been treated prior to our study, whereas eight had received long term therapy with testosterone or hCG for variable periods ranging from 1 to 20 years. We also measured the prolactin response to chlorpromazine (CPZ) in the untreated IHH men. In these untreated subjects, we observed a greatly diminished prolactin response after CPZ by comparison to that measured following MCP administration (peak 15 ng/ml, areas 86 units vs peak 43 ng/ml, area 416 units, respectively) (P less than 0.01). Furthermore, prolactin levels following MCP were similar in untreated (peak 43 ng/ml, area 416 units) and treated (peak 55 ng/ml, area 545 units, NS) IHH males as well as in boys with constitutional delayed puberty (peak 50 ng/ml, area 532 units, NS). In addition, responses in the three groups of patients were about half (P less than 0.01) those measured in normal men (peak 81 ng/ml, area 845 units). These data indicate that, unlike CPZ, MCP is not useful in distinguishing patients with hypogonadotrophic hypogonadism from boys with constitutional delayed puberty.

Adolescent↗
PubMed1989

Urinary growth hormone during puberty in normal and diabetic children.

The measurement of GH in urine may have many clinical applications, particularly in childhood. We have used a highly sensitive direct immunoradiometric assay to examine urinary GH excretion in children during puberty. Fifty-five healthy schoolchildren collected timed overnight urine samples. A further 36 children (15 normal, six of short stature and 15 diabetic) collected urine samples during a total of 50 overnight plasma GH secretory profiles (15-min sampling). Overnight urinary GH excretion increased during puberty, with a peak at breast stage 2 in girls, and genital stage 4 in boys, before declining at stage 5. There was a positive correlation (r = 0.57, p = 0.003) with height velocity in girls, but not in boys. At each puberty stage except 2, the diabetics excreted more urinary GH than the normal children. There was a highly significant correlation (r = 0.79, p less than 0.001) between mean overnight plasma GH concentrations and urinary GH excretion, suggesting that the latter accurately reflects physiological GH secretion.

Adolescent↗
PubMed1992

Changes in growth hormone concentrations during puberty in adolescents with insulin dependent diabetes.

OBJECTIVE: To document the changes in pulsatile growth hormone secretion in diabetic adolescents during puberty, and to investigate their relationship to both metabolic control and stature. DESIGN: Auxological parameters, overnight growth hormone secretion, fasting IGF-I, hourly glucose and metabolic control were assessed in a group of adolescents with diabetes. PATIENTS: Fifty-two diabetic adolescents (28 males and 24 females) at different pubertal stages and with varying degrees of metabolic control were studied. Ten of those with poor diabetic control were studied on two occasions. MEASUREMENTS: Height and weight measurements, pubertal staging, growth velocity data and bone age estimation were obtained on all the patients. Overnight growth hormone profiles (Pulsar program analysis), glycosylated haemoglobin and fasting IGF-I were performed on all the subjects. Hourly overnight glucose measurements were also obtained on the ten subjects who had two overnight growth hormone studies. RESULTS: For the whole diabetic growth, GH area under curve (AUC) was maximal in late puberty (pubertal stage 4), and was paralleled by maximal GH peak amplitude. No relationship between GH-AUC and metabolic control was demonstrated. No difference in GH parameters was demonstrated between the male and female subgroups. The relationship between growth hormone secretory parameters and stature was not significant. However, GH-AUC was significantly correlated with growth velocity in the males but not the females. CONCLUSIONS: The pattern of GH secretion in adolescents with diabetes parallels that seen in normal adolescents during puberty, with increases in GH concentration associated with increased GH pulse amplitude. The degree of metabolic control had no effect on this pattern and there was no relationship between GH secretory parameters and stature.

Adolescent↗
PubMed1992

Serum levels of growth hormone-binding protein and insulin-like growth factor-I during puberty.

OBJECTIVE: The aim was to investigate the effect of pubertal development on serum levels of growth hormone binding protein (GHBP) and IGF-I, and to study the relationship between GHBP levels and height standard deviation score (SDS), nutritional state and IGF-I levels. DESIGN AND PATIENTS: The investigation was performed on serum samples from 72 healthy adolescents of different pubertal stage. Results were compared to those obtained in 46 prepubertal children. MEASUREMENTS: Serum levels of GHBP were measured by HPLC gel filtration and IGF-I levels were measured by RIA after acid-ethanol extraction. RESULTS: No effect of pubertal stage on serum levels of GHBP was found. A positive relationship was found between serum levels of GHBP and height SDS (r = 0.38; P < 0.005) and weight expressed as percentage of median weight for height age (r = 0.46; P < 0.0005). Serum levels of IGF-I increased during puberty and were not correlated with height SDS or weight for height age. In pubertal subjects, no relationship existed between serum levels of GHBP and IGF-I. In prepubertal subjects, however, a significantly positive relationship between GHBP and IGF-I levels (r = 0.66; P < 0.0005) was found. CONCLUSIONS: Pubertal development does not seem to influence serum levels of GHBP. Height SDS and nutritional state are related to the concentration of GHBP. Before puberty, the level of GHBP is positively related to IGF-I levels; during puberty, however, the increase in serum IGF-I levels is not accompanied by changes in the amount of circulating GHBP.

Adolescent↗
PubMed1993

The effects of oxandrolone on the growth hormone and gonadal axes in boys with constitutional delay of growth and puberty.

OBJECTIVE: We studied the effects of oxandrolone on serum concentrations of LH, FSH, testosterone, GH, SHBG, DHEAS, IGF-I and insulin in boys with constitutional delay of growth and puberty. DESIGN: Ten boys with constitutional delay of growth and puberty, mean age 13.8 years (range 12.4-15.5) were studied. Twenty-four-hour serum concentration profiles of GH, LH and FSH were constructed by drawing blood samples at 20-minute intervals. Three study occasions over a period of 6 months were chosen to assess hormone concentrations before, during and 6 weeks after a 3-month course of oxandrolone (2.5 mg once daily) therapy. RESULTS: Growth velocity increased during oxandrolone treatment and stayed higher after therapy (pre 3.9 +/- 0.5; on 6.3 +/- 0.8; post 6.4 +/- 0.9 cm/year (mean +/- SEM) two way ANOVA, F = 5.3, P = 0.02). Oxandrolone had androgenic effects, suppressing mean serum LH concentrations from 1.7 +/- 0.3 to 1.1 +/- 0.2 U/I and serum testosterone concentrations from 1.9 +/- 0.6 to 0.8 +/- 0.1 nmol/l. SHBG concentrations were also reduced from 130.9 +/- 14.6 to 30.7 +/- 7.3 nmol/l. Serum GH concentration fell slightly from 5.9 +/- 0.6 to 4.8 +/- 0.5 mU/l. After cessation of treatment, there was a significant 'rebound' in mean 24-hour serum LH (2.6 U/l +/- 0.4) and testosterone concentrations (3.2 +/- 0.9 nmol/l) but no change in serum GH concentrations. SHBG values also rose but not to the same extent as those observed before therapy (82.0 +/- 8.4 nmol/l). There were no statistically significant differences in serum concentrations of FSH, DHEAS, IGF-I and insulin over the study period. In a stepwise multiple regression analysis of factors that might influence the growth rate observed, the 24-hour mean serum testosterone concentration and the treatment (on or off) with oxandrolone were the main influences. The relationship was described by the equation Height velocity = 0.69 (24-hour mean serum testosterone concentration)+1.70 (treatment regimen)+3.37 (adjusted R2 = 0.35, F = 8.39, P = 0.001). CONCLUSIONS: Oxandrolone has an androgenic action as shown by changes in serum LH, testosterone and SHBG concentrations and by the lack of effect on FSH. No effect of oxandrolone on the GH axis was documented. We suggest that the growth promoting effects of oxandrolone are related in part to the mild androgenic effects of the steroid and the growth acceleration following oxandrolone withdrawal may reflect increasing total serum testosterone concentrations and decreasing levels of SHBG and progress in puberty.

Adolescent↗
PubMed2005

Final height after treatment of early puberty in short adopted girls with gonadotrophin releasing hormone agonist with or without growth hormone.

OBJECTIVE: To compare final height data after treatment with gonadotrophin releasing hormone agonist (GnRHa) alone or in combination with growth hormone (GH) in short adopted girls with early puberty. DESIGN: A randomized controlled trial. PATIENTS AND METHODS: Twenty-six girls with onset of puberty before 10 years of age were treated for 3 years with either GnRHa alone (group A, n = 12) or with GnRHa and GH (group B, n = 14). Mean age at start of treatment was 9.6 years in both groups, bone age was 10.7 (SD 1.1) years in group A and 11.6 (0.8) years in group B. RESULTS: Initial height prediction with average Bayley & Pinneau tables was 149.8 (5.6) and 146.8 (4.8) cm, respectively. Bone age at discontinuation of treatment was 12.3 (0.9) and 13.0 (0.6) years in group A and B, respectively. Height gain defined as the difference between initial height prediction and attained final height, was significantly different between group A and B (5.2 (3.7) and 8.2 (3.4) cm, P < 0.05) using average tables for height prediction. With accelerated tables for prediction the numbers were -1.0 (3.6) and 3.3 (3.5) cm, respectively. At final height, there was no significant difference in height: group A: 155.0 (5.6) cm and group B: 155.0 (5.5) cm. CONCLUSIONS: After 3 years of GnRHa treatment in adopted girls with early puberty, FH is significantly higher than initial height prediction. The addition of GH resulted in a limited further increase in height gain. In the interpretation of the results methodological issues concerning height prediction have to be taken into account.

Adoption↗
PubMed2005

Kisspeptin and its receptor: new gatekeepers of puberty.

The recent finding that the hormone kisspeptin plays a pivotal role in the onset of puberty is one of the biggest discoveries in human reproductive biology in 30 years. Mutations in the receptor for kisspeptin cause humans and mice to fail to reach puberty and to be sterile. It is the first time since the identification of gonadotrophin-releasing hormone that a single gene is found to have such a dramatic effect on reproduction. This discovery opens new possibilities in the treatment of reproductive disorders such as delayed or advanced puberty, infertility and sex hormone-dependent cancers.

Animals↗