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2.
Horm Res ; 56(1-2): 45-50, 2001.
Article in English | MEDLINE | ID: mdl-11815727

ABSTRACT

OBJECTIVE: This study aimed at the evaluation of the subjective experience and long-term behavioral and psychological effects of precocious puberty (PP). METHODS: 19 female patients who had been treated with GnRH agonists participated in a semistructured interview and completed two standardized checklists. Their parents completed the Child Behavior Checklist (CBCL). RESULTS: The CBCL yielded significantly elevated Internalizing and Total Behavior Problem scores. An elevated risk was found for patients with short adult stature and a relatively late onset of PP. The latter tended to neuroticism, to accentuation of their physical appearance, and felt significantly more insecure than age-related non-PP girls. CONCLUSION: Our findings suggest that PP can lead to specific behavioral problems, and that patients with a risk factor may need psychosocial support.


Subject(s)
Adaptation, Psychological , Gonadotropin-Releasing Hormone/agonists , Puberty, Precocious/drug therapy , Puberty, Precocious/psychology , Adolescent , Adult , Body Height , Female , Forecasting , Humans , Mental Disorders/etiology , Neurotic Disorders/etiology , Puberty, Precocious/pathology
4.
Gynecol Endocrinol ; 14(2): 105-10, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10836197

ABSTRACT

A well-documented case of non-mosaic Turner syndrome, with spontaneous pubertal development and ovulatory cycles is reported. Mosaicism could be excluded both by karyotyping of 172 metaphases of blood lymphocytes and fibroblasts, and by fluorescence in situ hybridization, using an X-centromeric probe, in 200 blood lymphocyte nuclei. This Turner syndrome patient underwent normal pubertal development, with spontaneous menarche at 14 years, followed by regular monthly periods. Hormonal measurements performed during puberty were consistent with the patient's pubertal development. At the age of 26 years the patient was referred for complete fertility evaluation. Detailed hormonal analyses were performed in a given cycle. They showed midluteal phase estradiol and progesterone values within the range corresponding to normal ovulation and corpus luteum function. In the same cycle, pelvic ultrasonography was also performed at days 13, 15 and 18. It demonstrated a spontaneous ovulation, with follicular rupture that occurred between days 15 and 18. This is the first report of a spontaneous ovulation in Turner syndrome evidenced, not only by hormonal analysis, but also by ultrasonographic demonstration of follicular rupture.


Subject(s)
Ovary/diagnostic imaging , Ovulation , Turner Syndrome/physiopathology , Adult , Estradiol/blood , Female , Follicle Stimulating Hormone/blood , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Luteinizing Hormone/blood , Mosaicism , Progesterone/blood , Puberty , Turner Syndrome/diagnostic imaging , Turner Syndrome/genetics , Ultrasonography
5.
J Pediatr Endocrinol Metab ; 12(1): 39-46, 1999.
Article in English | MEDLINE | ID: mdl-10392347

ABSTRACT

After transfer of diabetic patients from porcine to human insulin, many reports emerged supporting an increased hypoglycemia unawareness. Several studies were then undertaken in both diabetic and healthy adults to investigate counterregulatory hormone responses to both porcine and human insulin-induced hypoglycemia as a possible underlying cause for this different hypoglycemia awareness. Most studies demonstrated similar neuroendocrine responses to both insulin species in adults. However, no such studies have ever been performed in healthy children. We undertook a double-blinded study of counterregulatory hormone responses to both porcine and human insulin-induced hypoglycemia in 17 short normal children randomly assigned to two groups, one receiving human and the other porcine insulin. We found similar responses of growth hormone, cortisol, epinephrine, norepinephrine and dopamine to both porcine insulin- and human insulin- induced hypoglycemia. Interestingly, we observed a significantly higher glucagon secretion when hypoglycemia was induced by human insulin. In conclusion, human insulin induces a higher glucagon secretion in healthy children than porcine insulin. Evidently, this observation cannot be extrapolated to diabetic patients. This study, however, further underlines the importance of performing investigations in children, since results found in adults differ from those observed in children.


Subject(s)
Glucagon/metabolism , Growth Disorders/blood , Hypoglycemia/blood , Insulin/pharmacology , Adolescent , Animals , Blood Glucose/metabolism , Catecholamines/blood , Child , Double-Blind Method , Female , Glucagon/blood , Growth Hormone/blood , Humans , Hydrocortisone/blood , Hypoglycemia/chemically induced , Male , Species Specificity , Swine
6.
J Pediatr Endocrinol Metab ; 11(6): 733-7, 1998.
Article in English | MEDLINE | ID: mdl-9829228

ABSTRACT

In salt-losing congenital adrenal hyperplasia (CAH), continuous therapy with glucocorticoids and 9 alpha-fluorohydrocortisone (9 alpha-F) remains the golden rule. Previous reports showed a growth promoting effect of 9 alpha-F therapy. In addition, 9 alpha-F seemed to have a negligible glucocorticoid action. To confirm these facts, we analyzed the clinical data and the biological markers of control of therapy in two groups of patients with salt-losing CAH aged from 2 to 12 years: group I: before (time 0) and 6 months after the increase in 9 alpha-F dosage (time +6); group II: at time 0 and time +6 but without change in 9 alpha-F dosage. Groups were similar in terms of mean age, bone age and hydrocortisone dose. The mean dose of 9 alpha-F was 68.2 +/- 5.0 micrograms/m2/d at time 0 and was increased to 98.6 +/- 7.7 micrograms/m2/d at time +6 in group I; it remained similar in group II. In group I, height velocity decreased significantly from 8.1 +/- 0.6 at time 0 to 6.3 +/- 0.3 cm/yr at time +6 (p < 0.01) while in group II there was no significant change. In group I, plasma renin activity decreased from 10.4 +/- 1.6 at time 0 to 3.9 +/- 1.1 ng/ml/h at time +6 (p < 0.005) and showed no change in group II. These preliminary results suggest that careful monitoring of 9 alpha-F is essential to control a proper growth rate.


Subject(s)
Adrenal Hyperplasia, Congenital/drug therapy , Adrenal Hyperplasia, Congenital/metabolism , Drug Monitoring , Fludrocortisone/administration & dosage , Mineralocorticoids/administration & dosage , Sodium Chloride/metabolism , Adrenal Hyperplasia, Congenital/pathology , Body Height/drug effects , Child , Child, Preschool , Dose-Response Relationship, Drug , Female , Fludrocortisone/therapeutic use , Hormones/blood , Humans , Male , Mineralocorticoids/therapeutic use , Treatment Outcome
7.
J Neuroendocrinol ; 10(8): 627-33, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9725715

ABSTRACT

In many species, delayed sexual maturation occurs when metabolic conditions are not satisfactory. Recently, leptin was shown to be involved in the regulation of food intake and body mass. Furthermore, leptin administration was shown to advance sexual maturation in mice and to rescue sexual function in adverse metabolic conditions. We examined plasma leptin levels in female rats during development and evaluated the role of leptin on sexual maturation in rats subjected to food restriction. In normal rats, plasma leptin levels were low at day 24 of life, then steadily increased during the juvenile period, reaching 740+/-56 pg/ml at 40 days at time of vaginal opening (VO) and further increasing by day 60 (957+/-73 pg/ml). Food restriction initiated at day 25 strongly impaired this increase, in proportion to the severity of the restriction. With a daily food intake reduced to 7-8 g/day, that permanently prevented VO, plasma leptin levels were very low at day 53 (169+/-67 pg/ml). Following switch to ad libitum feeding, plasma leptin reached high levels within 2 days (1577+/-123 pg/ml), and VO occurred 4 days later. If the severe food restriction was maintained and a central infusion of leptin (10 microg/day) was initiated, a significant decrease in body weight compared with vehicle-infused controls was observed. In these conditions, VO occurred in eight out of the nine leptin-treated rats, representing induction of the process of sexual maturation confirmed by increases in ovarian and uterine weights. This induction of sexual maturation exclusively results from a central effect of leptin because no leak of the i.c.v. administered leptin to the general circulation was observed. These data suggest that the rising plasma levels of leptin in the prepubertal period represent a signal to the brain indicating that the young animal is metabolically ready to go through the process of sexual maturation.


Subject(s)
Brain/drug effects , Food Deprivation , Proteins/administration & dosage , Sexual Maturation/drug effects , Animals , Female , Infusion Pumps, Implantable , Leptin , Mice , Proteins/metabolism , Proteins/pharmacology , Rats , Rats, Sprague-Dawley
8.
Mol Cell Endocrinol ; 140(1-2): 107-13, 1998 May 25.
Article in English | MEDLINE | ID: mdl-9722177

ABSTRACT

The discovery of leptin has generated an extraordinary interest in the field of obesity but also in the understanding of the relationship between metabolic status and the neuroendocrine system. Following the initial demonstration that leptin administration to fasting mice can 'protect' neuroendocrine secretions and prevent the changes that are associated with fasting, the concept has emerged that a normal leptin secretion is a prerequisite for normal neuroendocrine secretions. Several unfavorable metabolic situations are associated with low plasma leptin, increased secretion of hypothalmic neuropeptide Y (NPY), and hypogonadism, and a causal relationship has been evoked. Severe dietary restriction in juvenile female rats is associated with low plasma leptin and sexual immaturity. Cessation of food restriction leads to immediate increase in plasma leptin followed 4 days later by vaginal opening. If food restriction is maintained, central leptin infusion can induce sexual maturation, thus demonstrating that leptin can act as a signal for the onset of puberty. In untreated type-I diabetic rats, hypogonadism is associated with very low plasma leptin and increased hypothalmic NYP synthesis and oestrous cyclicity. Fasting rapidly inhibits growth hormone (GH) secretion in association with low plasma leptin and elevated hypothalmic NPY. Central infusion of leptin to fasting rats was able to completely prevent the collapse of GH secretion and to maintain a normal low NPY synthesis. In summary, normally elevated plasma levels appear to be a prerequisite for normal GH and gonadotropin secretion in the rat. Degradation of metabolic conditions results in a rapid reduction of circulating leptin that could represent the signal for several alterations of neuroendocrine secretions. At the level of the hypothalamus, leptin could act on NPY neurons to transduce part or all of this 'metabolic' message. The possibility that changing plasma levels for leptin also affect peripheral endocrine targets, such as pituitary, ovary, adrenal or pancreas, is likely since these endocrine organs express functional long-term leptin receptors.


Subject(s)
Neuropeptide Y/physiology , Proteins/physiology , Sexual Maturation/physiology , Animals , Diabetes Mellitus, Type 1/physiopathology , Female , Food Deprivation , Growth Hormone/metabolism , Leptin , Proteins/metabolism , Rats
10.
Am J Med Genet ; 70(3): 222-8, 1997 Jun 13.
Article in English | MEDLINE | ID: mdl-9188657

ABSTRACT

We describe a 17-year-old girl with mild Prader-Willi syndrome (PWS) due to 15q11-q13 deletion. The deletion occurred on a paternal chromosome 15 already involved in a translocation, t(Y;15)(q12;p11), the latter being present in five other, phenotypically normal individuals in three generations. This appears to be the first case of PWS in which the causative 15q11-q13 deletion occurred on a chromosome involved in a familial translocation, but with breakpoints considerably distal to those of the familial rearrangement. The translocation could predispose to additional rearrangements occurring during meiosis and/or mitosis or, alternatively, the association of two cytogenetic anomalies on the same chromosome could be fortuitous.


Subject(s)
Chromosome Deletion , Chromosomes, Human, Pair 15 , Prader-Willi Syndrome/genetics , Translocation, Genetic , Y Chromosome , Adolescent , Blotting, Southern , DNA, Satellite , Female , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Pedigree
11.
Horm Res ; 48(1): 35-40, 1997.
Article in English | MEDLINE | ID: mdl-9195208

ABSTRACT

Monitoring therapy for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase is difficult, although plasma determinations of 17 alpha-hydroxyprogesterone (17OHP), delta 4-androstenedione (delta 4A) and testosterone are helpful. We have studied the usefulness of monitoring plasma 3 alpha-androstanediol glucuronide (3 alpha-AG) in group of 24 CAH patients aged from birth to 18 years. For comparison, normal values for age and pubertal stage were determined in a control group of 115 girls and 118 boys. Mean plasma levels were higher during the first year of life, decreased to a nadir between 1 and 4 years, and increased steadily thereafter, there was also a significant increase with pubertal stage. In 24 pairs of blood samples obtained at the time of venopuncture and 2 h after, 3 alpha-AG levels did not change (p > 0.05) demonstrating that 3 alpha-AG levels were not affected by stress. In the patients with CAH, positive correlations between plasma 3 alpha-AG and delta 4A (females, r = 0.73; males, r = 0.98), 17OHP (females, r = 0.58; males, r = 0.84) and testosterone (females, r = 0.83; males, r = 0.97) were observed. Concordance between 3 alpha-AG and delta 4A was observed in 90% of all samples, and in 91% between 3 alpha-AG and testosterone. Our study demonstrates that 3 alpha-AG is a valid marker of control and its determination appears to be a reliable tool to monitor CAH.


Subject(s)
Adrenal Hyperplasia, Congenital , Adrenal Hyperplasia, Congenital/blood , Androstane-3,17-diol/analogs & derivatives , 17-alpha-Hydroxyprogesterone/blood , Adolescent , Adrenal Hyperplasia, Congenital/enzymology , Aging/blood , Androstane-3,17-diol/blood , Androstenedione/blood , Child , Child, Preschool , Female , Humans , Infant , Male , Reference Values , Testosterone/blood
13.
J Pediatr Endocrinol Metab ; 8(1): 73-7, 1995.
Article in English | MEDLINE | ID: mdl-7584702

ABSTRACT

We report here the first case of an association between thalassemia major, hemochromatosis, hypogonadotrophic hypogonadism and Turner's syndrome. The patient is an Albanese girl born in 1980; thalassemia major was diagnosed at 1 year and she was started on a transfusion program; in 1987 iron chelation therapy was started. Six years ago, at 7 years of age, her short stature was observed and she was referred to the endocrinology clinic for evaluation; the basal and stimulation tests done at that time failed to reveal growth hormone deficiency, hypothyroidism or any other disease. Nevertheless, at 12 years old, she was still prepubertal and there was a bone age delay of 1.5 years; a gonadotropin-releasing hormone (GnRH) stimulation test showed no response of either FSH (basal: 0.2 mU/ml; peak: 0.8 mU/ml) or LH (basal: < 0.1 mU/ml; peak: 0.6 mU/ml), suggesting hypogonadotrophic hypogonadism. Small dysmorphies called our attention to the possibility of Turner's syndrome which was confirmed by the karyotype (45 XO/46 XX). In this patient, thalassemia major and its lifelong consequences, namely the hemochromatosis-related hypogonadotrophic hypogonadism, masked the usual hormonal findings of Turner's syndrome.


Subject(s)
Hemochromatosis/etiology , Hypogonadism/etiology , Turner Syndrome/complications , beta-Thalassemia/complications , Adolescent , Female , Follicle Stimulating Hormone/blood , Gonadotropin-Releasing Hormone/pharmacology , Hemochromatosis/blood , Humans , Hypogonadism/blood , Karyotyping , Luteinizing Hormone/blood , Thyrotropin/blood , Turner Syndrome/blood , Turner Syndrome/genetics , beta-Thalassemia/blood
14.
Endocrinology ; 135(2): 509-19, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7518382

ABSTRACT

The importance of normal GH secretion for the onset of sexual maturation is a subject of controversy. Also, the need to achieve a minimal body size or body fat content has been postulated to be of importance for determining the timing of the onset of puberty. To evaluate the importance of GH secretion on the onset of sexual maturation in the female rat, GH deprivation has been induced by treating prepubertal rats with antirat GRF serum to passively immunize these animals against GRF. Chronic administration of anti-GRF serum produced in all series an impressive reduction in growth rate (from 5 to 2 g/day), resulting in a body weight averaging 50-60% the normal value at 50 days of life. Despite this deficit in growth, sexual maturation, as established by vaginal opening and first estrous cycles, occurred at the normal age in three of four series of rats; in one series, however, sexual maturation was delayed by 4 days, but thereafter, all parameters indicated that the gonadotropic axis was normally activated. In one series, fertility was tested at 59 days of age in females with a body weight corresponding to 51% of the control weight; these females conceived and delivered a reduced number of pups (9.4 +/- 0.7 instead of 14.2 +/- 0.8 in control dams), but the pups were of normal size. In a second experimental approach, the effect of GH deprivation was evaluated in a model of late sexual maturation obtained by severe food restriction followed by a switch to ad libitum feeding. Severe food restriction initiated at approximately 28 days, when the body weight was 75 g, drastically reduced the growth rate and completely prevented sexual maturation. A switch to ad libitum feeding at 50 days provoked an important compensatory growth and the occurrence of sexual maturation 4 days later. Passive immunization against GRF during this recovery phase did reduce the growth rate, but did not delay sexual maturation. Plasma insulin-like growth factor-I (IGF-I) secretion was very low in food-restricted rats and in each situation with induced GH deprivation. During food restriction, plasma IGF-binding protein-3 (IGFBP-3) and to a lesser extent IGFBP-1 were decreased, and IGFBP-2 was increased; after switching to ad libitum feeding, plasma levels of IGFBP-2 normalized, but levels of IGFBP-1 and IGFBP-3 remained low in the face of normalized plasma IGF-I levels.(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Fertility/physiology , Growth Hormone-Releasing Hormone/immunology , Growth Hormone/physiology , Immunization, Passive , Sexual Maturation/physiology , Animals , Carrier Proteins/blood , Female , Food Deprivation , Growth Hormone/metabolism , Growth Hormone-Releasing Hormone/physiology , Insulin-Like Growth Factor Binding Proteins , Insulin-Like Growth Factor I/metabolism , Male , Organ Size , Rats , Rats, Sprague-Dawley , Uterus/growth & development , Vagina/growth & development
16.
Endocrinology ; 135(1): 45-52, 1994 Jul.
Article in English | MEDLINE | ID: mdl-8013383

ABSTRACT

The GnRH antagonist Antide has been shown to produce prolonged inhibition of gonadotropin secretion in ovariectomized monkeys and other animal models. The reasons for such a long duration of action have not yet been clarified. To understand the mode of action of this new antagonist, we have performed association and dissociation binding kinetics using either crude rat pituitary homogenates as source of GnRH receptors or dispersed pituitary cells in culture. The binding characteristics of the radioiodinated Antide analog 125I-labeled[D-Tyr0] Antide to GnRH receptors in rat pituitary homogenates were comparable to those of the first generation GnRH antagonist 125I-labeled [Ac(3)Pro1,pFD-Phe2,D-Trp3,6]GnRH or the GnRH agonist 125I-labeled [D-Trp6,(N-Et)Pro9,Des,Gly10]GnRH, with an affinity constant (Ka) in the 10(10) M-1 range. The maximum binding capacity was consistently higher with the antagonist tracers than with the [125I]GnRH agonist. Both antagonists dissociated at a slower rate at 4 C (approximately 4 times) than the [125I]GnRH agonist. Incubation at 23 C of 125I-labeled [D-Tyr0] Antide previously bound at 4 C resulted in complete dissociation within 8 h after the addition of an excess amount of any of the GnRH analogs; in addition, simple dilution of the incubation medium produced spontaneous dissociation at this temperature. Using rat pituitary cells, Antide was found to inhibit the LH response to native GnRH (10(-8) M) in a dose-related manner. To test whether the binding of Antide is normally reversible at 37 C, Antide (10(-7) M) was added to the culture medium 3 days after cell plating, and the initial preincubation was resumed for 24 h. Cells were then washed twice, and dissociation was allowed to take place. Bound Antide was shown to dissociate rapidly at 37 C, as cells previously treated with Antide produced a full LH response within 24 h if challenged with native GnRH. In conclusion, the binding kinetics of 125I-labeled [D-Tyr0]Antide to GnRH receptors, which should reflect those of Antide, did not present abnormal features. Although this antagonist, similar to other GnRH antagonists, dissociated from pituitary receptors at a slower rate than GnRH analogs, rapid and spontaneous dissociation was achieved at 23 C with simple dilution, and dissociation of unmodified Antide occurred at 37 C. Taken together, our results support the concept that the long duration of action of Antide is not due to any toxic effect of Antide at the receptor site and could derive only marginally from the slow dissociation rate of this antagonist.


Subject(s)
Gonadotropin-Releasing Hormone/antagonists & inhibitors , Oligopeptides/metabolism , Pituitary Gland/metabolism , Receptors, LHRH/metabolism , Animals , Kinetics , Male , Pituitary Gland/cytology , Rats , Rats, Sprague-Dawley , Temperature , Time Factors
17.
J Adolesc Health ; 15(3): 258-62, 1994 May.
Article in English | MEDLINE | ID: mdl-8075098

ABSTRACT

PURPOSE: This study aimed at assessing the impact of physical training on psychological functioning at the onset of a prospective study of psychological and somatic maturation of adolescent female athletes. METHODS: Twenty-seven highly trained gymnasts aged 12.7 +/- 1.1 year (mean +/- SD, training load = 18-26 hr/week) and 16 age-matched but moderately trained swimmers (13.0 +/- 0.9 yr, training load 4-15 hr/wk) were submitted to standardized somatic and psychiatric examinations during training camps. RESULTS: Gymnasts were significantly shorter, lighter and thinner (p < 0.001) than swimmers. Their bone age was moderately but significantly retarded (-1.42 +/- 0.99 yr, p < 0.001) in contrast with swimmers in whom it was adequate for chronological age (+0.28 +/- 0.94 year, ns). Only 7.4% of gymnasts had already had menarche in contrast with 50% of age-matched swimmers (p = 0.003). Psychological functioning was considered as normal in all subjects. However, seven athletes including 3/27 gymnasts and 4/16 swimmers (p = 0.394) were considered as subjects "at risk" to develop a manifest mental disorder over time. Ten gymnasts (41.7%) presented with a global delay in psychological maturation, whereas no such case was observed among swimmers (p = 0.015). No correlation could be established between psychological delay and pubertal retardation (p = 0.210). CONCLUSION: Strenuous training in gymnastics for more than 1 yr has so far no detectable interference with the normal maturational events of adolescence. The outcome of athletes at risk to develop psychopathology as well as those with a global delay in psychological maturation who presented as if they were still in the latency period, remains uncertain.


Subject(s)
Growth , Gymnastics/physiology , Gymnastics/psychology , Human Development , Psychology, Adolescent , Swimming/physiology , Swimming/psychology , Adolescent , Age Determination by Skeleton , Child , Female , Growth Disorders/diagnosis , Growth Disorders/epidemiology , Humans , Matched-Pair Analysis , Menarche , Mental Disorders/diagnosis , Mental Disorders/epidemiology , Prospective Studies , Risk Factors
18.
Schweiz Z Med Traumatol ; (3): 7-15, 1994.
Article in French | MEDLINE | ID: mdl-7921796

ABSTRACT

The hormonal response to a short but intense session of physical exercise should be distinguished from the endocrine adaptation to systematic physical conditioning. The normal child is perfectly equipped to handle stress situations such as those generated by leisure sport: the transient increase in stress hormones has no deleterious effect on growth and puberty. For highly trained children and adolescents, standardized dynamic testing will provide little information on the state of their endocrine system. In addition, the effects of training should be differentiated from those of various bias of selection. In young elite athletes, as for adult athletes, the alterations of the endocrine system result from an inappropriate physical conditioning programme for the individual level of tolerance. Whereas it has been shown that the gonadal function is predominantly affected (pubertal delay, menstrual dysfunction), alterations of growth hormone and cortisol productions have also been reported. Anomalies of pubertal growth should be searched for among elite adolescent athletes: there are data suggesting that their growth potential should probably not be affected below 15 weekly hours of training. However, children do not respond to stress in a uniform manner and one should be prepared to detect the occasional athlete with inadequate growth at lower training intensities. This seems to be the case when training starts before puberty as well as in physical activities associated with a strict weight control. When growth and/or puberal progression become inappropriate, the only logical therapy consists in reducing markedly or stopping training temporarily: in this situation, there is no medical justification whatsoever to initiate a substitutive therapy.


Subject(s)
Growth , Hormones/physiology , Sports/physiology , Adolescent , Child , Female , Gonadal Steroid Hormones/metabolism , Growth Hormone/metabolism , Hormones/metabolism , Humans , Male , Pituitary-Adrenal System/metabolism , Puberty/physiology , Thyroid Hormones/metabolism
19.
Pediatr Res ; 34(6): 829-33, 1993 Dec.
Article in English | MEDLINE | ID: mdl-8108202

ABSTRACT

FSH plays an essential role in folliculogenesis and ovarian growth. However, cross-sectional studies have not shown an increase in bioactive FSH (B-FSH) during puberty. To eliminate intersubject variability, we used a longitudinal design and tested the hypothesis that B-FSH increases during puberty. Thirty normal, healthy girls were enrolled in a longitudinal study from pubertal stages I to IV. The subjects were evaluated at 6-mo intervals; each visit consisted of pubertal staging, bone age determination by x-ray, measurements of serum immunoreactive FSH (I-FSH) and B-FSH (n = 14) or immunoreactive LH (I-LH) and bioactive LH (B-LH) (n = 18), and adrenal and ovarian steroids. All girls had clinical and hormonal characteristics of puberty. Both I-FSH and B-FSH levels were relatively elevated before puberty, whereas serum I-LH and B-LH were low. From pubertal stages I to III, there was a modest yet significant rise in serum I-FSH (p < 0.001) and serum B-FSH (p < 0.01). Serum I-LH and B-LH concentrations showed the expected increases with puberty (p < 0.001), with serum B-LH concentrations exhibiting a greater rise than I-LH (p < 0.001). Our results demonstrate that serum B-FSH and I-FSH increase during puberty. Relatively elevated B-FSH concentrations from early to midpuberty may be an important factor for ovarian growth while circulating LH and estrogen are still low. As puberty progresses, the continued and selective increase in LH induces a rise in estradiol and ultimately leads to ovulation.


Subject(s)
Follicle Stimulating Hormone/blood , Luteinizing Hormone/blood , Puberty/blood , Adolescent , Biological Assay/methods , Child , Estradiol/blood , Female , Humans , Insulin-Like Growth Factor I/metabolism , Radioimmunoassay , Time Factors
20.
Endocrinology ; 133(4): 1891-4, 1993 Oct.
Article in English | MEDLINE | ID: mdl-8404631

ABSTRACT

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.


Subject(s)
Food Deprivation/physiology , Neuropeptide Y/physiology , Neurosecretory Systems/metabolism , Sexual Maturation/physiology , Animals , Eating/physiology , Female , Insulin-Like Growth Factor I/metabolism , Neuropeptide Y/pharmacology , Rats , Rats, Sprague-Dawley , Sexual Maturation/drug effects
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