Pulsatile secretion of luteinizing hormone and sleep-related gonadotropin rhythms in girls with premature thelarche

Differential analysis of nutrient intake, insulin resistance and lipid profiles between healthy and premature thelarche Chinese girls

Background

Premature thelarche (PT) is a benevolent ailment affecting young girls. Multiple factors are reported to correlate with this condition, but the mechanisms responsible for the onset of PT have not yet been fully investigated. This study aimed to evaluate the relationship of nutrient intake, insulin resistance and lipid profile with PT.

Methods

Two hundred sixty-three girls with PT, and 222 healthy girls of similar age were enrolled into this study. Their demographics, Tanner stage of breast development, nutrient intake, insulin resistance and lipid profiles were compared.

Results

Daily protein and fat intakes, insulin resistance parameters including serum insulin-like growth factor 1, fasting glucose to insulin ratio, quantitative insulin check index and homeostasis model of assessment of insulin resistance, as well as serum levels of triacylglycerol, total cholesterol and low-density lipoprotein, were all significantly altered in PT patients. Daily intake of energy and carbohydrate, and serum level of high-density lipoprotein protein were statistically indistinguishable between PT patients and healthy controls.

Conclusion

Chinese girls with PT are potentially insulin resistant, which warrants more clinical attention and further investigation to address the underlying etiology.

Serum nesfatin-1 and leptin levels in non-obese girls with premature thelarche

AIM

We aimed to investigate serum nesfatin-1 level in girls with premature thelarche (PT) and its relationship with anthropometric parameters and leptin, which are involved in the initiation of pubertal process.

SUBJECTS-METHODS

Non-obese girls who presented with the complaint of early (2-8 years) and isolated breast development were included in the study. The control group consisted of age-matched healthy prepubertal girls. Auxological measurements were performed in all subjects. Gonadotropin-releasing hormone (GnRH) stimulation test and bone age assessment were conducted in subjects with early breast development. Girls with a bone age/chronologic age ratio <1.2 and a peak luteinizing hormone (LH) response to GnRH stimulation <5 mIU/L were included in the PT group.

RESULTS

The study included 22 non-obese girls with PT and 24 healthy prepubertal controls. Body mass index (BMI), BMI-standard deviation score (SDS) and height SDS were similar between the groups (p > 0.05). Serum leptin and nesfatin-1 levels were found significantly higher in the PT group compared to controls (p < 0.05). No correlation was detected between nesfatin-1 and basal LH, basal follicle stimulating hormone (FSH), stimulated peak LH, peak FSH, leptin levels and anthropometric parameters in the PT group (p > 0.05).

CONCLUSION

Results of the present study showed that serum nesfatin-1 and leptin levels are significantly higher in girls with PT than in prepubertal controls. This finding suggests that similar to leptin, nesfatin-1 may also have a central or peripheral role in the initiation of pubertal process and may be related to PT pathogenesis.

Plasma kisspeptin levels in girls with premature thelarche

OBJECTIVE

Premature thelarche (PT) is defined as isolated breast development without secondary sex characteristics in girls below the age of eight. We aimed to determine whether the level of kisspeptin, which plays a role in the release of gonadotropins, is associated with PT.

METHODS

The patient group included children with PT aged 3-8 years (n=20) and the control group included healthy children in the same age range (n=20). Height standard deviation scores (HSDSs), bone maturation and growth velocity were evaluated in the two groups. Basal follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), prolactin (PRL), and sex hormone-binding globulin (SHBG) levels were also measured in the two groups by immunochemiluminometric assay (ICMA). A gonadotropin-releasing hormone (GnRH) test was also conducted in the patient group and the peak levels of FSH and LH were determined. Kisspeptin levels were measured using enzyme immunoassay (EIA).

RESULTS

No differences were found between the groups in terms of age, HSDS, annual growth rate and bone age. While the plasma basal FSH, LH and E2 levels in the patient and control groups did not show statistically significant differences, PRL levels were higher in the patient group (p<0.05). Peak LH response to GnRH test was at the prepubertal level (<5 ng/mL) in patients with PT. In the patient group, kisspeptin levels were significantly higher compared to the levels in the control group (2.96 ± 1.21 ng/dL vs. 1.19 ± 0.41 ng/dL, p<0.05), and kisspeptin levels showed a significant correlation with PRL, FSH, LH, and E2 levels (p<0.05).

CONCLUSIONS

In this study, plasma kisspeptin levels were found to be higher in patients with PT and to show a positive correlation with increased PRL levels. Kisspeptin is one of the neuropeptides that plays a role in the onset of puberty. Our results support the hypothesis that PT may result from the temporary activation of central stimulants.

A study of anthropomorphic and biochemical characteristics in girls with central precocious puberty and thelarche variant

BACKGROUND

Premature thelarche in later childhood may progress to central precocious puberty (CPP), which does not spontaneously resolve. Thelarche variant (TV) is a slowly progressive variant of precocious puberty.

AIM

To determine and compare levels of insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3) and anthropomorphic measures in girls with TV and CPP.

SUBJECTS

Prepubertal controls and girls with TV and CPP.

METHODS

Chronological and bone age, weight, height, BMI, height velocity (HV), and serum IGF-I, IGFBP-3, leptin, follicle-stimulating hormone (FSH) and lutenizing hormone (LH) levels were assessed.

RESULTS

Serum IGF-I levels, HV and IGF-I/ IGFBP-3 ratio were significantly higher in girls with CPP compared to both controls and girls with TV. IGFBP-3 values for bone age (IGFBP-3BA) were significantly higher in the TV group compared to both controls and girls with CPP. FSH and LH concentrations were significantly higher in the CPP group compared to TV.

CONCLUSION

HV, IGF-I, LH and FSH levels and IGF-I/IGFBP-3 ratio are elevated in girls with CPP compared to those with TV.

A comparison of patients with premature thelarche and idiopathic true precocious puberty in the initial stage of illness

A comparative study of patients with premature thelarche and patients with idiopathic true precocious puberty was conducted. The age at the first visit tended to be lower for those with precocious puberty. In comparison with normative data for children, the frequency of low birthweight and small for date (SFD) status was greater in the 55 patients with premature thelarche, but SFD was also frequent in the 18 patients with precocious puberty. The height, weight and Kaup's index were all within the normal range for these two groups. The ratios for bone age/chronologic age and bone age/height age tended to be high in both groups. In the patients with premature thelarche, the blood luteinizing hormone (LH) level showed a normal response, and the blood follicle stimulating hormone (FSH) level a hyper-response, to stimulation with luteinizing hormone-releasing hormone (LH-RH). In contrast, both the blood LH and FSH levels showed a normal response to LH-RH stimulation in most of the patients with precocious puberty, and a hyper-response was rare among them. Although the blood estradiol (E2) level was higher in patients with precocious puberty than in those with premature thelarche, about 50% and 90% of the patients in the respective groups had normal levels. These results suggest that normal responses of blood LH and excessive responses of blood FSH to LH-RH loading may be useful in some patients for diagnosing premature thelarche at an early stage.

Premature thelarche: a long-term follow-up

The differentiation between premature thelarche and idiopathic central precocious puberty is essential for both long-term prognosis and therapeutic approach but, until now, there have been insufficient data to predict the future of the girls with premature thelarche. We studied 46 girls with premature thelarche longitudinally. The girls were subdivided into two groups according to the time of onset of thelarche: Group A consisted of 26 girls who presented thelarche before the second year of life (mean +/- SD 14.7 +/- 5.2 months) and Group B contained 20 girls who showed breast enlargement after the second year of life (5.7 +/- 3.1 years). The mean basal follicle-stimulating hormone (FSH) level of the patients as a whole was significantly higher than normal values (2.1 +/- 0.05 vs. 0.7 +/- 0.9 mIU/ml, p < 0.01) and the luteinizing hormone (LH) level was not significantly different from that in healthy control subjects (0.8 +/- 0.6 vs. 0.6 +/- 0.7 mIU/ml). After gonadotropin-releasing hormone test the FSH response was significantly higher than normal prepubertal values (12.9 +/- 2.1 vs. 3.9 +/- 2.9 mIU/ml, p < 0.001) whereas the LH response did not differ significantly (1.8 +/- 0.6 vs. 1.7 +/- 0.9 mIU/ml). After a follow-up time ranging from 5.1 to 7.8 years (mean +/- SD 5.9 +/- 1.9) we observed a greater percentage of disappearance in the girls in Group A than in those in Group B. The present data show that the percentage of girls who developed precocious puberty was significantly higher when they presented thelarche after the age of 2 years than before; the age of onset of thelarche can be useful to distinguish patients at risk of progressing towards precocious puberty.

Progression of premature thelarche to central precocious puberty

To evaluate whether girls with premature thelarche progress to central precocious puberty (CPP) and to analyze their clinical and hormonal characteristics, we retrospectively examined 100 girls with premature thelarche who were followed for several years. Fourteen of the patients with characteristics diagnostic of premature thelarche (isolated breast development before age 8 years, bone age advancement within 2 SD of normal, normal growth velocity, follicle-stimulating hormone-predominant response to luteinizing hormone-releasing hormone) progressed during follow-up to precocious or early central puberty (progressive breast size increase, bone age acceleration, and significant decrease in predicted adult height). The chronologic age of this group of 14 girls was 5.1 +/- 2.0 years at the onset of premature thelarche and 7.8 +/- 0.6 years (mean +/- SD) after progression to central early or precocious puberty. Pelvic ultrasonography showed significant differences in measurements between the time of diagnosis of premature thelarche and progression to CPP. Nine of these patients required treatment, three with cyproterone acetate and six with luteinizing hormone-releasing hormone analogs, and all responded as expected for classic CPP. At baseline evaluation, no clinical or hormonal characteristics could be established that separated the 14 children who progressed to precocious or early puberty from the 86 girls who did not. We conclude that premature thelarche is not always a self-limited condition and may sometimes accelerate the timing of puberty.

Prognostic signs in the evolution of premature thelarche by discriminant analysis

Since premature thelarche (PT) can be a first sign of precocious puberty (PP), the aim of our study was to identify simple items in the course of the first 6 months of follow-up that could help predict if PT would evolve to PP. Thirty-two girls with PT were studied. First evaluation included bone age (BA), basal estradiol, FSH, LH and prolactin. GnRH was performed in 15 subjects and BA was checked at 6 month intervals in 30. Based on clinical outcome after a mean follow-up of 33.4 +/- 16.5 (SD) months, patients were divided into 2 groups: Group I (G-I) included subjects whose breast development either remained unchanged, increased or regressed; Group II (G-II) included subjects who progressed to PP. The multivariate combination of the items which was able to best discriminate between the two groups was chosen in predicting the evolution of PT. The items considered included four variables available at the time of diagnosis [chronological (CA) at onset less than 3 years, basal FSH, basal LH and BA/CA ratio] and two additional variables after a 6-month follow-up (delta BA/delta CA and growth velocity); 88% of G-I and 14% of G-II had CA less than 3 yr. Basal FSH levels were elevated in both G-I (7.6 +/- 3.0 mIU/ml) and G-II (12.1 +/- 4.1) with respect to controls (2.6 +/- 1.2); however, approximately 20% of G-I had low FSH levels. Basal LH levels were consistently higher in G-II (8.0 +/- 1.3 mIU/ml) than in G-I (2.9 +/- 1.5) or controls (2.8 +/- 1.2). Although initial BA was advanced (greater than 2SD) in 21% of G-I and in all of G-II, an acceleration of BA was seen only in G-II. The mean growth velocity of G-I (44.1 +/- 31.5%) was significantly less than G-II (92 +/- 32%; p less than 0.0025). With the help of the discriminant equations derived from data obtained at diagnosis and during the first 6 months of follow-up, all subjects with isolated premature thelarche could be sharply distinguished from those who subsequently progressed to precocious puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

Sex hormone-binding globulin and thyroxine-binding globulin levels in premature thelarche

Premature thelarche is defined as the isolated development of breast tissue in girls less than 8 years of age. Although breast development is an estrogen-dependent process, these girls do not have elevated serum estrogen levels, and the hormonal basis for their condition is unclear. We studied the levels of two estrogen-dependent transport proteins, sex hormone-binding globulin (SHBG) and thyroxine-binding globulin (TBG), in order to determine if there was evidence for a more subtle estrogen effect in girls with premature thelarche. SHBG levels in girls with premature thelarche were not significantly different from those of prepubertal girls of the same ages and were significantly lower than those in girls undergoing pubertal development at the appropriate age (P less than 0.05) and in normal women (P less than 0.001). There was no statistically significant difference in TBG levels between the girls with premature thelarche and prepubertal controls. There was also no significant difference in TBG levels between prepubertal girls and girls in early puberty. In contrast, women had TBG levels that were significantly lower than those in all girls studied. We conclude that the estrogen exposure (whether endogenous or exogenous) of girls with premature thelarche is less than that of girls in early true puberty and similar to that of other prepubertal girls. Further, changes in serum TBG are not as sensitive an indicator of estrogen effect as is breast development or changes in SHBG. This study also suggests that large amounts of exogenous estrogens are not an element in the development of premature thelarche.

Clinical and endocrinologic study of precocious puberty in girls

We describe 30 girls with precocious puberty whom we have seen during the last ten years. Modern procedures such as cerebral computer tomography and abdominal sonography increase diagnostic accuracy so that the incidence of idiopathic precocious puberty is likely to diminish. Abdominal sonography is of value in detecting and monitoring the growth of ovarian cysts and thus exploratory laparotomy can be avoided in those cases in which cysts regress rapidly. A modified classification of precocious is proposed.

Studies of gonadotrophin pulsatility and pelvic ultrasound examinations distinguish between isolated premature thelarche and central precocious puberty

We have studied the pulsatile secretion of gonadotrophins at night and made ovarian ultrasound examinations in three girls with central precocious puberty and three with isolated premature thelarche. The three girls with precocious puberty had well-defined pulsatile secretion of LH and FSH with LH predominating, as would be expected in normal puberty. Pulsatile secretion of gonadotrophins was also seen in girls with premature thelarche but the pattern was reversed. In girls with precocious puberty, large "multicystic" ovaries and large uteri were seen on ultrasound examination, whereas girls with isolated premature thelarche had small uteri and ovaries with less than four "cysts" up to 15 mm in diameter. These data provide the key to understanding the aetiology of isolated premature thelarche.

Precocious breast development: a case of unilateral hyperplasia of the adrenal cortex

The case of a 14-month-old girl presenting with precocious breast development due to adrenal hyperplasia is reported. The endocrine studies revealed a slight elevation of the plasma progesterone, 17 alpha-hydroxyprogesterone, testosterone and oestrone levels, and an increased urinary oestrogen excretion. The findings of the ultrasound examination and the evidence that the oestradiol concentration in the left adrenal vein was higher than in the right adrenal vein confirmed the diagnosis of left adrenal hyperfunction. Surgical exploration revealed unilateral hyperplasia of the adrenal cortex. After adrenalectomy the plasma hormone levels and urinary oestrogen excretion fell to normal, with concomitant regression of breast tissue. The girl shows no signs of recurrence of the disorder in a 2 year follow-up. This adrenal hyperplasia might be a benign adrenal disorder causing precocious breast development.