Follicle-stimulating hormone (FSH) and luteninizing hormone (LH) in the urine of prepubertal children

The Use of Morning Urinary Gonadotropins and Sex Hormones in the Management of Early Puberty in Chinese Girls

CONTEXT

Although gonadotropin-releasing hormone stimulation test (GnRHST) is the gold standard in diagnosing central precocious puberty (CPP), it is invasive, expensive, and time-consuming, requiring multiple blood samples to measure gonadotropin levels.

OBJECTIVE

We evaluated whether urinary hormones could be potential biomarkers for prepuberty or postpuberty, aiming to simplify the current diagnosis and prognosis procedure.

METHODS

We performed a cross-sectional study of a total of 355 girls with CPP in National Clinical Research Center for Child Health in China, including 258 girls with positive and 97 girls with negative results from GnRHST. Twenty patients received GnRH analogue (GnRHa) treatment and completed a 6-month follow up. We measured luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, prolactin, progesterone, testosterone, and human chorionic gonadotropin in the first morning voided urine samples.

RESULTS

Their urinary LH levels and the ratios of LH to FSH increased significantly with the advancement in Tanner stages. uLH levels were positively associated with basal and peak LH levels in the serum after GnRH stimulation. A cutoff value of 1.74 IU/L for uLH reached a sensitivity of 69.4% and a specificity of 75.3% in predicting a positive GnRHST result. For the combined threshold (uLH ≥ 1.74 + uLH-to-uFSH ratio > 0.4), the specificity reached 86.6%. After 3 months of GnRHa therapy, the uLH and uFSH levels decreased accordingly.

CONCLUSION

uLH could be a reliable biomarker for initial CPP diagnosis and screening; uLH could also be an effective marker for evaluating the efficacy of clinical treatment.

Sex Differences in Effects of Obesity on Reproductive Hormones and Glucose Metabolism in Early Puberty

CONTEXT

Obesity is known to impact reproductive function in adults, but little is known about its effects on reproductive hormones during puberty.

OBJECTIVE

To assess sex differences in effects of obesity on reproductive hormones and their relation to insulin sensitivity and secretion.

DESIGN

Cross-sectional study including anthropometrics, serum and urine reproductive hormone concentrations, and intravenous glucose tolerance testing (IVGTT) to assess acute insulin response to glucose (AIRg), and insulin sensitivity (Si).

SETTING

Outpatient academic clinical research center.

PATIENTS

Girls (52%) and boys (48%) who were normal weight (NW; n = 51, BMI-Z score = -0.11 ± 0.77, age = 11.5 ± 1.7 years) and obese (n = 53, BMI-Z score = 2.22 ± 0.33, age = 10.9 ± 1.5 years), Tanner stage 2 to 3.

RESULTS

Boys with obesity had lower total testosterone (P < 0.0001) and higher concentrations of the urinary estradiol metabolite, E1c, (P = 0.046) than boys with NW. Girls with obesity had higher free androgen index (FAI; P = 0.03) than NW girls. Both boys and girls with obesity had lower sex hormone-binding globulin (SHBG; P < 0.0001) than NW. AIRg was inversely related to SHBG in boys (R = 0.6, P < 0.0001) and girls (R = 0.53, P = 0.0001). Si correlated with higher SHBG in boys (R2 = 0.67, P < 0.0001) and girls (R = 0.5, P = 0.0003), higher total testosterone for boys (R = 0.39, P = 0.01), and lower FAI for girls (R = -0.2, P = 0.04).

CONCLUSION

Youth with obesity have lower SHBG than youth with NW, but obesity has differential effects on reproductive hormones in girls versus boys, which are apparent early in puberty. Ongoing longitudinal studies will evaluate the impact of obesity on reproductive hormones in girls and boys as puberty progresses.

Sexual maturity in western Atlantic bluefin tuna

We introduce a novel endocrine approach for assessing the unresolved matter of the timing of sexual maturation in western Atlantic bluefin tuna (ABFT), a highly migratory population whose status remains uncertain. Ratios of follicle stimulating hormone to luteinizing hormone, a sexual maturity indicator, in all ABFT ≥134 cm curved fork length (CFL) were <0.4, similar to Mediterranean spawners, indicating that western ABFT mature at considerably smaller sizes and at a much younger age than currently assumed (≥185 cm CFL).

Intra-pituitary relationship of follicle stimulating hormone and luteinizing hormone during pubertal development in Atlantic bluefin tuna (Thunnus thynnus)

As part of the endeavor aiming at the domestication of Atlantic bluefin tuna (BFT; Thunnus thynnus), first sexual maturity in captivity was studied by documenting its occurrence and by characterizing the key hormones of the reproductive axis: follicle stimulating hormone (FSH) and luteinizing hormone (LH). The full length sequence encoding for the related hormone β-subunits, bftFSHβ and bftLHβ, were determined, revealing two bftFSHβ mRNA variants, differing in their 5' untranslated region. A quantitative immuno-dot-blot assay to measure pituitary FSH content in BFT was developed and validated enabling, for the first time in this species, data sets for both LH and FSH to be compared. The expression and accumulation patterns of LH in the pituitary showed a steady increase of this hormone, concomitant with fish age, reaching higher levels in adult females compared to males of the same age class. Conversely, the pituitary FSH levels were elevated only in 2Y and adult fish. The pituitary FSH to LH ratio was consistently higher (>1) in immature than in maturing or pubertal fish, resembling the situation in mammals. Nevertheless, the results suggest that a rise in the LH storage level above a minimum threshold may be an indicator of the onset of puberty in BFT females. The higher pituitary LH levels in adult females over males may further support this notion. In contrast three year-old (3Y) males were pubertal while cognate females were still immature. However, it is not yet clear whether the advanced puberty in the 3Y males was a general feature typifying wild BFT populations or was induced by the culture conditions. Future studies testing the effects of captivity and hormonal treatments on precocious maturity may allow for improved handling of this species in a controlled environment which would lead to more cost-efficient farming.

Comparison of detection of normal puberty in boys by a hormonal sleep test and a gonadotropin-releasing hormone agonist test

CONTEXT

The magnitude of sleep-related gonadotropin rise required to activate pubertal gonadal function is not established.

OBJECTIVE

Our objective was to determine the normal relationship between sleep-related pubertal hormone levels and pituitary-testicular responsiveness to a GnRH agonist (GnRHag) test across the pubertal transition. DESIGN/SETTING AND PARTICIPANTS: We conducted a prospective study in a General Clinical Research Center with healthy 9- to 15-yr-old volunteer boys.

INTERVENTIONS

INTERVENTIONS included overnight blood sampling followed by leuprolide acetate injection (10 μg/kg).

PRIMARY OUTCOME VARIABLES

LH, FSH, and testosterone levels were evaluated.

RESULTS

LH levels during sleep and post-GnRHag rose steadily during the late prepubertal years. Sleep peak LH correlated highly with the LH response to GnRHag across groups (r = 0.913). A sleep peak LH level of at least 3.7 U/liter predicted pubertal testicular activation with 100% accuracy. LH of at least 14.8 and at least 19.0 U/liter 4 h after GnRHag, respectively, predicted puberty with 100% sensitivity/94% specificity and 100% specificity/94% sensitivity. Overweight pubertal boys had transiently prolonged responses to GnRHag. FSH rose during both waking and sleeping hours during the prepubertal years, and all pubertal boys had an FSH level of at least 0.9 U/liter awake and at least 1.2 U/liter asleep. Sleep LH was more closely related than FSH to testicular size.

CONCLUSIONS

These data suggest that a critical LH level during sleep (≥3.7 U/liter) heralds the onset of pubertal virilization and that this level is predictable by LH of at least 14.8-19 U/liter 4 h after GnRHag. These data also suggest that LH stimulation of testicular androgen production plays a role in stimulating testicular tubule growth once a critical level of FSH is achieved.

Urinary gonadotrophins: a useful non-invasive marker of activation of the hypothalamic pituitary-gonadal axis

Background

Non-invasive screening investigations are rarely used for assessing the activation and progression of the hypothalamic-pituitary gonadal axis through puberty. This study aimed to establish a normal range for urinary gonadotrophins in children progressing through puberty.

Methods

Urine samples were collected from 161 healthy school children (76 boys, 85 girls) aged 4–19 yrs. Height and weight were converted to standard deviation score. Pubertal status, classified by Tanner staging, was determined by self-assessment. Urinary gonadotrophins were measured by chemiluminescent microparticle immunoassay. Results were grouped according to pubertal status (pre-pubertal or pubertal).

Results

Of the 161 children, 50 were pre-pubertal (28 boys; 22 girls) and 111 were pubertal (48 boys; 63 girls). Overall, urinary gonadotrophins concentrations increased with pubertal maturation. All pre-pubertal children had a low urinary LH:Creatinine ratio. LH:Creatinine ratios were significantly higher in pubertal compared to pre-pubertal boys (p<0.001). In girls, FSH:Creatinine ratios were significantly higher in the pubertal group (p = 0.006). However, LH:FSH ratios were a more consistent discriminant between pre-pubertal and pubertal states in both sexes (Boys 0.45 pubertal vs 0.1 pre-pubertal; girls 0.23 pubertal vs 0.06 pre-pubertal).

Conclusion

Urinary gonadotrophins analyses could be used as non-invasive integrated measurement of pubertal status which reflects clinical/physical status.

Differentiation of the mammary gland and susceptibility to carcinogenesis

It has been demonstrated that in humans certain factors such as early menarche, late pregnancy, and nulliparity are associated with a higher risk of developing breast cancer, while early pregnancy acts as a protective factor. Induction of mammary cancer in rats by administration of the chemical carcinogen 7,12-dimethylbenz(a)anthracene reveals that the same factors influencing human breast cancer risk also affect the susceptibility of the rat mammary gland to the chemical carcinogen. Nulliparous rats and rats undergoing pregnancy interruption are more susceptible to developing carcinomas. This fact has been attributed to the incomplete differentiation of the gland at the time of carcinogen administration. Parous rats are resistant to the carcinogenic effect of DMBA, which is explained by the complete development of the gland attained during pregnancy and lactation. This development is manifested by the differentiation of terminal end buds into secretory units, which have a smaller proliferative compartment; the epithelial cells of these secretory units have a longer cell cycle, less avidity for binding DMBA, and possess a more efficient DNA excision repair capacity.

Hormonal mechanisms in the onset of puberty

Sexual maturation is associated with increasing levels of sex steroids. These steroidal events are the result of complex changes that occur at several functional levels including the hypothalamus, pituitary, gonad and adrenal gland. These changes, as outlined in Table 3, are often interrelated.

While considerable progress has been made in our understanding of the hormonal events associated with sexual maturation, many important questions remain unanswered. Further intensive investigation will be required before we have a lucid understanding of the physiological basis of the sequence of hormonal events which occur during the pubertal process.

Correlated changes in the structure of the anterior pituitary gland, testes and interrenal tissue during sexual maturation of male lizards

The anterior pituitary gland, testes and interrenal glands of a series of young males of the teiid Cnemidophorus l. lemniscatus (L.) have been studied by light microscopy in order to correlate the changes occurring during sexual maturation. In the testes of the smallest animals, spermatogenesis does not progress beyond primary spermatocytes and there is no differentiated interstitial tissue. In medium-sized animals, spermatids and some interstital cells appear, and in the largest lizards, spermatogenesis is completely established and Leydig cells abound. Simultaneously with the development of the testes, interrenal glands undergo great hypertrophy and hyperplasia, especially in the peripheral reactive zone. Starting in animals of intermediate size, the anterior hypophysis exhibits a considerable hypertrophy of two rostral cell types: the chromophobic corticotrophs and the acidophilic PAS-positive cells considered to be interstitiotrophs, These cells show large, vesicular nuclei and prominent nucleoli, signs of enhanced cellular activity. The hypertrophy begins in the dorso-rostral region of the gland close to the median eminence, at the site of entry of the portal vessels. This suggests a hypothalamic influence on the function of these pars distalis cells. The scattered basophilic gonadotrophs or folliculotrophs are scarce, small, and do not vary appreciably among the animals studied. The hyperactivity of corticotrophs may account for enlargement of the interrenal glands. Testicular development is apparently related to an increased activity of interstitiotrophs but to a stable level of activity in folliculotrophs.

Human puberty. Simultaneous augmented secretion of luteinizing hormone and testosterone during sleep

Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in nine pubertal boys and three sexually mature young men at 20-min intervals for 24 h. Plasma LH and T were also measured in one boy during a delayed sleep onset study. Polygraphic monitoring was carried out to identify precisely sleep onset. Wakefulness, and specific sleep stages. In all nine pubertal boys the plasma T concentration fluctuated and was significantly higher during normal nocturnal sleep as compared to daytime waking. This increased T secretion during sleep was temporally linked to the characteristic pubertal sleep augmentation of LH secretion. To define further the relationship of this increased T secretion to sleep, plasma LH and T were also measured in three of the pubertal boys after acute (1-day) reversal of the sleep-wake cycle. One of these boys was also studied after 3 days of sleep-wake cycle reversal. The results of these studies showed that plasma T was now augmented during the reversed daytime sleep period; the mean T concentrations during this period were significantly higher (P < 0.001) than during nocturnal waking in all four studies. Measurement of plasma LH and T in the three sexually mature young men showed episodic secretion of LH and T during both waking and sleep periods; there was no consistent significant augmentation of LH or T secretion during sleep. This study demonstrates that (a) in normal pubertal boys and sexually mature young men plasma T fluctuates episodically; (b) there is marked augmentation of T secretion during sleep in pubertal boys, which is dependent on increased LH secretion; (c) this pubertal LH-T secretory "program" is dependent on sleep, since it shifts with delayed sleep onset and reversal of the sleep-wake cycle; and (d) this demonstrable tropic effect of LH on T is evident only during puberty, since sexually mature young men fail to show any consistent relationship between LH and T secretion either awake or asleep.

Pituitary-testicular responsiveness in male hypogonadotropic hypogonadism

An isolated deficiency of pituitary gonadotropins was demonstrated in six 46 XY males, 22 to 36 years of age, with and without anosmia. Undetectable or low levels of serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) clearly separated hypogonadotropic from normal adult males. Chronic (8-12 wk) administration of clomiphene citrate caused no increase in serum FSH or LH in gonadotropin-deficient subjects. However, the administration of synthetic luteinizing hormone releasing factor (LRF) resulted in the appearance of serum LH and, to a lesser degree, serum FSH in three subjects tested. While levels of plasma testosterone were significantly lower in gonadotropin-deficient subjects, plasma androstenedione and dehydroepiandrosterone were in a range similar to that of age-matched normal men. Treatment with human chorionic gonadotropin (HCG) increased levels of plasma testosterone to normal adult male values in all gonadotropin-deficient subjects. Cessation of treatment with HCG resulted in the return of plasma testosterone to low, pretreatment levels. That HCG therapy with resultant normal levels of plasma testosterone may somehow stimulate endogenous gonadotropin secretion in gonadotropin-deficient subjects was not evident. The adult male levels of serum FSH and LH after LRF, and plasma testosterone after HCG, confirm pituitary and Leydig cell responsiveness in these subjects.

Suppression of urinary and plasma follicle-stimulating hormone by exogenous estrogens in prepubertal and pubertal children

Clomiphene citrate, an "anti-estrogen" with mild estrogenic properties, inhibits rather than stimulates gonadotropin excretion in prepubertal and early pubertal children. These and other data suggest that the sensitivity of the hypothalamic-pituitary "gonadostat" decreases at the onset of puberty. To test this hypothesis further, the daily excretion of urinary follicle-stimulating hormone (FSH) and luteinizing hormone (LH) was determined in 19 children (5 "short normals" and 14 with isolated human growth hormone (HGH) deficiency) who were given ethinyl estradiol (EE) 1.4-14.7 mug/m(2) per day (2-10 mug/day) for 4 to 7 days. In addition, plasma and urinary gonadotropins and plasma estrogens were serially determined in two prepubertal females(with isolated HGH deficiency) given two injections (24 h apart) of estradiol benzoate, 10 mug/kg. FSH and LH concentrations in plasma and kaolin-acetone urinary concentrates and plasma 17beta-estradiol (E(2)) and estrone (E(1)) were measured by radioimmunoassays. 2-3 mug/m(2) per day of EE significantly suppressed urinary FSH (and LH when detected in the control period) in two out of six prepubertal children, while all doses >5 mug/m(2) per day suppressed urinary gonadotropins to undetectable levels in eight prepubertal subjects. In early to midpubertal subjects. 2-10 mug/m(2) per day of EE produced a slight suppression of urinary FSH, but failed to suppress to undetectable levels. Two subjects in late puberty (stage 4) did not suppress their urinary FSH while on 7 and 8.3 mug/m(2) per day. In both subjects treated with estradiol benzoate, plasma FSH promptly decreased after the first injection. Urinary FSH was suppressed to <0.1 IU/day on day 2 and urinary and plasma gonadotropins remained suppressed for the duration of the study (3 days). Plasma E(2) and E(1) rose from prepubertal values to peak concentrations of 150 to 250 pg/ml (E(2)), and 50 and 100 pg/ml (E(1)) at approximately 36 h. We conclude that the hypothalamic-pituitary-gonadal axis is operative in the prepubertal child and that the sensitivity of the hypothalamic-pituitary center(s) which control the secretion of FSH and LH decreases at the onset of puberty in man.

Output of luteinizing hormone in the urine of normal children and those with advanced sexual development

Estimations by radioimmunoassay of the 24-hour excretion of LH in normal children (152 boys and 104 girls) have shown high values in the first six months of life in boys, and possibly girls, and then low levels until the age of about 6 years. There is then a gradual rise in LH excretion in both sexes which continues for the 3-4 years which precede the onset of puberty, at which age a more marked increase occurs. 13 cases of true precocious puberty were all found to be associated with increased urinary excretion of LH, a feature that was seldom shown with other forms of advanced sexual development. Measurement of urinary LH excretion provides a useful tool in the differentiation of such conditions.

Changing sensitivity of the pubertal gonadal hypothalamic feedback mechanism in man

Clomiphene citrate in doses which stimulate gonadotropin production in the adult suppresses urinary follicle stimulating hormone (FSH) excretion and plasma testosterone concentration in prepubertal children. Such results indicate that feedback between gonad and hypothalamus is operative and highly sensitive in prepubertal humans. Puberty in man, as in the rat, is accompanied by a decrease in the sensitivity of the feedback mechanism.

Studies of the pituitary-Leydig cell axis in young men with hypogonadotropic hypogonadism and hyposmia: comparison with normal men, prepuberal boys, and hypopituitary patients

Pituitary and gonadal function was studied in seven chromatin-negative men, ages 15-27 yr, with retarded sexual and somatic development, skeletal anomalies, and hyposmia. These hyposmic patients were compared with normal men, prepuberal boys and hypogonadal patients with hypopituitarism. The urinary follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels of hyposmic subjects were the same as those of normal boys and hypopituitary patients but significantly lower than those of normal men. Clomiphene citrate did not cause an increase in plasma FSH and LH levels in either hypogonadal group as it does in normal men. In contrast to hypopituitary patients, thyroid and adrenocortical function and release of growth hormone in the hyposmic subjects were normal. The plasma testosterone levels were equally low in prepuberal, hypopituitary, and hyposmic patients but were increased to a greater extent by human chorionic gonadotropin (HCG) treatment in prepuberal and hypopituitary subjects than in the hyposmic patients. Prolonged treatment with HCG has failed to return plasma testosterone levels to normal in two hyposmic patients. These observations suggest that there are defects of both pituitary and Leydig cell function in men with the syndrome of hypogonadism, skeletal anomalies, and hyposmia. They have impaired secretion of FSH and LH and a Leydig cell insensitivity to gonadotropin.