An assessment of the antibacterial activity in larval excretion/secretion of four species of insects recorded in association with corpses, using Lucilia sericata Meigen as the marker species.

The relative antibacterial activities of excretion/secretion (ES) from two carrion-feeding insects, Calliphora vicina Robineau-Desvoidy and Dermestes maculatus DeGeer, and a detritivore, Tenebrio molitor Linnaeus, were compared to that of Lucilia sericata Meigen, a species with ES of known antibacterial capacity, in order to explore the antimicrobial potential of other carrion and detritivore species. Viable counts were used to assess time-kill of ES against five bacterial species, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa and Proteus mirabilis. Antibacterial activity was recorded in all four insect species although T. molitor and D. maculatus were the most effective in controlling growth of P. mirabilis. The blowflies were more effective in controlling a wider range of both Gram-positive and Gram-negative bacteria. The larval ES from all species was shown to reduce bacterial growth rate although differences in antibacterial spectrum were noted and the degree of potency varied between the four species. These differences may be explained ecologically by the different colonisation times of each insect species on the corpse. Overall, this study demonstrates that research into other carrion-feeding insect species has potential to provide an increased source of antimicrobial chemicals to broaden the range of bacterial species beyond that currently controlled using L. sericata.

Role of resistin in insulin sensitivity in rodents and humans.

Resistin is a potential link between obesity and insulin resistance or type 2 diabetes. In rodents, resistin is primarily expressed in and secreted from mature adipocytes, with some expression in pancreatic islets and portions of the pituitary and hypothalamus. Its secretion can be up-regulated by several factors, including insulin and glucose. The exposure of rodents, or their cells, to resistin results in decreased response to insulin. This is likely in part due to an up-regulation of suppressor of cytokine signaling (SOCS)-3, which interferes with the activation of insulin receptor substrate (IRS)-1. However, in humans resistin is expressed primarily by macrophages and seems to be involved in the recruitment of other immune cells and the secretion of pro-inflammatory factors, including tumor necrosis factor (TNF)alpha. Human resistin may interfere with insulin signaling by stimulating the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN), which dephosphorylates 3-phosphorylated phosphoinositide (PIP(3)). Resistin also seems to be involved in the development of atherosclerosis in humans by promoting the formation of foam cells and the proliferation and migration of vascular endothelial and smooth muscle cells. Many of the inflammatory related functions of human resistin appear to be regulated by activation of the nuclear factor (NF)kappaB transcription factor. The divergent roles of resistin in humans and rodents are evident by the data presented in this review but they will not be able to be fully understood until the resistin receptor is identified.

Spatial and temporal regulation of GH-IGF-related gene expression in growth plate cartilage.

Previous studies of the GH-IGF system gene expression in growth plate using immunohistochemistry and in situ hybridization have yielded conflicting results. We therefore studied the spatial and temporal patterns of mRNA expression of the GH-IGF system in the rat proximal tibial growth plate quantitatively. Growth plates were microdissected into individual zones. RNA was extracted, reverse transcribed and analyzed by real-time PCR. In 1-week-old animals, IGF-I mRNA expression was minimal in growth plate compared with perichondrium, metaphyseal bone, muscle, and liver (70-, 130-, 215-, and 400-fold less). In contrast, IGF-II mRNA was expressed at higher levels than in bone and liver (65- and 2-fold). IGF-II expression was higher in the proliferative and resting zones compared with the hypertrophic zone (P < 0.001). GH receptor and type 1 and 2 IGF receptors were expressed throughout the growth plate. Expression of IGF-binding proteins (IGFBPs)-1 through -6 mRNA was low throughout the growth plate compared with perichondrium and bone. With increasing age (3-, 6-, 9-, and 12-week castrated rats), IGF-I mRNA levels increased in the proliferative zone (PZ) but remained at least tenfold lower than levels in perichondrium and bone. IGF-II mRNA decreased dramatically in PZ (780-fold; P < 0.001) whereas, type 2 IGF receptor and IGFBP-1, IGFBP-2, IGFBP-3, and IGFBP-4 increased significantly with age in growth plate and/or surrounding perichondrium and bone. These data suggest that IGF-I protein in the growth plate is not produced primarily by the chondrocytes themselves. Instead, it derives from surrounding perichondrium and bone. In addition, the decrease in growth velocity that occurs with age may be caused, in part, by decreasing expression of IGF-II and increasing expression of type 2 IGF receptor and multiple IGFBPs.

Regulation of growth plate chondrogenesis by bone morphogenetic protein-2.

Bone morphogenetic proteins (BMPs) regulate embryonic skeletal development. We hypothesized that BMP-2, which is expressed in the growth plate, also regulates growth plate chondrogenesis and longitudinal bone growth. To test this hypothesis, fetal rat metatarsal bones were cultured for 3 days in the presence of recombinant human BMP-2. The addition of BMP-2 caused a concentration-dependent acceleration of metatarsal longitudinal growth. As the rate of longitudinal bone growth depends primarily on the rate of growth plate chondrogenesis, we studied each of its three major components. BMP-2 stimulated chondrocyte proliferation in the epiphyseal zone of the growth plate, as assessed by [(3)H]thymidine incorporation. BMP-2 also caused an increase in chondrocyte hypertrophy, as assessed by quantitative histology and enzyme histochemistry. A stimulatory effect on cartilage matrix synthesis, assessed by (35)SO(4) incorporation into glycosaminoglycans, was produced only by the highest concentration of BMP-2. These BMP-2-mediated stimulatory effects were reversed by recombinant human Noggin, a glycoprotein that blocks BMP-2 action. In the absence of exogenous BMP-2, Noggin inhibited metatarsal longitudinal growth, chondrocyte proliferation, and chondrocyte hypertrophy, which suggests that endogenous BMPs stimulate longitudinal bone growth and chondrogenesis. We conclude that BMP-2 accelerates longitudinal bone growth by stimulating growth plate chondrocyte proliferation and chondrocyte hypertrophy.

Effect of gonadotropin secretion rate on the radiosensitivity of the rat luteinizing hormone-releasing hormone neuron and gonadotroph.

To test the hypothesis that the functional state of hypothalamic LHRH neurons and pituitary gonadotrophs might alter their radiosensitivity, we determined the experimental conditions under which the gonadotropin response to castration could be impaired by a single dose of cranial irradiation. Single doses of cranial irradiation greater than 2000 rads were lethal to unshielded rats. Shielding of the oropharynx and esophagus allowed the animals to survive doses up to 5000 rads. Doses between 2000 and 5000 rads had no effect on basal gonadotropin levels for as long as 3 months after irradiation. Irradiation caused a dose- and time-dependent impairment, however, in the gonadotropin response to castration. Impairment of the gonadotropin levels of castrate animals occurred in animals that were irradiated either before or after castration. However, rats irradiated in the castrate state showed a decreased susceptibility to irradiation damage. Additionally, stimulation of the pituitary by LHRH agonist (LHRHa) 3 h before irradiation significantly reduced the impairment of gonadotropin secretion 12-20 weeks after irradiation (P less than 0.05). Thus, increased functional activity of the rat hypothalamus or pituitary at the time of irradiation, induced by either castration or acute LHRHa administration, was associated with some protection against the gonadotropin-lowering effect of irradiation. Based upon these data, we hypothesize that stimulation of gonadotropin secretion at the time of therapeutic cranial irradiation in humans might protect against subsequent impairment of gonadotropin secretion.

Retinoic acid is a potent regulator of growth plate chondrogenesis.

Vitamin A deficiency and excess both cause abnormalities in mammalian longitudinal bone growth. Because all-trans retinoic acid (RA) is synthesized from vitamin A, we hypothesized that RA regulates growth plate chondrogenesis. Consistent with this hypothesis, a single oral dose of RA reduced the height of the rat proximal tibial growth plate. To determine whether RA acts directly on growth plate, fetal rat metatarsal bones were cultured in the presence of RA. In this system, RA inhibited longitudinal bone growth by three mechanisms: 1) decreased chondrocyte proliferation, (assessed by 3H-thymidine incorporation), particularly in the proliferative zone of the growth plate; 2) decreased matrix synthesis (assessed by 35SO4 incorporation into glycosaminoglycans); and 3) decreased cell hypertrophy (determined histologically). The growth-inhibiting effects of RA were completely reversed by a retinoic acid receptor (RAR) antagonist. In the absence of exogenous RA, this antagonist accelerated bone growth, as did an RA-specific neutralizing antibody, suggesting that endogenous RA negatively regulates growth plate chondrogenesis. We conclude that RA, acting through RARs, negatively regulates longitudinal bone growth by inhibiting growth plate chondrocyte proliferation, chondrocyte hypertrophy, and matrix synthesis.

Treatment of familial male precocious puberty with spironolactone, testolactone, and deslorelin.

Combined antiandrogen (spironolactone) and aromatase inhibitor (testolactone) are effective for the short term treatment of familial male precocious puberty. During this therapy, plasma testosterone levels remain in the adult range, since spironolactone blocks the testosterone receptor without significantly affecting plasma testosterone levels. After our initial 18-month pilot study, we continued to treat eight boys with the combined therapy for 2.0-4.2 yr. During this time all boys exhibited a pubertal rise in gonadotropin secretion and a diminishing response to treatment, which was manifested by the recurrence of clinical features of puberty and an increase in the bone maturation rate (P < 0.05). Addition of the LHRH agonist deslorelin (4 micrograms/kg.day, sc) to the combined therapy decreased peak LH, plasma testosterone, bone maturation rate, and growth velocity (P < 0.05) over the next year. We conclude that the rise in gonadotropin levels during central activation of hypothalamic LHRH secretion in boys with familial male precocious puberty causes a partial escape from the combined effect of spironolactone and testolactone. The addition of deslorelin to the combined therapy appears to restore the control of puberty in this setting.

Effect of deslorelin dose in the treatment of central precocious puberty.

Central precocious puberty is effectively treated with long-acting LHRH analogs (LHRHas). Although at least six LHRHas have now been used in children, there have been no studies to determine the least effective dose of any of these analogs. We sought to determine the effect of decreasing an efficacious dose of deslorelin (D-Trp6-Pro9-NEt-LHRH) on basal and LHRH-stimulated gonadotropins, estradiol levels, and the rates of linear growth and skeletal maturation in subjects with central precocious puberty. Twenty-nine children with central precocious puberty were enrolled in a double blinded study. All subjects were treated for the initial 3 months with deslorelin at a dose (4 micrograms/kg.day, sc) known to suppress gonadotropins, linear growth velocity, and the rate of skeletal maturation. After 3 months, the subjects were randomly assigned to receive one of three daily sc doses of deslorelin: 4 micrograms/kg (n = 9), 2 micrograms/kg (n = 11), or 1 micrograms/kg (n = 9). They were treated at this dose in double blinded fashion for 15 months, after which time they resumed therapy at a dose of 4 micrograms/kg.day for an additional year. The children in the three groups did not differ in terms of chronological age, bone age, pretreatment growth rate, or Tanner stage at the onset of therapy. Similarly, there were no differences in the clinical and hormonal responses to the first 3 months of LHRHa therapy (4 micrograms/kg.day). During the 15-month period at the three different doses, the three dose groups could not be distinguished from each other in terms of pubertal stage, linear growth velocity, rate of skeletal maturation, sex steroid levels, mean LH or FSH levels, or peak FSH response to LHRH stimulation or to a dose of deslorelin. In contrast, the peak LH response to LHRH stimulation was highest in children treated with the lowest dose (1 micrograms/kg.day; P less than 0.025, by multiple analysis of variance). In addition, the peak LH response to a dose of deslorelin (the LHRHa test) was higher in children treated with 1 micrograms/kg.day than in those treated with 4 micrograms/kg.day (P less than 0.04). In summary, the LHRHa test is a sensitive means for detecting activation of the hypothalamic-pituitary-gonadal axis, and deslorelin at a dose of 1 micrograms/kg.day results in less gonadotropin suppression than a dose of 4 micrograms/kg.day.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin-like growth factor I (IGF-I) and IGF-binding protein-3 concentrations compared to stimulated and night growth hormone in the evaluation of short children--a clinical research center study.

To evaluate the relative usefulness of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) in screening for GH status, GH stimulation (arginine-insulin/L-DOPA) tests and overnight GH studies (every 20 min sampling) were performed in 104 healthy short children (32 girls), aged 3-16 yr (height, -1.8 or more SD). IGFBP-3 had no advantage over IGF-I in screening sensitivity or specificity. IGF-I correlated with mean nighttime GH. Both IGF-I and IGFBP-3 correlated with peak stimulated GH. To identify more than 90% of children with GH deficiency (GHD) and borderline GHD, the mean values for age for IGF-I and IGFBP-3 were required as the cut-off criterion. However, at this criterion, 70% or more of idiopathic short stature (ISS) children would have to undergo testing to identify 90% of GHD or borderline GHD. More stringent criteria (-1.0, -1.64, and -2.0 SD) were more specific, but lost sensitivity. A practical application is suggested. Screening use of IGF-I with criterion of -1.0 SD would identify a subgroup that includes 88% of GHD, 71% of borderline GHD, and 46% of ISS. Both IGF-I and IGF-BP-3 higher than -1.0 SD would accurately identify 68% of ISS as not needing GH testing. Evaluation of growth velocity would identify the remaining children requiring definitive testing. Thus, combined screening for GHD using both IGF-I and IGFBP-3 has no better sensitivity than either test alone. However, such combined screening will improve the specificity and thus decrease the number of normal but short children who might otherwise undergo unnecessary testing.

Overnight growth hormone concentrations are usually normal in pubertal children with idiopathic short stature--a Clinical Research Center study.

To estimate the incidence of low growth hormone (GH) concentration in children and adolescents with idiopathic short stature, overnight GH levels were measured in 167 subjects. The results were compared with data from 132 normal children of similar pubertal stage, bone age, or body mass index. The majority of short children had normal overnight GH concentrations in a distribution not significantly different from that observed in normal children. However, in 6% of children grouped by pubertal stage and in 13% of children grouped by bone age, overnight GH levels were below the 95% confidence limits of normal. The overnight GH levels were above normal in 6%. The observed frequencies of both low and high GH levels were significantly greater than expected (P < 0.001). However, when body mass index was included in the analysis, only 5% of the children had low GH measures, and only 4% had high GH measures (both not significant). This frequency of low overnight GH levels in short children is considerably less than that reported by others. Thus, these data do not support the hypothesis that a deficiency of spontaneous GH secretion is a common cause of short stature. We conclude that standard GH stimulation tests, despite their limitations, remain the best definitive test of GH secretion. Subsequent overnight GH studies may be useful, however, in selected clinical settings such as previous cranial irradiation or other central nervous system disorder.

Two-year comparison of testicular responses to pulsatile gonadotropin-releasing hormone and exogenous gonadotropins from the inception of therapy in men with isolated hypogonadotropic hypogonadism.

Men with the complete form of isolated hypogonadotropic hypogonadism (initial mean testes volume less than 4 mL) require 2 or more yr of exogenous gonadotropin therapy combining hCG and human menopausal gonadotropin (hMG) to achieve maximal, but subnormal, testis size and sperm output. To test whether pulsatile GnRH therapy, which more closely mimics normal hormonal stimulation, would accelerate or further augment testicular growth, hasten the onset of sperm production, and/or increase sperm output more than occurs during conventional exogenous gonadotropin therapy, we administered either hCG/hMG or GnRH from the inception of therapy to 2 comparable groups of men with complete IHH (initial testicular volume, less than 4 mL) and compared their testicular responses during the first 2 hr of therapy. Five men were treated with pulsatile GnRH in doses of 143-714 ng/kg every 2 h, sc, while 11 other men received hCG (2000 IU) and hMG (75 IU FSH and 75 IU LH) im 3 times/week. In the GnRH-treated men, the mean plasma total and free testosterone levels during therapy rose to within the normal range, but were significantly lower (P less than 0.01 and P less than 0.02, respectively) than those in the hCG/hMG-treated men. The mean plasma estradiol concentrations during therapy were within the high normal range and were similar in the two groups. The mean plasma FSH levels achieved in the GnRH-treated men were significantly (P less than 0.01) and 1.3- to 3.2-fold higher than those in the hCG/hMG-treated men. The mean testicular size achieved in the GnRH-treated men was not significantly different from that in the hCG/hMG-treated men (P = 0.08); the mean testicular volumes after 2 yr were 4.8- and 4.3-fold the pretreatment values in the GnRH and hCG/hMG groups, respectively. After 12 months of therapy, sperm production had occurred in one man in the GnRH group and in no subject in the hCG/hMG group. After 24 months, two men in the GnRH group and eight men in the hCG/hMG group produced sperm. Thus, 40% of the GnRH-treated men and 80% of the hCG/hMG-treated men (P = NS) produced sperm after 2 yr of therapy. The sperm concentrations in all men were below 5 million/mL and were comparable in the two groups (P = NS). These results suggest that pulsatile sc GnRH therapy for the first 2 yr does not accelerate or enhance testicular growth, hasten the onset of sperm production, or increase sperm output significantly compared to hCG/hMG.

Adult height in precocious puberty after long-term treatment with deslorelin.

Precocious puberty often leads to short adult height. Since the introduction of luteinizing hormone-releasing hormone (LHRH) agonist treatment for LHRH-dependent precocious hormone (LHRH) agonist treatment for LHRH-dependent precocious puberty in 1979, several reports have shown increased predicted height among LHRH agonist-treated children. To determine whether the LHRH agonist deslorelin can normalize the adult height of children with precocious puberty, we are conducting a long-term pilot study involving 161 children. This report describes the first 44 children to have attained final or proximate adult height. These children were 7.1 +/- 1.2 (mean +/- SD) yr old (bone age 11.8 +/- 1.5 yr) and had been in puberty for 3.1 +/- 0.3 yr at the start of treatment. They were treated with deslorelin (4 micrograms/kg/day sc) for 4.1 +/- 1.3 yr and had been withdrawn from treatment for an average of 2.4 yr at the time of this study (age 13.6 +/- 0.9 yr). Fourteen of the 44 children, who had grown less than 0.5 cm during the previous year, were considered to have attained adult height. The other 30 children had achieved 98.6% of predicted mature height (Bayley-Pinneau method) and were considered to be at proximate adult height. The final or proximate adult height of these 44 children averaged -1.1 SD compared to the adult height of the normal population. This height was significantly greater than the pretreatment height (-1.1 vs. -2.0 SD, P less than 0.01), but significantly less than both the predicted height at the end of treatment (-1.1 vs. -0.5 SD, P less than 0.01) and the target height derived from the mean height of the parents adjusted for the sex of the child (-1.1 vs. 0.1 SD, P less than 0.01). The observation that the Bayley-Pinneau height prediction at the end of treatment overestimated the actual adult height emphasizes the importance of using final height data to assess the ultimate impact of LHRH agonist treatment. It also indicates the need for caution when predicting the adult height of children who are still receiving treatment. We conclude that deslorelin has improved the adult height of these patients but has not fully restored height to the patients' genetic potential. We hypothesize that further improvement will be seen in patients who are treated with less delay and at a younger bone age.

Six-year results of spironolactone and testolactone treatment of familial male-limited precocious puberty with addition of deslorelin after central puberty onset.

Short term treatment with spironolactone, testolactone, and, after the onset of central puberty, deslorelin can normalize the rate of growth and bone maturation in boys with familial male-limited precocious puberty. To test the hypothesis that this treatment can achieve long term normalization of the growth and development of these children, we examined the growth rate, bone maturation rate (change in bone age/change in chronological age), and predicted adult height of 10 boys who were treated with spironolactone (5.7 mg/kg x day) and testolactone (40 mg/kg x day) for at least 6 yr. Deslorelin (4 microg/kg x day) treatment was initiated 2.6 +/- 1.3 yr after beginning spironolactone and testolactone treatment. The growth rate normalized within 1 yr of starting treatment and remained normal during the next 5 yr of treatment (P < 0.001). The rate of bone maturation normalized during the second year of treatment and remained normal thereafter (P < 0.001). Predicted height increased from 160.7 +/- 14.7 centimeters at baseline to 173.6 +/- 10.1 centimeters after 6 yr of treatment (P < 0.05 during the fourth through the sixth year of treatment compared to baseline). We conclude that long term treatment with spironolactone, testolactone, and, after central puberty, deslorelin normalizes the growth rate and bone maturation and improves the predicted height in boys with familial male-limited precocious puberty. The ultimate effect of this approach on adult height will require further study.

Use of an ultrasensitive recombinant cell bioassay to determine estrogen levels in girls with precocious puberty treated with a luteinizing hormone-releasing hormone agonist.

Although treatment of girls with precocious puberty should ideally restore estradiol levels to the normal prepubertal range, treatment effectiveness has usually been monitored by gonadotropin levels because estradiol RIAs have lacked sufficient sensitivity to monitor treatment effectiveness. We hypothesized that a recently developed ultrasensitive recombinant cell bioassay for estradiol would have sufficient sensitivity to demonstrate a dose-dependent suppression of estradiol during LH-releasing hormone agonist treatment and to determine whether currently used doses are able to suppress estradiol levels to the normal prepubertal range. Twenty girls with central precocious puberty were assigned randomly to receive deslorelin for 9 months at a dose of 1, 2, or 4 micrograms/ kg.day. A significant dose-response relationship was observed, with mean +/- SD estradiol levels of 16.7 +/- 6.1, 7.9 +/- 1.6, and 6.5 +/- 0.7 pmol/L at the doses of 1, 2, and 4 micrograms/kg.day, respectively (P < 0.01). The highest dose suppressed estradiol levels to just above the 95% confidence limits for normal prepubertal girls (< 0.07-6.3 pmol/L). We conclude that the ultrasensitive bioassay for estradiol has sufficient sensitivity for monitoring the response to LH-releasing hormone agonist treatment of central precocious puberty. Additionally, the observation that the deslorelin dose of 4 micrograms/kg.day did not fully restore estradiol levels to the normal prepubertal range suggests that some girls with precocious puberty may require higher doses to receive the maximal benefit of treatment. We suggest that restoration of estradiol levels to the normal prepubertal range should be the ultimate biochemical measure of efficacy, as estradiol is the key hormone that accelerates growth rate, bone maturation rate, and breast development in girls with precocious puberty.

A preliminary study of flutamide, testolactone, and reduced hydrocortisone dose in the treatment of congenital adrenal hyperplasia.

Treatment outcome in congenital adrenal hyperplasia is often suboptimal due to hyperandrogenism, treatment-induced hypercortisolism, or both. As a new approach, we hypothesized that the effects of androgen could be blocked by an antiandrogen (flutamide) and an inhibitor androgen to estrogen conversion (testolactone), thus allowing the hydrocortisone dose to be reduced. We conducted a short term pilot study in 12 children with congenital adrenal hyperplasia in a randomised cross-over open design to determine whether flutamide, testolactone, reduced hydrocortisone dose, and fludrocortisone are more effective than hydrocortisone and fludrocortisone treatment in normalizing linear growth, weight gain, and bone maturation. Each regimen was administered for 6 months, with a 3-month washout period, consisting of hydrocortisone and fludrocortisone treatment, between regimens. Compared to hydrocortisone and fludrocortisone treatment, the regimen of flutamide, testolactone, reduced hydrocortisone dose (from 12.9 to 7.9 mg/m2 day), and fludrocortisone produced an increase in plasma 17-hydroxyprogesterone levels (P < 0.05) and a decline in urinary cortisol (P < 0.01), linear growth rate (-0.9 +/- 0.5 vs. 1.4 +/- 0.6 SD U; P = 0.003), weight velocity (-0.80 +/- 4.0 vs 0.6 +/- 0.4 SD U; P = 0.01), and bone maturation (0.6 +/- 0.6 vs. 1.4 +/- 0.9 yr bone age/yr chronological age; P = 0.02). Although no important adverse effects were observed, the known potential for flutamide-induced hepatotoxicity made frequent monitoring essential. We conclude that the regimen of flutamide, testolactone, reduced hydrocortisone does, and fludrocortisone improve the short term control of growth and bone maturation in children with congenital adrenal hyperplasia. Long term studies are required to determine whether this approach can improve these children's growth and development.

Premature thelarche and central precocious puberty: the relationship between clinical presentation and the gonadotropin response to luteinizing hormone-releasing hormone.

Premature thelarche is a benign condition that affects young girls. In contrast, central precocious puberty is considered a more serious disorder that causes progressive secondary sexual development, accelerated growth and skeletal maturation, early epiphyseal fusion, and short adult stature. Differentiation between these 2 conditions is important, but may be difficult on clinical grounds, since patients with both disorders may present initially as isolated breast development. To examine the potential usefulness of gonadotropin measurements in distinguishing early central precocious puberty from premature thelarche, we measured basal and LHRH-stimulated plasma gonadotropin levels in 58 girls with idiopathic premature breast development. The girls were divided into six clinically distinct groups, based on the severity of clinical presentation, ranging from isolated breast development (group A) to complete secondary sexual development and accelerated growth and skeletal maturation (group F). The mean basal plasma LH levels and the peak LH response to LHRH stimulation were significantly less in girls with isolated thelarche (group A) than in girls with complete sexual development (group F). The mean basal plasma FSH levels did not differ between these groups, but the peak FSH response to LHRH was greater in girls with isolated thelarche than in girls with complete sexual development. Thus, girls with isolated premature thelarche had a FSH-predominant response to LHRH [mean ratio of peak LH to peak FSH, 0.29 +/- 0.10 (+/- SD)], while girls with complete sexual development had a LH-predominant response (peak LH/FSH, 4.16 +/- 1.80). All girls with isolated thelarche had peak LH/FSH ratios less than 1, and all girls with complete sexual development had a ratio greater than 1. Girls with early or intermediate manifestations of central precocious puberty, who had features of puberty in addition to breast development but lacked all of the features of group F, comprised groups B-E. These girls also had intermediate peak LH/FSH ratios, ranging from 0.29 +/- 0.10 (group B) to 3.35 +/- 2.66 (group E). We conclude that girls with early central precocious puberty frequently have LH and FSH responses to LHRH that are indistinguishable from the FSH-predominant responses of girls with isolated thelarche. These data are consistent with the hypothesis that premature thelarche and central precocious puberty may represent different positions along a continuum of hypothalamic LHRH neuron activation.

Increased final height in precocious puberty after long-term treatment with LHRH agonists: the National Institutes of Health experience.

We report 98 children who have reached final adult height in a long-term trial of LHRH agonist treatment. These children were 5.3 +/- 2.1 yr old at the start of treatment and were treated with either deslorelin (4 microg/kg.d sc) or histrelin (4-10 microg/kg.d) for an average of 6.1 +/- 2.5 yr. Final height averaged 159.8 +/- 7.6 cm in the 80 girls, which was significantly greater than pretreatment predicted height (149.3 +/- 9.6 cm) but still significantly less than midparental height (MPH) (163.7 +/- 5.6). Final height averaged 171.1 +/- 8.7 cm in the 18 boys, which was significantly greater than pretreatment predicted height (156.1 +/- 14.2 cm) but still significantly less than MPH (178.3 +/- 5.2 cm). However, the average adult height of the 54 children who had less than a 2-yr delay in the onset of treatment was not significantly different from their MPH, and 21 children exceeded MPH. Final height SD score correlated positively with duration of treatment (P < 0.01), midparental height (P < 0.001), predicted height at the start of treatment (P < 0.001), and growth velocity during the last year of treatment (P < 0.001) and correlated inversely with delay in the onset of treatment (P < 0.001), age at the start of treatment (P < 0.001), bone age at the start of treatment (P < 0.001), bone age at the end of treatment (P < 0.001), breast stage at the start of treatment (P = 0.02), and bone age minus chronological age at the start of treatment (P = 0.001). We conclude that LHRH agonist treatment improves the final height for children with rapidly progressing precocious puberty treated before the age of 8 yr for girls or 9 yr for boys. Less delay in the onset of treatment, longer duration of treatment, and lower chronological and bone age at the onset of treatment all lead to greater final height. All children with onset of pubertal symptoms before age 8 in girls and age 9 in boys should be evaluated for possible treatment. Treatment is appropriate in children with rapidly progressing puberty, accelerated bone maturation, and compromise of adult height prediction, regardless of bone age or chronological age at time of evaluation. However, once treatment is considered appropriate, it should be initiated quickly, because longer delays lead to shorter final height. In addition, the longer the treatment is continued, the greater is the final height outcome.

Gonadotropin secretory dynamics during puberty in normal girls and boys.

To determine the most useful index of pubertal gonadotropin secretion we measured spontaneous LH and FSH levels every 20 min for 24 h and the LH and FSH responses to LHRH in a total of 37 girls and 30 boys representing each of the 5 stages of puberty. Mean 24-h LH and FSH levels rose significantly with increasing pubertal stage in both girls and boys. LH peak amplitude increased significantly with increasing pubertal stage for both sexes, whereas FSH peak amplitude did not. LH and FSH peaks were present throughout the 24-h period in all children, but the frequency did not change significantly with increasing pubertal stage. Mean gonadotropin levels, peak amplitudes, and peak frequencies tended to be higher at night from pubertal stages 1-4 of puberty. There were no significant sex differences in mean LH, LH peak amplitude, or LH peak frequency. The LHRH-stimulated peak LH to peak FSH ratio was greater in boys than girls during pubertal stages 1-3 and was less useful in distinguishing pubertal from prepubertal boys. For girls, the most accurate index of pubertal gonadotropin secretion was a LHRH-stimulated peak LH to peak FSH ratio greater than 0.66, which detected 96% of the pubertal girls with no false positives. For boys, the most accurate index was a maximum spontaneous nighttime LH level of 12 IU/L or more, which detected 90% of the pubertal boys with no false positives. We conclude that there are important sex differences in the gonadotropin responses to LHRH during puberty, and that criteria for the onset of pubertal gonadotropin secretion should be sex specific.

Boys with precocious puberty due to hypothalamic hamartoma: reproductive axis after discontinuation of gonadotropin-releasing hormone analog therapy.

Hypothalamic hamartoma is an important cause of precocious puberty in boys. Although the GnRH analogs are known to be effective therapy, there are few studies of the recovery of the pituitary-gonadal axis following long-term treatment. To this end, we studied 11 boys with HH after 8.8+/-3.2 yr (range, 4.0-12.6) of treatment with the GnRH agonist D-Trp6,Pro9,NEt-LHRH. The patients' levels of LH and FSH, testosterone, testis volume, and body mass index were compared with those of six normal boys in pubertal stage IV-V. We found that the patients' mean +/- SD peak GnRH-stimulated LH and FSH had returned to the normal range by 1 yr after stopping therapy. Whereas testosterone returned to normal levels by 1 yr, the patients' testis volume remained smaller than normal until 2 yr after therapy. Ultrasonography revealed diffuse, punctate, echogenic foci in the testicular parenchyma of two patients; these were first observed during GnRH agonist therapy and persisted unchanged after discontinuation of treatment. Neither of these two patients reported pain or testicular discomfort, no mass or irregularity was detected by manual examination in either patient at any time, and levels of beta-hCG and alpha1-fetoprotein were normal. By 4 yr after therapy, all patients had pubertal stage V pubic hair; their body mass index was not different from that of the normal boys at any time point. The dimensions of the patients' hamartomas did not change during or after therapy, and no patient reported new neurological symptoms or signs suggestive of an enlarging lesion at any time during or after discontinuation of treatment. Two families did report episodes of emotional lability and truancy as the patients reentered puberty after discontinuation of treatment.

Spontaneous growth hormone secretion increases during puberty in normal girls and boys.

To test the hypothesis that GH secretion increases during puberty, we measured GH levels in samples obtained every 20 min for 24 h from 132 normal children and adolescents. In both girls and boys, GH levels increased during puberty. The increase in mean levels was earlier in girls than boys, was most evident at night, and was due to increased pulse amplitude rather than a change in pulse frequency. The mean nighttime GH level in girls with bone ages (BA) greater than 12 to 14 yr were significantly greater than the mean level in girls with BA less than 8 yr (7.3 +/- 3.0 vs. 3.4 +/- 1.7 micrograms/L; P less than 0.01) and were greatest at breast stage 3 (7.9 +/- 2.5 micrograms/L). GH pulse amplitude increased significantly before pubertal onset in girls and was significantly greater at BA greater than 12 to 14 yr than at BA of 8 yr or less (13.9 +/- 6.0 vs. 7.9 +/- 4.8 micrograms/L; P less than 0.01) and greatest at breast stage 3 (15.0 +/- 6.3 micrograms/L). The pubertal increase in GH secretion was delayed in boys compared to girls, with the lowest mean 24-h GH and mean nighttime GH values in boys with BA greater than 8 to 11 yr. The mean nighttime GH level at BA greater than 11 to 13 yr in boys was significantly greater than that in the boys with BA greater than 8 to 11 yr (5.8 +/- 2.9 vs. 3.5 +/- 2.1 micrograms/L; P less than 0.05) and was greatest at a testicular volume of more than 10 to 15 mL (6.5 +/- 2.0 micrograms/L). The mean nighttime GH pulse amplitude in boys was significantly greater at BA greater than 11 to 13 yr than at BA greater than 8 to 11 yr (13.9 +/- 5.7vs. 7.3 + 2.6 micrograms/L, P less than 0.05) and was greatest at a testicular volume greater than 20 mL (15.8 +/- 12.0 micrograms/L). The mean nighttime GH levels correlated inversely with body mass index in both sexes, although the correlation achieved statistical significance only for the girls, being stronger in breast stage 3 to 5 girls (r = -0.57 P = 0.0007; n = 32) than in stage 1 and 2 girls (r = -0.38; P = 0.03; n = 32). These observations in normal adolescents emphasize the importance of interpreting spontaneous GH levels in short children in relation to normative data appropriate for sex, body mass, and bone age or pubertal stage.