The mechanism of the adolescent growth spurt induced by low dose pulsatile GnRH treatment

We have used GnRH administered in a pulsatile fashion to treat 26 patients (12M:14F) with delayed puberty. Treatment was for a mean of 1.05 years (range, 0.3-1.6). Mean age at the onset of treatment was 16.4 years in the girls (range, 12.7-28.2) and 15.8 years in the boys (range, 13.8-17.8). At different stages of sexual maturation, overnight serum samples for growth hormone (GH) were taken at 15 min intervals between 2000 h and 0600 h. The girls had a peak growth velocity which occurred between breast stages 2 and stage 3 (B2/3). GH secretion (both sum of the GH peaks and area under the GH pulse) increased at B2 and reached a peak at B3. Growth acceleration in the boys started at the attainment of a 9-10 ml testicular volume and reached a peak at 11-15 ml. The boys demonstrated an initial fall in GH secretion with the onset of treatment until the attainment of 9-10 ml testicular volume; peak GH secretion occurred at the attainment of 11-12 ml testicular volume. There was no change in GH pulse frequency during treatment in either sex. These observations and the maintenance of the normal relationship of the growth spurts to the appearance of secondary sexual characteristics are relevant to the mechanisms and timing of the adolescent growth spurts in normal girls and boys.

Effects of testosterone therapy for pubertal delay

We reviewed the effects of a brief course of testosterone enanthate (four intramuscular injections of 200 mg at three-week intervals) on pubertal advancement and final adult height in 50 male patients with delayed puberty. Although those treated with testosterone were slightly older than a group of 38 untreated subjects, the two groups had similar baseline mean bone age delays, height z scores, Tanner stages, predicted adult heights, growth rates, and midparental heights. Four months after baseline, the treated group had a significantly greater mean increase in the height z score and sexual maturation index. At 12 months, the mean increase in the sexual maturation index remained greater in the treated group. Among treated and untreated subjects older than 17 years, there was no significant difference in the absolute height z score. Over 95% of treated subjects were satisfied with the effects of therapy.

The effect of long-term opiate antagonist administration to pubertal boys

To test further the hypothesis that opiatergic pathways controlling gonadotropin production may be functional during early to mid adolescence, nine pubertal boys with bone ages ranging from 10 to 15 were given the long-acting opiate antagonist, naltrexone, for up to 4 weeks. Urinary gonadotropin measurements were assessed before, during, and after drug administration. In three early to mid-pubertal boys who received naltrexone for 3 to 4 weeks, LRH testing was also performed. No evidence of a stimulatory FSH or LH response to naltrexone was found in any of the patients evaluated. The data do not support the operation of an opiate-mediated mechanism in the control of pubertal onset in man.

Isolated gonadotropin deficiency in boys: clinical characteristics and growth

Analysis of the clinical findings and growth in 20 boys with isolated gonadotropin deficiency revealed a heterogeneous group of physical abnormalities. Ten of these patients were hyposmic or anosmic (Kallmann syndrome). Abnormalities found in our patients included undescended testes, gynecomastia, and ocular or skeletal anomalies. Regardless of the presence of hyposmia, patients without testicular enlargement (less than 2 cm3), had serum luteinizing hormone (LH) responses to luteinizing hormone-releasing factor (LRF) that were the same as in prepubertal boys. By contrast, five boys with testicular enlargement (greater than 2 cm3), some of whom had hyposmia, had a greater serum LH response to LRF than did prepubertal boys. Adrenarche was moderately delayed; although all boys initially had normal serum levels of dehydroepiandrosterone-sulfate, four boys eventually developed elevated serum levels. Bone ages were delayed compared with chronologic age in boys who had the condition after 15 years of age. The rate of linear growth was normal, and final adult heights were normal with testosterone therapy, although linear growth continued longer in these boys than in boys with normal pubertal progression. Although none of the patients was obese at the time of diagnosis, three patients developed obesity after initiation of testosterone therapy.

Induction of puberty by pulsatile gonadotropin releasing hormone

15 girls and 17 boys with delayed or arrested puberty were treated with gonadotropin releasing hormone (GnRH) for a mean of 1.04 years. GnRH was administered subcutaneously in a pulsatile fashion at 90 min intervals, and the dose was increased as required to maintain progression of puberty, initially only at night and subsequently over 24 h. Initial GnRH dose was 1-2 micrograms per pulse in the girls and 2-4 micrograms per pulse in the boys. The effect of treatment was monitored by serial overnight gonadotropin profiles in all patients and with pelvic ultrasound in the girls. The clinical features, growth acceleration, endocrinology, and ovarian ultrasound morphology of puberty were those seen in normal children. Measurement of spontaneous gonadotropin pulsatility after treatment had been discontinued allowed the distinction between 20 patients with hypogonadotropic hypogonadism and 12 who had constitutional delay of growth and puberty. 2 girls and 6 boys did not respond to the treatment regimen. These findings indicate that normal puberty is GnRH dependent.

Treatment of short stature and delayed adolescence

The treatment of growth failure in children with documented GH deficiency remains the only noncontroversial indication for GH therapy. There are increasing data suggesting that GH may be useful in treating some children with Turner's syndrome and with NVSS. Further studies, however, are necessary to evaluate the long-term efficacy and safety of GH therapy in these children. The treatment of non-GH deficient children whose heights are within two standard deviations of the mean height for age is clearly inappropriate and should be avoided, despite parental protests.

Induction of first cycles in primary hypothalamic amenorrhea with pulsatile luteinizing hormone-releasing hormone: a mirror of female pubertal development

During pubertal development in girls, the attainment of regular ovulatory menstrual cycles usually is preceded by cycles that are either anovulatory or show a defective luteal phase. It is not known whether these defective cycles are caused by inadequate luteinizing hormone-releasing hormone (LH-RH) secretion or by an inadequate response of the pituitary-ovarian axis to LH-RH stimulation. To shed new light on this matter, the authors analyzed endocrine data from 12 menstrual cycles induced by pulsatile LH-RH therapy in five women with primary amenorrhea of hypothalamic origin. Anovulatory cycles occurred with and without an increase in estrogen excretion and with and without a luteinizing hormone surge. In addition, ovulatory cycles with and without deficient corpus luteum function were observed. Most of these types of anovulatory and ovulatory menstrual cycles also have been described during normal puberty. Therefore, these observations suggest that, during normal pubertal development, maturation of the pituitary gonadotropes and of the ovary occurs, as well as the increased secretion of LH-RH from the hypothalamus, which the overall process depends upon.

Short-term testosterone treatment at bone age of 12 to 13 years does not reduce adult height in boys with constitutional delay of growth and adolescence

Growth data and adult height from 22 untreated patients with constitutional delay of growth and adolescence (group 1) were compared retrospectively with those of 19 patients, who had received long-acting testosterone esters (100 to 250 mg per month, mean total dosage 1029 mg/m2) during 2 months to 3.25 years (mean duration 8.5 months, group 2). Age (group 1 15.4 +/- 1.2, group 2 16.2 +/- 1.4 years), bone age (group 1 12.6 +/- 1.3, group 2 13.1 +/- 1.2 years) at first examination (group 1) or start of treatment (group 2), and adult height (172.8 +/- 7.5 cm group 1, 176.8 +/- 8.0 cm group 2) were not significantly different. In group 2, there was no negative correlation between the total testosterone dose and adult height, and the latter corresponded to predicted height in the same way as in the untreated patients. It is concluded that short-term treatment with long-acting testosterone esters (100 to 250 mg per month during 6 months, starting at a bone age of about 12.5 years), which has positive psychosocial effects, does not have negative somatic effects and does not reduce adult height in these patients.

Urticaria associated with antigonadotropin-releasing hormone antibody in a female Kallman's syndrome patient being treated with long-term pulsatile gonadotropin-releasing hormone

The administration of pulsatile gonadotropin-releasing hormone (GnRH) has received increasing attention as a method of inducing ovulation or initiating puberty. Few side effects have been reported, although urticarial allergic reactions have been reported in the male. An 18-year-old female with hypogonadotropic hypogonadism and anosmia due to lack of endogenous GnRH was treated for 230 days using subcutaneous GnRH in an attempt to induce physiologic puberty. Just before anticipated menarche, therapy was discontinued because of the appearance of an urticarial reaction at the injection site as well as at previous injection sites. The presence of immunoglobulin G (IgG) antibodies against GnRH were subsequently identified in the patient's serum. These results further confirm the potential for antibody production to this small natural peptide in the female not previously exposed to GnRH. Some practical considerations for this form of therapy are highlighted.

Decrease in plasma high-density lipoprotein cholesterol levels at puberty in boys with delayed adolescence. Correlation with plasma testosterone levels

A three-phase study tested the hypothesis that the decrease in the high-density lipoprotein cholesterol (HDL-C) level observed in boys at puberty is related to an increase in the plasma testosterone concentration. In phase I, 57 boys aged 10 to 17 years were categorized into four pubertal stages based on clinical parameters and plasma testosterone levels. These four groups showed increasing plasma testosterone values and decreasing HDL-C levels. In phase II, 14 boys with delayed adolescence were treated with testosterone enanthate (100, 200, and 200 mg/mo, respectively, for three months). Plasma testosterone levels during therapy were in the adult male range. Levels of HDL-C decreased by a mean of 7.4 mg/dL (0.20 mmol/L) and 13.7 mg/dL (0.35 mmol/L), respectively, after the first two doses. In phase III, 13 boys with delayed adolescence demonstrated increasing plasma testosterone levels and decreasing HDL-C levels (-12.0 mg/dL [-0.30 mmol/L]) during spontaneous puberty. Levels of HDL-C and apolipoprotein A-1 were correlated during induced and spontaneous puberty. Testosterone should be considered a significant determinant (not necessarily directly causal) of plasma HDL-C levels during pubertal development.

[Pulsatile long-term gonadotropin-releasing hormone (GnRH) therapy in the male: natural induction of puberty in a 20-year-old boy]

Successful induction of puberty by means of a pulsatile long-term therapy with GnRH--the variant closest to nature--can be performed on an outpatient basis without changing habits and lifestyle, as was demonstrated clinically and biochemically in a 20-year-old previously untreated boy with hypothalamic hypogonadism of unknown etiology. Unusual in this patient's course was the slow--and modest--increase in plasma FSH levels. Evidence that puberty did not occur spontaneously but was in fact due to treatment was gained from gonadotropin profiling by night and day before and after therapy withdrawal.

[Puberty induction using pulsatile LHRH administration]

Puberty is a maturational process of the hypothalamo-pituitary-gonadal axis resulting in growth and development of the genital organs and concomitantly physical changes. All these changes are the result of an increasing activity of the pituitary and consequently of the gonads caused by increased stimulation by the luteinizing hormone-releasing hormone (LHRH). Delayed puberty is a common problem in contrast to true hypogonadotropic hypogonadism. Since a few years pulsatile LHRH administration is applied to induce pubertal development in hypogonadotropic boys. Except for virilisation, development of the testes including spermatogenesis can be achieved. In contrast to boys, substitution with sex steroids brings about a satisfactory physiologic development of the sex characteristics in girls. The physiology and disorders of pubertal development as well as this new LHRH treatment to induce puberty will be discussed in this paper.

Markedly delayed puberty or Kallmann's syndrome variant

A diagnosis of Kallmann's syndrome was made in a 25-year-old man. After 21 months of treatment with parenteral T, spontaneous puberty occurred at the age of 27.

Low-dose testosterone effect on somatic growth

Low-dose testosterone has been found to preserve the growth potential of hypogonadal children requiring anabolic or androgenic therapy. Five girls with Turner syndrome were treated when their chronologic ages were 13 to 14 years and their bone ages were 10.6 to 12.75 years; six hypogonadal boys were treated when their chronologic ages were 11 to 15 years and their bone ages were 10.9 to 14.2 years. Depot testosterone was given as an anabolic agent in an average dose of 28 mg/m2/mo for 6 months to the patients with Turner syndrome and was given to initiate puberty in an average dose of 44 mg/m2/mo for 6 months to the hypogonadal boys. Growth rate doubled on these doses of testosterone, and bone age did not advance disproportionately. Consequently, height potential was preserved. Pubic hair advanced one Tanner stage during the 6-month treatment. Clitoral hypertrophy was observed in only one of the five girls with Turner syndrome and regressed when testosterone therapy was discontinued. Four hypogonadal boys were continued on low-dose testosterone until their bone ages passed 14 years of age and their growth rate waned. Then, the testosterone dosage was increased in increments to 100 to 200 mg/m2/mo. This group reached a height of 100.3 +/- 0.8% of the height initially predicted. In addition, all attained an adult height at least 15 percentiles greater than that before therapy. These studies indicate that testosterone in very low doses resembles "anabolic steroids" in that growth is stimulated without an inordinate androgenic effect. Furthermore, these studies show that institution of low-dose therapy in the early teenage years stimulates pubertal growth normally without loss of height potential.

[Induction of puberty by pulsatile luteinizing hormone releasing hormone (LH-RH)--therapy in a boy with Kallmann syndrome]

To induce the lacking development of puberty, a male patient with hypothalamic hypogonadism and anosmia (Kallmann's syndrome) was treated with pulsatile application of gonadotropin-releasing hormone (GnRH) to imitate the endogenous secretion of GnRH. The low-dose pulsatile GnRH treatment which was reported to be successful by various authors proved to be ineffective when administered to our patient subcutaneously as well as intravenously. Serum testosterone levels comparable to the lower normal values in adults and continuous progress of pubertal development were only achieved after increasing the dosage from 2 to 8 micrograms per pulse by subcutaneous application. The course of therapy is reported in detail.

Pulsatile gonadotropin-releasing hormone treatment in idiopathic delayed puberty

Idiopathic delayed male puberty is defined as a delay of puberty beyond the age of 16, with prepubertal testosterone levels, normal gonadotropin responses to GnRH (excluding pituitary failure), and normal androgen responses to a single hCG injection (excluding testicular Leydig cell dysfunction), in absence of serious disease. Ten boys with this condition were evaluated as to their spontaneous LH, FSH, and PRL secretory patterns during a 24-h sampling period (20-min intervals). After this all patients were treated with pulsatile infusions of GnRH (25 ng/kg . pulse every 90 min for 10 days. Two groups could be distinguished by means of their pretreatment LH secretory pattern. Five patients had nighttime pulsatile elevation of LH levels, as usually occurs in early puberty. The other five patients did not have such a pattern (prepubertal type). The GnRH treatment resulted in increased LH and testosterone levels in both groups. All patients with pretreatment nighttime pulsatile LH secretion had steady pubertal development during the post-GnRH treatment observation period, whereas the other patients did not. In conclusion, among a number of tests, including chronic pulsatile GnRH treatment for 10 days, only the nocturnal LH secretory pattern differentiated delayed puberty from permanent hypothalamic hypogonadism in boys.

Disturbances of puberty

The initiation and progress of puberty requires progressive pulsatile stimulation of the pituitary by GnRH and of the gonads by LH and FSH. Gonadal maturation continues throughout childhood and is not confined to puberty. We have discussed the events of normal puberty and emphasized the consonance of the acquisition of different components of sexual maturation, including growth acceleration. Departure from this consonance is a sign of abnormality. The method by which constitutional delay of growth and puberty can be distinguished from gonadotrophin deficiency has been discussed as well as the treatment options for both conditions. We have emphasized the significance of pulsatile gonadotrophin secretion and how the development of a multicystic ovarian morphology on ultrasound can be used as a non-invasive assessment of gonadotrophin pulsatility in girls. Pulsatile GnRH therapy mimics normal puberty. The converse of suppressing the clinical signs of central precocious puberty can be achieved by abolishing gonadotrophin pulsatility with GnRH analogue therapy. We now recognize qualitative pulse abnormalities of gonadotrophin secretion which occur in isolated premature thelarche and in some cases of delayed puberty. Although clinical assessment remains the key to the diagnosis of disorders of puberty, studies of gonadotrophin pulsatility have aided our understanding and treatment of these conditions.

Events surrounding the initiation of puberty with long term subcutaneous pulsatile gonadotropin-releasing hormone in a female patient with Kallman's syndrome

An 18-yr-old woman with primary amenorrhea, anosmia, and total lack of secondary sexual development was treated for 230 days using sc pulsatile GnRH. GnRH testing with 100 micrograms, sc, initially revealed a peak FSH to LH ratio greater than 1. After 28 days of treatment, this ratio had reversed. A dosage of 20 micrograms/2 h for 200 days resulted in a LH to FSH ratio greater than 2. Widening the interval to 20 micrograms/3 h significantly lowered LH, but not FSH, levels. Increasing the frequency to 20 micrograms/90 min again increased the LH to FSH ratio. Twenty-four-hour testing revealed a sleep-entrained PRL rise both during and after GnRH therapy, but no sleep-entrained rise in LH. Ultrasound monitoring revealed cyclic changes in ovarian diameter at 30- to 60-day intervals that coincided with cyclic increases in LH and estradiol. The uterine fundus doubled in length between days 50 and 110 of treatment. The patient progressed from Tanner pubic hair and breast stage I to stage II during treatment, which was terminated due to an allergic reaction to GnRH. This study provides the first report of hormonal and ultrasound events surrounding puberty induction with GnRH in the female. We conclude widening the interval of GnRH administration can reduce LH levels while maintaining FSH levels, cyclic changes in ovarian diameter, LH, and estradiol occur before menarche, and although pulsatile GnRH provides a fascinating model for the study of puberty in the female, the chronicity of therapy needed and its potential for allergic reaction make this method of inducing puberty suboptimal.