Hormone-releasing Hormone Test Research Articles

Idiopathic central precocious puberty in a Klinefelter patient: highlights on gonadotropin levels and pathophysiology

BackgroundIdiopathic central precocious puberty (ICPP) is supposed to be non-existent in a context of testicular destruction that is typically present in Klinefelter syndrome (KS). Herein, we describe a rare case of ICPP in a Klinefelter patient (47,XXY) with 2 maternal X chromosomes. Moreover, we highlight the differences in gonadotropin levels in comparison to males with ICPP and a normal karyotype.Case presentationAn 8 years old boy with a history of cryptorchidism was evaluated for precocious puberty (Tanner staging: P2/G3). Both testes measured 25x35mm. His hormonal profile confirmed a central origin of precocious puberty with high serum testosterone (4.3 ng/ml), luteinizing hormone [LH (3.5 UI/l)] and follicle stimulating hormone [FSH (7.7 UI/l)] levels. Luteinizing hormone-releasing hormone (LHRH) test amplified LH and FSH secretion to 24 and 14 UI/l respectively. Brain magnetic resonance imaging (MRI) was normal. No MKRN3 mutation was detected. He was treated for ICPP for two years. During puberty, he suffered from hypergonadotropic hypogonadism leading to the diagnosis of KS (47,XXY karyotype). Chromosomal analysis by fluorescent multiplex polymerase chain reaction (PCR) using X chromosome microsatellite markers identified 2 maternal X chromosomes.Analysing 8 cases of KS developing ICPP (our reported case and 7 other published cases) revealed that these KS patients with ICPP have higher LH and FSH levels during ICPP episode than in ICPP patients with a normal karyotype (ICPP with KS vs ICPP with a normal karyotype: LH levels 9.4 ± 12 vs 1.1 ± 0.6 UI/l; FSH levels 23.1 ± 38.5 vs 2.7 ± 1.5 UI/l). Furthermore, their response to gonadotropin-releasing hormone (GnRH) stimulation is characterized by excessive LH and FSH secretion (LH levels post-GnRH: 58 ± 48 vs 15.5 ± 0.8 UI/l; FSH levels post-GnRH: 49.1 ± 62.1 vs 5.7 ± 3.9 UI/l).ConclusionsICPP in boys is extremely rare. The pathophysiology of ICPP in KS is unknown. However, maternal X supplementary chromosome and early testicular destruction may play a significant role in the initiation of ICPP, in part explaining the relative “overrepresentation of ICPP in KS. Thus, karyotype analysis could be considered for boys suffering from ICPP, especially if testicular size is smaller or gonadotropins are significantly elevated.

Changes in Body Mass Index in Girls with Idiopathic Central Precocious Puberty under Gonadotropin-Releasing Hormone Analogue Therapy: The Spanish Registry

Background: The influence of gonadotropin-releasing hormone analogue (GnRHa) treatment on body mass index (BMI) evolution in girls with idiopathic central precocious puberty (CPP) is unclear. Hence, we aimed to evaluate the effect of GnRHa treatment on BMI-standard deviation score (SDS) from diagnosis of idiopathic CPP until adult height. Methods: An observational study of girls diagnosed with CPP in Spain was carried out between January 2008 and December 2014. A computer program was designed to process clinical and biological data from patients treated in 55 departments of pediatric endocrinology throughout the country. The inclusion criteria were (1) girls diagnosed with CPP before 8 years of age; (2) born after 1992; (3) with a difference between bone and chronological age of at least 1 year, and (4) with a luteinizing hormone peak >7 U/l during luteinizing hormone-releasing hormone testing. The influence of GnRHa treatment on BMI-SDS evolution was analyzed. Results: Data from 333 girls (22.2% adopted) were evaluated. We report follow-up data at 6, 12, 24, 36, 48 and 60 months and adult height from 269, 232, 198, 153, 105, 56 and 49 girls, respectively. During treatment, there was an increase in BMI-SDS of 0.43 ± 1.17 (95% CI: 0.20-0.64). At adult height (n = 49), BMI-SDS was 1.51 ± 1.38, which was 0.60 ± 1.09 higher than at diagnosis (95% CI: 0.43-0.75). Conclusions: During treatment with GnRHa, girls experience a significant increase in BMI-SDS that persists after therapy is stopped and adult height has been reached.

Severe growth hormone deficiency and empty sella in obesity: a cross-sectional study.

Obesity is associated with blunted growth hormone (GH) secretion. In some individuals, hypothalamic-pituitary (HP) structural lesions may contribute to GH deficiency (GHD). We explored pituitary morphology in obese patients with suspected GHD and its association with cardiovascular risk factors, body composition, and cardiac morphology. One hundred and eighty-four adults obese patients with symptoms and signs of GHD (147 females and 37 males; mean age 46.31 ± 12.11 years), out of 906 consecutive white obese outpatients, were evaluated. The main measures were anthropometric data, blood pressure, lipid profile, glycemic parameters, pituitary hormones, and insulin-like growth factor-1 values, echocardiography, magnetic resonance imaging (MRI) of the HP region, body composition, and growth hormone-releasing hormone plus arginine test. Seventy patients had GHD (GH peak values <4.2 μg/mL). GHD patients showed significantly higher body mass index and fat mass, lower lumbar bone mineral density, increased left ventricular mass index, and epicardial fat thickness. The MRI of the HP region showed empty sella (ES) in 69 and normal pituitary in one of the 70 GHD patients; the 114 patients with normal GH response had ES (n = 62, 54 %), normal pituitary (n = 37, 32 %), microadenomas (n = 10, 8 %), and other pituitary abnormalities (n = 5, 4 %). ES was a significant independent predictor of GH secretory capacity as determined by multiple regression analysis. The close relationship between ES and GH secretory capacity points out to the possibility of the organic nature of GHD in a portion of obese individuals and opens a new scenario with regard to the potential of GH treatment on metabolic consequences of obesity.

Mutational analysis of KISS1 and KISS1R in idiopathic central precocious puberty

The genetic background of idiopathic central precocious puberty (ICPP) is not well understood. The genetic activation of pubertal onset is thought to arise from the effect of multiple genes. Familial ICPP has been reported suggesting the existence of monogenic causes of ICPP. Kisspeptin and its receptor are found to be involved in gonadotropin-releasing hormone (GnRH) secretion and puberty onset. Mutations in their genes, KISS1 and KISSR, have been suggested to be causative for ICPP. ICPP was defined by pubertal onset before 8 years of age in girls, and a pubertal luteinizing hormone (LH) response to GnRH testing. Twenty-eight girls with ICPP were included in the study [age at diagnosis was 5.72±2.59, with a mean bone age advancement of 1.4 years (-0.1 to 2.8). Height at onset of therapy in SD score was 0.90±1.48 for age]. Luteinizing hormone-releasing hormone test was performed in all subjects, and all of them had a pubertal response (LH 20.35±32.37 mIU/mL; FSH 23.32±15.72 mIU/mL). The coding regions of KISS1 and KISS1R were sequenced. No rare variants were detected in KISS1 or KISS1R in the 28 subjects with ICPP. We confirmed that mutations in KISS1 and KISS1R are not a common cause for ICPP.

Testing for growth hormone deficiency in adults

This article summarizes recent advances in testing for growth hormone deficiency (GHD) in adults, focusing on critical appraisal of existing growth hormone (GH) provocative tests as well as newer tests in development. The diagnosis of GHD can be challenging and often requires the use of GH provocative testing. The most widely validated of these is insulin-induced hypoglycemia (ITT), which requires close supervision and has significant contraindications and side-effects. The arginine-growth hormone-releasing hormone (GHRH) test had become widely used as a safe and accurate alternative to the ITT, but GHRH is currently unavailable for clinical use in the USA. On the basis of review of recent literature we recommend that in the absence of GHRH, glucagon stimulation testing should be the preferred alternative to ITT. Several synthetic GH secretagogues that mimic the gastric peptide ghrelin are currently in development and may become available for use in the diagnosis of GHD in the near future. Other GH provocative tests suitable for use in children lack adequate specificity for the diagnosis of GHD in adults. Due to the current unavailability of the arginine-GHRH test in the USA, when ITT is contraindicated or impractical we recommend the glucagon stimulation testing as the GH provocative test of choice. There remains a need for a simple, safe and accurate test for the diagnosis of GHD.

First case of a Japanese girl with Myhre syndrome due to a heterozygous SMAD4 mutation

This article reports the first case of a Japanese girl with molecularly confirmed Myhre syndrome (MS). The patient was 9 years old at her first visit, and she had been diagnosed with unknown skeletal dysplasia. Her phenotype fulfilled the clinical and radiological criteria for MS, such as typical facies with prognathism, hearing impairment, short stature, square body shape, and limited joint mobility. The thick calvarium and thick skin were clues to the clinical diagnosis of MS. A heterozygous mutation in the mothers-against-DPP homolog 4 (SMAD4) gene has been reported to cause MS. We sequenced SMAD4 using standard PCR-based technique and identified a recurrent mutation (p.Ile500 Thr). She attained menarche before 11 years of age; however, she developed oligomenorrhea after a few years of 40-day cycles, necessitating hormone replacement therapy. The luteinizing hormone-releasing hormone (LHRH) tests suggested abnormalities related to hypothalamo-hypophyseal malfunction. Previous reports on MS described early menarche in girls and early or delayed puberty and cryptorchidism in boys. Therefore, we recommend performing an endocrinological evaluation of the hypothalamo-hypophyseal-gonadal axis in patients with MS to clarify whether hormonal abnormalities are associated with the syndrome.

Successful pregnancy after the treatment of primary amenorrhea in a patient with non‐classical congenital adrenal hyperplasia

We describe a case of non-classical congenital adrenal hyperplasia (NCCAH) due to 21-hydroxylase deficiency in a 30-year-old Japanese woman who achieved pregnancy after treatment of primary amenorrhea. Hirsutism and clitoromegaly were present. Ultrasound examination showed polycystic appearance of the ovary. Luteinizing hormone-releasing hormone (LH-RH) test resulted in exaggerated LH response, showing a polycystic ovary syndrome (PCOS) pattern. The diagnosis was based on the elevated intial levels of 17-hydroxyprogesterone (55 ng/mL) and dihydroepiandosterone (7780 ng/mL). The first withdrawal bleeding occurred within 6 weeks after treatment with hydrocortisone (20 mg/day) combined with conjugated estrogens (1.25 mg/day) and medroxyprogesterone acetate (10 mg/day), which were continued for five courses. The bleeding remained cyclic every 28 days with maintenance doses of hydrocortisone. Subsequently, ovulation was induced using clomiphene citrate (100 mg/day). Pregnancy was achieved at the second attempt of ovulation induction and was within 10 months after initial presentation. Continuing hydrocortisone, the patient delivered a healthy baby at term.

A girl with Hajdu-Cheney syndrome and premature ovarian failure

Hajdu-Cheney syndrome is an autosomal dominant disorder characterized by acroosteolysis of the distal phalanges associated with digit abnormalities, distinctive craniofacial changes, dental anomalies, and a proportionate short stature. The pubertal development of children with Hajdu-Cheney syndrome is usually normal in the literature, although we here first describe a girl who was found to have Hajdu-Cheney syndrome accompanied with premature ovarian failure. She showed a follicle-stimulating hormone-dominant response on luteinizing hormone-releasing hormone test and did not show any sex differentiation abnormality or adrenal steroid hormone deficiency. On the basis of the findings in our patient, premature ovarian failure may be a complication of Hajdu-Cheney syndrome and thus an early endocrinological evaluation of patients is important.

Case of isolated adrenocorticotropic hormone deficiency mimicking major depressive disorder

ISOLATED ADRENOCORTICOTROPIC HORMONE (ACTH) deficiency is a rare pituitary disorder characterized by decreased secretion of ACTH, but not of the other hormones of the anterior pituitary and causes secondary adrenal insufficiency.1 Since isolated ACTH deficiency gradually and latently develops and shows non-specific symptoms, it is easily misdiagnosed. We report a case of middle-aged-onset isolated ACTH deficiency that showed a severe major depressive episode. A 62-year-old man was admitted to our hospital due to suicidal behavior. He did not have any previous history of neuropsychiatric or endocrine disorders. From 6 months before the admission, he complained of mild general fatigue, depressed mood, loss of pleasure, psychomotor retardation, insomnia, decrease in appetite, and weight loss. He was diagnosed as having major depressive disorder. A dose of 100 mg/day of sertraline did not relieve him of his depressive symptoms at all. At the time of admission, he was fully conscious and showed a severe major depressive episode with suicidal ideas. He did not show any symptoms suggestive of atypical depression or chronic fatigue syndrome, such as hypersomnia, lead paralysis, mood reactivity, rejection sensitivity, muscle pain, lymph node swelling, and fever. Magnetic resonance imaging of his brain did not show any structural abnormality, including an empty sella. Blood test revealed anemia (red blood cell count, 3.24 × 106/µL; hemoglobin, 10.0 mg/dL) and hyponatremia (117 mEq/L). Thyroid function studies were consistent with hypothyroidism: thyroid-stimulating hormone (TSH), 49.8 µIU/mL (normal range, 0.6–5.1); fT3, 2.45 pg/mL (2.47–4.34); and fT4, 0.71 ng/dL (0.97–1.79). Rheumatoid factor and antinuclear, antithyroglobulin, anti-thyroid peroxidase, TSH-receptor, and antipituitary antibodies were negative. Both serum ACTH (<2.0 pg/mL; normal range, 7.2–63.3) and cortisol (0.2 µg; 3.7–19.4) were extremely low, whereas aldosterone (61.6 pg/mL; 38.9–307.0) was within normal range. Neither ACTH nor cortisol responded to corticotrophin-releasing hormone stimulation test, showing that he suffered from secondary adrenocortical insufficiency. Thyrotropin-releasing hormone test, gonadotrophin-releasing hormone test, and growth hormone-releasing hormone test showed normal responses, revealing that his secondary adrenocortical insufficiency was caused by isolated ACTH insufficiency. We discontinued sertraline and started to administer him 5 mg/day of hydrocortisone. Three days later, his symptoms mimicking major depressive episode were dramatically resolved. As in our case, isolated ACTH deficiency may be comorbid with primary hypothyroidism although the mechanism of the coexistence is unknown.2 However, the comorbid hypothyroidism did not seem to induce his depressive state as hypothyroidism was recovered 4 months after rapid relief of his psychiatric state. Relationships between glucocorticoid function and symptoms mimicking major depressive episodes are complex but might reflect insufficient glucocorticoid signaling. Some major depressive episodes might be associated with the insufficient glucocorticoid signaling by decrease of glucocorticoid production or decrease of sensitivity of glucocorticoid receptors.3 Our case suggests that isolated ACTH deficiency should be added into a differential diagnostic list of major depressive disorder. The patient gave the authors informed consent to publish this letter.

Difference in growth hormone response to growth hormone-releasing hormone (GHRH) testing following GHRH subacute treatment in normal aging and growth hormone-deficient adults: Possible perspectives for therapeutic use of GHRH or its analogs in elderly subjects?

The somatotroph axis function shows a decline in the elderly (somatopause). In particular growth hormone (GH) response to GH-releasing hormone (GHRH) is reduced in aged man but less than that observed in GH-deficient adults (GHDAs). Plasma GH response to GHRH (1 µg/kg BW) was significantly lower in four GHDAs than in seven healthy aged men 30, 60, and 90 min after acute GHRH administration. To verify whether a priming regimen might be able to increase the reduced GH response to GHRH, both healthy aged men and GHDA patients underwent repetitive administration of GHRH (100 µg GHRH intravenously as a single morning dose, every 2 days for 12 days). After the GHRH-priming regimen, plasma GH values 30, 60, and 90 min after the acute GHRH test were significantly higher than values at the corresponding time points before priming regimen in healthy aged men but not in GHDA patients. These findings confirmed that somatotroph cells become less sensitive to GHRH with normal aging and demonstrate that repetitive administration of GHRH restores the attenuated response only in healthy aged men but not in GHDA patients. This could support the possible use of GHRH or its analogs instead of recombinant human GH in elderly patients with the advantage of preserving the endogenous pulses of GH with the secretion of the different isoforms of GH. However, concerns arise about the possible role of these molecules in tumorigenesis and tumor growth promotion.

Comparative Validation of the Growth Hormone-Releasing Hormone and Arginine Test for the Diagnosis of Adult Growth Hormone Deficiency Using a Growth Hormone Assay Conforming to Recent International Recommendations

The GHRH plus arginine (GHRH+Arg) test is a promising alternative to the insulin tolerance test (ITT) for diagnosis of adult GH deficiency (AGHD). The objectives of the study were to validate the GHRH+Arg test for diagnosis of AGHD, using the ITT as comparator and a GH assay calibrated according to recent international recommendations, and to study the repeatability and tolerance of both tests. This was a multicenter, randomized, open-label, phase III study. The study was conducted at 10 French university hospitals. Sixty-nine subjects (38 and 15 with high and low probability of GH deficiency, respectively, and 16 healthy controls) were randomized: 35 to the GHRH+Arg-GHRH+Arg-ITT test sequence and 34 to the ITT-ITT-GHRH+Arg test sequence. Each subject underwent three tests of GH secretion separated by 24 h or more. The primary variable used for response assessments was serum peak GH response. Test results were compared with the final AGHD diagnosis. Peak GH responses in the two tests were strongly correlated. A cutoff value of 7.89 microg/liter for GHRH+Arg corresponding to 3 microg/liter for ITT was calculated. The cutoff value leading to 95% specificity with the GHRH+Arg test was measured at about 3.67 microg/liter (sensitivity 79.0%). Intermethod agreement and repeatability were high. Both tests were well tolerated. A preference for the GHRH+Arg test was expressed by 74% of subjects. The GHRH+Arg test demonstrated good accuracy and repeatability, was at least as sensitive as the ITT, and was associated with better subject acceptability. The GHRH+Arg test represents a good alternative to the ITT for the diagnosis of AGHD.

Serum ghrelin levels in growth hormone-sufficient and growth hormone-deficient patients during growth hormone-releasing hormone plus arginine test

Ghrelin is an orexigenic hormone produced in the stomach and in other organs, exerting a wide range of metabolic functions, including stimulation of GH secretion. Ghrelin secretion is decreased by iv or oral glucose load as well as during euglycemic-hyperinsulinemic clamp and hypoglycemia. We evaluated the circulating ghrelin levels in GH-deficient (GHD) and in GH-sufficient (GHS) patients during GHRH plus arginine test. The study group comprised 35 patients, including 20 with pituitary tumors, 12 with empty sella, 2 with short stature, and 1 with post-traumatic isolated GH deficiency. According to the results of GHRH plus arginine test, 14 patients were defined as GHD and 21 as GHS. Patients with central hypothyroidism, hypocorticism, and hypogonadism had been on replacement therapy for at least 3 months at the moment of the study. Blood samples were collected every 20 min up to 60 min after GHRH and arginine administration. By definition, GH response to GHRH plus arginine was higher in GHS than GHD group (p<0.0001). Basal serum ghrelin levels were not different in the two groups and did not correlate with body mass index, GH, IGFI and insulin concentrations. After GHRH plus arginine, serum ghrelin decreased significantly in both groups, with percent decreases ranging 13.3-66.6% in GHD patients (p=0.001) and 7.2-42.2% in GHS patients (p=0.004), with no significant difference in the two groups (p=0.12). Our results show that ghrelin secretion is not modulated by acute GH increase observed in GHS subjects during GHRH plus arginine infusion. The similar decrease of serum ghrelin after GHRH plus arginine stimulation in both GHS and GHD subjects demonstrated that there is no negative feedback of GH on ghrelin secretion.

Clinical evaluation of the luteinizing hormone-releasing hormone (LH-RH) test in cases with anatomically verified disorders of the hypothalamo-pituitary region.

The effect of slow intravenous infusion of luteinizing hormone-releasing hormone (LH-RH) on serum LH was studied in 58 patients with anatomically verified hypothalamo-pituitary disorders as well as in control groups. Normal responses to the LH-RH test were found in 15 out of 15 cases with intrasellar pituitary tumours and in five out of six cases after transsphenoidal surgery for an intrasellar pituitary tumour. Twenty-one out of 25 patients where a pituitary tumour with both supra- and intrasellar extension had been removed had pathological responses to the test. All eight patients with hypothalamic disorders, mainly tumours not directly influencing the pituitary, gave normal responses to the LH-RH tests. Out of four patients with hypothalamopituitary malformations a pathological response to the LH-RH infusion was found in three cases and a normal response in one case. The increase of serum LH after LH-RH infusion was pronounced and rather constant in males and post-menopausal women. It was more difficult to evaluate a “normal” test response in women of fertile ages because of the great variations during the different menstrual phases. It is concluded that the LH-RH test may be of importance in the investigation of patients with suspected tumours of the pituitary as well as for differential diagnosis between hypothalamic and pituitary disorders of gonadotropin secretion.

Combined Growth Hormone-Releasing Hormone and Growth Hormone-Releasing Peptide-6 Test for the Evaluation of Growth Hormone Secretion in Children with Growth Hormone Deficiency and Growth Hormone Neurosecretory Dysfunction

Background: The combined growth hormone-releasing hormone and growth hormone-releasing peptide-6 (GHRH + GHRP-6) test is most potent in evaluating GH secretion. Aims: To assess its capability in children with GH deficiency and low spontaneous GH secretion (GH neurosecretory dysfunction). Methods: 35 children with GH <10 µg/l after levo-dopa/clonidine (GHD), 15 with normal provocative tests but abnormal 24-hour spontaneous GH secretion (GHND), and 20 controls (C) were given 1 µg/kg of GHRH and GHRP-6 i.v. and GH (µg/l) was measured at –15, 0, 5, 10, 15, 30, 45 and 60 min. Results: Six were nonresponders to the combined test, with significantly lower peak GH 20.7 (7.8–31.8) than C and the rest of the patients (responders). Peak GH was similar between prepubertal (PP) controls 167 ± 88, GHD 202 ± 110 and GHND 155 ± 83. Pubertal (P) controls had higher peak GH 328 ± 149 than P-GHD 203 ± 105 and P-GHND 186 ± 105. While P-C had higher peak GH than PP-C, PP and P children had similar responses within the GHD and GHND groups. Conclusions: The GHRH + GHRP-6 test detects children with severe GH insufficiency. Patients with GHD respond similarly to those with GHND, indicating a possible hypothalamic GH neuroregulatory dysfunction in GHD. Responders to the combined test may be eligible for treatment with a synthetic GH secretagogue.

Evaluation of Semen Quality, Endocrine Profile and Hypothalamus-Pituitary-Testis Axis in Male Patients With Homozygous β-Thalassemia Major

The endocrine profile, hypothalamus-pituitary-testis axis and semen quality were evaluated in male patients with homozygous beta-thalassemia major. A total of 168 male patients 18 years or older with homozygous beta-thalassemia major were enrolled in the study and 84 healthy age matched male volunteers served as controls. All subjects provided a medical history and underwent physical examination and routine semen analysis. Two blood samples were drawn from each participant at 20-minute intervals to determine the resting levels of certain hormones, including luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, estradiol, insulin-like growth factor-1 and insulin like growth factor binding protein-3. The hypothalamus-pituitary-testis axis was also assessed using the luteinizing hormone-releasing hormone test. The prevalence of hypogonadotropic hypogonadism was 76.2% (128 patients). Of the studied patients with homozygous beta-thalassemia major 75 (44.6%) were short. Compared with normal controls the patients with homozygous beta-thalassemia major had lower serum luteinizing hormone, follicle-stimulating hormone, insulin-like growth factor-1, insulin-like growth factor-1 binding protein-3 and testosterone. In addition, there were decreased luteinizing hormone and follicle-stimulating hormone responses to luteinizing hormone-releasing hormone in patients with homozygous beta-thalassemia major compared to those in normal controls. Total sperm count, sperm motility and percent normal sperm morphology were lower in patients with homozygous beta-thalassemia major than in controls. Most subjects with beta-thalassemia major have hypogonadotropic hypogonadism state, impairment fertility and growth retardation. Further studies are warranted to better clarify the causes and consequences of hypogonadotropic hypogonadism in patients with homozygous beta-thalassemia major.

Two novel GnRHR gene mutations in two siblings with hypogonadotropic hypogonadism

Mutations in the gonadotropin-releasing hormone receptor (GnRHR) gene are the cause of isolated hypogonadotropic hypogonadism (HH). We describe the molecular investigations of the GnRHR gene in two siblings affected by HH and their clinical course. The female was referred at age 14 for pubertal delay with no secondary sexual signs, whereas the male had been followed since prepuberty. Hormonal evaluation showed very low levels of gonadotropins, luteinizing hormone-releasing hormone test (LHRH test) and sexual steroids in both patients, suggesting a possible defect in the mechanism of action of the GnRH gene on its receptor. The GnRHR gene of the two siblings and their parents were analyzed by PCR followed by direct sequencing. Two new single nucleotide substitutions resulting in the T104I and the Y108C substitutions in the first extracellular loop (ECL1) were identified in both siblings. The molecular analysis confirmed the carrier status of the parents. We identified two new missense mutations in the GnRHR gene in two siblings with HH. The nature of the substitutions lying in the ECL1 involved in the ligand-receptor interaction, as well as the high conservation of the two residues in all mammalian GnRHR, are suggestive of some implications in the phenotype observed.

Persistent neonatal hypoglycaemia as a result of hypoplastic pituitary gland

An Indonesian female infant developed hypoglycaemia shortly after delivery by lower segment caesarean section. Following admission to the neonatal intensive care unit, she continued to have episodes of hypoglycaemia despite adequate glucose intake of up to a maximum of 12 mg/kg/minute. During the episodes of hypoglycaemia, repeated measurement of her blood samples revealed persistently low levels of serum insulin of &lt;2 IU/ml, serum free thyroxine of 4.78 pmol/litre, thyroid stimulating hormone of 0.31 uIU/ml and growth hormone of 0.27 mIU/litre, all suggesting a diagnosis of hypopituitarism. Empirical replacement therapy with hydrocortisone (10 mg four times daily) was started at 26 days. However, her hypoglycaemic attacks ceased only with commencement of additional hormone replacement therapy of growth hormone (0.1 mg once daily for 6 days per week) and thyroxine (50 μg once daily). The hydrocortisone dose was gradually tailed to a maintenance dose of 2.5 mg twice daily. Stimulatory tests such as adrenocorticotropic hormone and luteinizing hormone-releasing hormone tests and posterior pituitary function were not performed at that time as the infant developed Klebsiella pneumoniae and coagulase negative staphylococcus sepsis which may have affected the test results. A magnetic resonance imaging (MRI) scan of her brain at 1 month of age showed a hypoplastic pituitary gland with a shallow pituitary fossa (Figure 1). The posterior lobe of the gland was undescended, lying ectopic at the base of the third ventricle with an absent pituitary stalk (Figure 2). The rest of the MRI was normal with no associated anomalies of the midline forebrain structures. No abnormalities were detected in detailed opthalmological examination of her eyes excluding the possibility of septo-optic dysplasia. When followed up at 8 months of age, she remained well with improved hormonal profiles and normal levels of serum urea and electrolytes. Her weight, height and occipito-frontal circumference were all below the third percentile.

Effect of metformin on the growth hormone response to growth hormone–releasing hormone in obese women with polycystic ovary syndrome

Obese women with polycystic ovary syndrome (PCOS) show a marked growth hormone (GH) hyporesponsiveness to several stimuli. We aimed to evaluate the impact of insulin metabolism on the GH secretion impairment in these subjects in relation to food ingestion. Prospective clinical study. Academic research center. Nine obese women with PCOS. Metformin (1,500 mg/daily) was administered for three months. The study protocol, which was performed before and after therapy, included hormonal and lipid assays, oral glucose tolerance test (75 g), euglycemic hyperinsulinemic clamp, and growth hormone-releasing hormone (GHRH) test (50 microg/ev), both on fasting and after a standard meal. Growth hormone response to GHRH (expressed as the area under the curve) in different experimental conditions. The preprandial GH response to GHRH was not modified by the therapy, whereas a significant increase (P<.05) occurred in the postprandial GH secretion, thus resembling the response of obese normal persons. This change was accompanied by a trend towards improvement, though not statistically significant, of all the evaluated glycoinsulinemic parameters. A significant reduction in cholesterol (P<.01) and androstenedione (P<.05) and an increase in sex hormone-binding globulin (P<.05) were also achieved. These data suggest that metformin is able to affect GH secretion in obese women with PCOS, even with minimal metabolic modifications.

Hypogonadotropic hypogonadism and hematologic phenotype in patients with transfusion-dependent beta-thalassemia.

To determine the prevalence and risk factors of hypogonadotropic hypogonadism in transfusion-dependent patients with thalassemia. The authors examined 29 patients with thalassemia major aged 15 years or older. Luteinizing hormone-releasing hormone tests were performed and beta-thalassemia mutations were analyzed by direct sequencing. The prevalence of hypogonadotropic hypogonadism was 72%. Failure of puberty was observed in 5 of 11 (45%) boys and 7 of 18 (39%) girls. Arrested puberty was noted in two boys (18%) and five girls (28%). Ten girls (56%) did not menstruate, two (11%) had regular menstrual cycles, one (6%) had irregular menstrual cycles, and five (28%) developed secondary amenorrhea. Twenty-one and eight patients had the beta 0/beta 0 and beta 0/beta+ hematologic phenotypes, respectively. beta 0-thalassemia mutation alleles involved IVS II-654 (C-T), codons 41/42 (-TCTT), codons 27/28 (+C), and codons 17 (A-T). beta+-thalassemia mutations alleles were -28 (A-G) and HbE (codons 26(GAG-AAG)). Hematologic phenotype (odds ratio, 28.50; P = 0.002) was the only risk factor identified in the logistic regression analysis. In patients with thalassemia major, genetic differences may influence their susceptibility to hypogonadotropic hypogonadism, possibly as a result of differences in the amounts of blood transfused and/or their vulnerability to free radical damage. The hematologic phenotype is a main determinant of the severity of thalassemia major; hence, it may influence the need for and frequency of blood transfusion and the patient's iron-overload status.

Endocrine mechanism of action of toremifene at the level of the central nervous system in advanced breast cancer patients

To differentiate the antagonistic and agonistic effect of toremifene at the level of the hypothalamus-hypophysis axis a leutinizing hormone-releasing hormone (LHRH) test was performed during a phase II clinical trial. In 15 postmenopausal patients with advanced breast cancer, follicle-stimulating hormone (FSH) and LH release--induced by an LHRH agonist (Suprefact injection, 0.5 mg s.c.)--was monitored during a 16-week period of toremifene treatment (60 mg/day p.o.). Prolactin, estradiol, and sex hormone-binding globulin (SHBG) levels were also measured. The functional test was carried out prior to toremifene therapy and then 4, 8, 12, and 16 weeks afterward. The drug sensitized the pituitary to the action of the gonadotrophins; the LHRH-induced FSH and LH release showed a considerably increasing tendency during the toremifene therapy. Estradiol levels decreased statistically significantly and SHBG levels showed a statistically significant increase. A decreased level of prolactin is the sign of an antiestrogenic effect of toremifene on the hypophysis and, as a result, provides evidence for a direct influence of toremifene upon the pituitary. An increase in LH and prolactin release in response to the LHRH test was characteristic in the responders. According to the LHRH test, the antagonistic effect of toremifene seems to be more dominant than the concomitantly existing agonistic property. Neither clinical nor endocrinological side effects could be observed at the level of the CNS during a prolonged period of toremifene administration.