Phenotypic characterisation of mice with exaggerated and missing LH/hCG action

In order to study the physiology and pathophysiology of gonadotrophin action, we have produced transgenic (TG) mice overexpressing human chorionic gonadotrophin (hCG) alpha and beta subunits (hCG+ mice) and knockout (KO) mice for the luteinising hormone receptor (LHR; LuRKO mice). The two extremes in LH function, i.e. strong LH/hCG stimulation and total blockade of this action, confirm numerous earlier concepts about LH function, but they also reveal new aspects about gonadal function during excessive LH production and in the absence of this trophic stimulus. The purpose of this review is to summarise the key findings on these two genetically modified mouse models.

[Hypogonadism due to LH deficiency]

A 30-year-old man was investigated for delayed puberty and infertility. These investigations showed a complete absence of circulating luteinizing hormone (LH). Genetic studies revealed a missense mutation in the LHbeta gene (G36D). This mutation disrupts a vital cystine knot motif and abrogates the heterodimerization and secretion of LH. Treatment with hCG was instituted, which led to arise in testosterone and improvement in spermatogenesis. After in vitro fertilization the patient had a son who was heterozygous for the G36D mutation. A second patient with similar clinical and biological presentation has been explored. A non-frame shift deletion of 3 base-pairs was discovered at position 20 which led to the deletion of a lysine residue. The proband and his prepubescent brother were homozygotic for this mutation. These cases illustrate the important physiological role of LH in male sexual maturation and fertility.

Mutations along the pituitary-gonadal axis affecting sexual maturation: novel information from transgenic and knockout mice

During the last 10 years, numerous activating and inactivating mutations have been detected in the genes encoding the two gonadotrophins, luteinising hormone (LH) and follicle-stimulating hormone (FSH), as well as their cognate receptors (R), LHR and FSHR. Because activation of the hypothalamic-pituitary-gonadal axis is a crucial event in the onset and progression of puberty, mutations affecting gonadotrophin action have major influence on this developmental process. Many of the phenotypic effects observed have been expected on the basis of the existing information about gonadotrophin action (e.g. delayed puberty), but also many unexpected findings have been made, including the lack of phenotype in women with activating LHR mutations, and the discrepancy in phenotypes of men with inactivating mutations of FSHbeta (azoospermia and infertility) and FSHR (oligozoospermia and subfertility). Some of the possible mutations, such as inactivating LHbeta and activating FSHR mutations in women, have not yet been detected. Genetically modified mice provide relevant phenocopies for the human mutations and serve as good models for studies on molecular pathogenesis of these conditions. They may also predict phenotypes of the mutations that have not yet been detected in humans. We review here briefly the effects of gonadotrophin subunit and receptor mutations on puberty in humans and contrast the information with findings on genetically modified mice with similar mutations.

Endocrine manifestations of craniopharyngioma

RATIONALE

Due to the proximity of craniopharyngiomas to the hypothalamus and pituitary gland, most children and adolescents presenting with these tumors will exhibit significant endocrine dysfunction. After treatment, these impairments can become a major cause of morbidity and mortality.

METHODS

The postoperative course of children undergoing surgery for craniopharyngioma is reviewed.

CONCLUSION

Even if hormone levels seem to be adequate in the short term after treatment, deficiencies may develop over years and need to be monitored closely.

Voice changes after androgen therapy for hypogonadotrophic hypogonadism

OBJECTIVES/HYPOTHESIS

Males with isolated hypogonadotropic hypogonadism (IHH) fail to undergo normal sexual development, including the lack of masculinization of the larynx. The objective of this study was to measure the mean vocal fundamental frequency (MF0) in IHH patients and determine the impact of androgen treatment. An additional aim was to compare the MF0 between IHH patients and controls.

STUDY DESIGN

Prospective observational study.

METHODS

Twenty-four patients with IHH were identified along with 30 normal males and females. Voice recordings were obtained on all subjects. Androgen therapy was administered to the IHH patients. The MF0 and serum sex hormone levels were measured before treatment and at intervals during therapy. These results were compared with the pretreatment data within the IHH group. Voice parameters were also compared between the pre- and posttreatment IHH patients and the normal males and females.

RESULTS

The MF0 in untreated IHH patients was 229 +/- 41 Hz. This was intermediate between the normal male (150 +/- 22 Hz, P < .001) and normal female patients (256 +/- 29 Hz, P < .01). After treatment, the MF0 in the IHH group decreased to 173 +/- 30 Hz (P < .0001); indeed, their posttreatment MF0 approached that of normal males (P < .08). Serum hormone levels responded to the injected testosterone, but these levels did not directly correlate with MF0.

CONCLUSIONS

MF0 in IHH patients is intermediate between normal male and female levels. After treatment with testosterone, these values approach the range of normal males. This prospective study details the impact of androgens on the larynx and vocal function in patients with IHH.

Complete Sertoli cell proliferation induced by follicle-stimulating hormone (FSH) independently of luteinizing hormone activity: evidence from genetic models of isolated FSH action

Defining the gonadal effects of FSH distinct from those of LH remains difficult. We have characterized and compared the level of Sertoli and germ cell development in three mouse models recently created to isolate FSH activity from LH effects. Two models used LH-deficient hypogonadal (hpg) mice to selectively study either pituitary-independent transgenic (tg) FSH or ligand-independent activated tg FSH receptor (FSHR(+)) expression, and the third model used LH receptor (LHR)-deficient mice to isolate and examine endogenous mouse FSH effects. Stereological evaluation revealed tg-FSH or tg-FSHR(+) activity significantly increased total Sertoli cell numbers per testis in both hpg models relative to control hpg testes. Furthermore, tg-FSH dose-dependently restored hpg Sertoli cells to wild-type (wt) (non-hpg) levels, and LHR-/- testes also exhibited wt Sertoli numbers. Spermatogonial proliferation and meiotic development were enhanced by tg-FSHR(+) or tg-FSH. Despite producing normal Sertoli numbers, isolated tg-FSH activity only increased total spermatogonia and spermatocyte populations to 57 and 44% of wt, which was comparable to spermatogonia and spermatocyte numbers observed in LHR-null testes (45 and 34% of wt). Selective FSH activity initiated round spermatid formation in all three models. However, elongated spermatid formation was detected in tg-FSH and tg-FSHR(+) hpg testes but not in LHR-/- testes, which may reflect even lower intratesticular testosterone levels in LHR-null compared with hpg testes. FSH increased round and elongated spermatid numbers in hpg testes to 16 and 6% of wt without altering intratesticular testosterone levels, but failed to produce spermatozoa demonstrating the inability of FSH to complete spermatogenesis. These findings revealed that full Sertoli cell proliferation can be accomplished by FSH activity without LH requirement, and although postnatal mitotic and meiotic germ cell development can be promoted by FSH alone, LH-mediated effects remain a critical determinant for initiating the full complement of germ cells and final stages of postmeiotic development.

[Severe postmenopausal hyperandrogenism due to an ovarian lipoid cell tumor: a case report]

The case of a 62-year-old woman with severe post-menopausal hirsutism is described. Her clinical history revealed regular menstrual periods until menopause at the age of 50, hysterectomy for fibromatosis at 58 years, non-insulin dependent diabetes mellitus, hypertension, obesity, severe hirsutism, which had developed in the previous 3 years, with a deeping of the voice. Examination showed android obesity, hypertension and severe hirsutism involving the face and the trunk. Endocrine evaluation pointed out regular adrenal function, serum total and free-testosterone in the adult male range, with normal androstenedione, DHEAS and 17OHP levels. Estradiol was slightly increased and LH and FSH were inappropriately low for her post-menopausal age. Computed tomography of the abdomen showed regular adrenal glands, and a radio-labeled cholesterol scan was negative. A further pelvic transvaginal ultrasonography revealed a small cystic formation near the right ovary and a slight increase in the size of the left ovary. The patient underwent bilateral ovariectomy. Histological examination showed a lipoid cell tumor within the left ovary. Immunohistochemical studies were positive for inhibin and cytokeratin. After surgery, serum testosterone fell to normal levels, gonadotropins increased to menopausal levels, confirming that the tumor was able to produce both LH, and FSH-inhibiting factors, and hirsutism greatly improved. Periodic hormonal tests remained normal and CT of the abdomen and pelvic ultrasonography did not show alterations at a 3 years follow-up.

Lutropin alfa: new preparation. Combined with follitropin for follicular development: no better than menotropin

(1) The reference ovarian stimulant for women with severe FSH and LH deficiency and pituitary dysfunction is menotropin (postmenopausal urinary human gonadotrophin (hMG)). (2) A recombinant LH, lutropin alfa, has now been licensed for this use, in combination with recombinant FSH (follitropin alfa or follitropin beta). The evaluation file contains no data from trials comparing the follitropin-lutropin alfa combination with menotropin. (3) Two dose-finding studies involving a total of 78 women, and a double-blind trial comparing follitropin + placebo with follitropin + lutropin alfa, have shown that 75 IU/day lutropin alfa yields satisfactory follicular development in two-thirds of women whose plasma LH concentration is below 1.2 IU/I. Efficacy has not been demonstrated in women with higher plasma concentrations of LH. Similar results have been reported with menotropin. (4) The adverse effect profile of the follitropin + lutropin alfa combination is similar to that of menotropin. The main risk is an ovarian hyperstimulation syndrome. Monitoring of plasma estradiol concentrations, pelvic ultrasound findings, and clinical state are required to avoid severe ovarian hyperstimulation. There is no evidence that the risk differs between menotropin and the follitropin + lutropin alfa combination at adjusted doses. (5) In France, the combination of follitropin alfa + lutropin alfa costs about five times more than menotropin. (6) Menotropin remains the first line ovarian stimulant for women with severe deficiency of FSH and LH.

Differentiation of adult-type Leydig cells occurs in gonadotrophin-deficient mice

During mammalian testis development distinct generations of fetal and adult Leydig cells arise. Luteinising hormone (LH) is required for normal adult Leydig cell function and for the establishment of normal adult Leydig cell number but its role in the process of adult Leydig cell differentiation has remained uncertain. In this study we have examined adult Leydig cell differentiation in gonadotrophin-releasing hormone (GnRH)-null mice which are deficient in circulating gonadotrophins. Adult Leydig cell differentiation was assessed by measuring expression of mRNA species encoding four specific markers of adult Leydig cell differentiation in the mouse. Each of these markers (3beta-hydroxysteroid dehydrogenase type VI (3betaHSD VI), 17beta-hydroxysteroid dehydrogenase type III (17betaHSD III), prostaglandin D (PGD)-synthetase and oestrogen sulphotransferase (EST)) is expressed only in the adult Leydig cell lineage in the normal adult animal. Real-time PCR studies showed that all four markers are expressed in adult GnRH-null mice. Localisation of 3betaHSD VI and PGD-synthetase expression by in situ hybridisation confirmed that these genes are expressed in the interstitial tissue of the GnRH-null mouse. Treatment of animals with human chorionic gonadotrophin increased expression of 3betaHSD VI and 17betaHSD III within 12 hours further indicating that differentiated, but unstimulated cells already exist in the GnRH-null mouse. Thus, while previous studies have shown that LH is required for adult Leydig cell proliferation and activity, results from the present study show that adult Leydig cell differentiation will take place in animals deficient in LH.

Use of GnRH agonist and human chorionic gonadotrophin tests for differentiating constitutional delayed puberty from gonadotrophin deficiency in boys

OBJECTIVES

The differentiation of constitutional delayed puberty (CDP) from gonadotrophin deficiency (GD) in boys at referral poses a difficult challenge. The effectiveness of the GnRH agonist (GnRH-a) test in distinguishing between the two conditions was evaluated and compared with findings of the GnRH and hCG stimulation tests. PATIENTS, METHODS AND DESIGN: The study sample included 32 prepubertal boys aged 14 years or older. Thirteen entered spontaneous puberty within 1 year of referral (group A) and 19 remained prepubertal (group B). All underwent the GnRH test (Relefact, Hoechst AG, 0.1 mg/m2 i.v. in one bolus), GnRH-a test (Decapeptyl, Ferring GmbH, 0.1 mg/m2 s.c.) and hCG stimulation (Chorigon, Teva, 1500 units i.m. on three alternate days) at 1-week intervals. All tests were performed at referral at 0800 h. Blood samples were collected before testing and at 30 and 60 min (GnRH test) or 4 h (GnRH-a) for LH and FSH determination, and before testing and at 4 h (GnRH-a) or on the seventh day (hCG) after stimulation for serum testosterone measurement.

RESULTS

The LH response to GnRH-a and the testosterone response to hCG stimulation were significantly higher in group A (LH, mean +/- SD 20.4 +/- 7.5 mIU/ml, range 10.8-32.6; testosterone, mean +/- SD 18.0 +/- 5.9 nmol/l, range 9.4-26, P < 0.0001) than in group B (LH, mean +/- SD 2.3 +/- 2.0 mIU/ml, range 0.7-6.9; testosterone, mean +/- SD 1.0 +/- 0.7 nmol/l, range 0.7-3.2), with no overlap between the groups. The cut-off for the LH response to GnRH-a was 8.0 mIU/ml, and for the testosterone response to hCG, 8 nmol/l. There were also significant differences between the groups in mean basal serum LH and FSH (LH, 1.1 +/- 0.5 vs. 0.6 +/- 0.2 mIU/ml, P < 0.05; FSH, 2.2 +/- 2.0 vs. 0.4 +/- 0.3 mIU/ml, P < 0.02) and their response to GnRH (LH, 11.4 +/- 4.4 vs. 2.7 +/- 1.1 mIU/ml, P < 0.0001; FSH, 5.1 +/- 3.4 vs. 2.5 +/- 2.4 mIU/ml, P < 0.0001), and mean serum testosterone level at 4 h after GnRH-a administration (1.9 +/- 1.0 vs. 0.9 +/- 0.4 nmol/l, P = 0.002), but all showed a great overlap in range. Mean age, testicular volume and basal serum testosterone levels were similar in the two groups at referral. One year later, the testicular volume of group A (5.0-12.0 ml) was significantly larger than that of group B (1.0-3.0 ml, P < 0.0001), which remained unchanged on re-examination 3.0 +/- 0.5 years later.

CONCLUSIONS

The GnRH-agonist test and the repeated-injection hCG test are reliable diagnostic tools for differentiating CDP from GD in boys.

Pituitary radiographic abnormalities and clinical correlates of hypogonadism in elderly males presenting with erectile dysfunction

The prevalence of erectile dysfunction rises rapidly with age and is a frequent complaint presented in clinical practice. Although the etiology of erectile dysfunction is multifactorial, 10-20% of evaluations demonstrate testosterone deficiency. Testosterone deficiency due to secondary hypogonadism increases with age. Despite a higher prevalence of secondary hypogonadism in the elderly, there are no studies addressing hypothalamic-pituitary structural abnormalities in elderly impotent men with testosterone deficiency. We retrospectively reviewed the records of all elderly men who presented for general outpatient evaluation of erectile dysfunction from 1996 to 1999. To obtain a cohort control population, the records of 300 patients without erectile dysfunction were also reviewed. Amongst the erectile dysfunction patients, 225 were found to be testosterone deficient (testosterone < 300 ng/dl). Of these patients, 29 were additionally diagnosed with secondary hypogonadism based on a luteinizing hormone (LH) < 13 mIU/ml. Magnetic resonance imaging (MRI) or computed tomography (CT) imaging was available and reviewed in all patients diagnosed with secondary hypogonadism. Ten per cent of these patients had hypothalamic-pituitary imaging abnormalities. The prevalence of pituitary tumors within our population was not significantly elevated compared to the previous general population studies. Small-vessel white matter disease, hyperlipidemia and history of compression fractures were significantly increased in both univariate and multivariate analysis in the erectile dysfunction group compared with the control cohort. This study does not suggest that the use of hypothalamic-pituitary imaging in the evaluation of impotence in elderly men, in the absence of clinical characteristics of other hormonal loss or sella compression symptoms, will increase diagnosis of structural hypothalamic-pituitary abnormalities over that of the general population. However, the yield may increase with very low testosterone levels. These data suggest that there is an increase in ischemic white matter disease in elderly men with hypogonadism that may reflect microvascular injury to the hypothalamic-pituitary. Furthermore, these data confirm that low testosterone is associated with hyperlipidemia in the elderly. Future studies are required to assess the role of hypogonadism and hyperlipidemia, and to determine if treatment of the hormone deficiency improves the lipid profile.

Prevalence and incidence of hypopituitarism in an adult Caucasian population in northwestern Spain

OBJECTIVE

To determine the prevalence and incidence of hypopituitarism in the general population.

POPULATION

The study population comprised an average population sample of 146,000 adult inhabitants in South Galicia (northwestern Spain). The Medical Register of the General Hospital of Vigo ensured virtually complete case ascertainment for diagnosed hypopituitarism in this sample population. Only patients residing in the study area were included. The diagnosis of hypopituitarism was based on baseline and hormonal dynamic tests.

DESIGN

The study comprised two cross-sectional surveys, the first from January to December 1992 and the second from January to December 1999, together with a longitudinal survey performed between January 1993 and December 1999.

MAIN RESULTS

In the first survey the prevalence of hypopituitarism was 29/100,000 (CI, 19.88-37.72), without sex differences. In the second survey, the prevalence observed was higher than in the first, 45.5/100,000 (CI, 34.92-56.08). In the second survey, which included almost all cases registered in the first study, the cause of hypopituitarism was a pituitary tumour in 61%, a non-pituitary tumour in 9% and a non-tumour cause in 30%. Around 50% of patients had 3-5 pituitary hormonal deficiencies, with LH/FSH being the most prevalent. Patients with tumour-induced hypopituitarism showed a tendency to suffer GH deficiency more frequently than those due to non-tumour causes. In the longitudinal study with a population of 1,020,764 people-years of observation, the average annual incidence rate of hypopituitarism was 4.21 cases/100,000 (CI, 2.95-5.47), with this incidence being similar for both sexes. The annual incidence of hypopituitarism remained stable during the study period.

CONCLUSION

We present for the first time data on the prevalence and incidence of hypopituitarism in the general adult population. These patients showed a tendency to suffer LH/FSH deficiency as the most prevalent hormone deficit. Furthermore, patients with hypopituitarism due to a tumour or its treatment showed a greater tendency to suffer GH deficiency than those with a non-tumour cause. These data may be useful for producing a rational programme for patients suffering from this condition and also for comparison with future data in our country and elsewhere in the world.

Approaches to define the role of SF-1 at different levels of the hypothalamic-pituitary-steroidogenic organ axis

Targeted gene disruption has produced knockout mice lacking the orphan nuclear receptor steroidogenic factor 1 (SF-1). These SF-1 knockout mice lacked adrenal glands and gonads, resulting in adrenocortical insufficiency and sex reversal of their internal and external genitalia. They also had impaired expression of pituitary gonadotropins and agenesis of the ventromedial hypothalamic nucleus (VMH), confirming roles of SF-1 at multiple levels of the hypothalamic-pituitary-steroidogenic tissue axis. Using the Cre-loxP system, we now have generated mice in which SF-1 is inactivated selectively in the anterior pituitary. These pituitary-specific SF-1 knockout mice were sterile and failed to exhibit sexual maturation. Histologically, their gonads were markedly hypoplastic, weighing only approximately 5% of the gonads of wild-type mice. Consistent with an important role of SF-1 in gonadotropes, there were no cells in the pituitary gland that expressed either follicle-stimulating hormone (FSH) or luteinizing hormone (LH). These pituitary-specific SF-1 knockout mice are a novel genetic model of hypogonadotropic hypogonadism and establish essential roles of SF-1 in gonadotropin expression.

The role of LH in ovarian stimulation: exogenous LH: let's design the future

Historically, follicular stimulation protocols have included both FSH and LH in an attempt to mimic the physiology of normal human folliculogenesis. However, many recent gonadotrophin administration regimens have completely eliminated LH bioactivity. The importance and the amount of LH necessary for optimal follicular stimulation has been a topic of debate. Several recent studies have added to our understanding of the actions of androgens, oestrogens, gonadotrophins, and insulin on the follicle-oocyte unit, allowing a less speculative approach. Moreover, the availability of human gonadotrophins synthesized by recombinant DNA technology and gonadotrophin-releasing hormone (GnRH) antagonists, should soon permit a precise in-vivo assessment and re-evaluation of the historical 2-cell, two-gonadotrophin hypothesis. These pharmacological tools may also provide essential insights into the physiological roles of FSH and LH in human follicular development and oocyte maturation. The recombinant gonadotrophins give clinicians the unique opportunity to tailor ovarian stimulation regimens according to the patient's medical history, in an effort both to maximize oocyte yield and to improve oocyte quality.

Hypopituitarism following traumatic brain injury and aneurysmal subarachnoid hemorrhage: a preliminary report

OBJECT

Recognition of pituitary hormonal insufficiencies after head injury and aneurysmal subarachnoid hemorrhage (SAH) may be important, especially given that hypopituitarism-related neurobehavioral problems are typically alleviated by hormone replacement. In this prospective study the authors sought to determine the rate and risk factors of pituitary dysfunction after head injury and SAH in patients at least 3 months after insult.

METHODS

Patients underwent dynamic anterior and posterior pituitary function testing. Results of the tests were compared with those of 18 age-, sex-, and body mass index-matched healthy volunteers. The 22 head-injured patients included 18 men and four women (mean age 28+/-10 years at the time of injury) with initial Glasgow Coma Scale (GCS) scores of 3 to 15. Eight patients (36.4%) had a subnormal response in at least one hormonal axis. Four were growth hormone (GH) deficient. Five patients (four men, all with normal testosterone levels, and one woman with a low estradiol level) exhibited an inadequate gonadotroph response. One patient had both GH and thyrotroph deficiency and another had both GH deficiency and borderline cortisol deficiency. At the time of injury, all eight patients with pituitary dysfunction had an initial GCS score of 10 or less and, compared with the 14 patients without dysfunction, were more likely to have had diffuse swelling, seen on initial computerized tomography scans (p < 0.05), and to have sustained a hypotensive or hypoxic insult (p = 0.07). Of two patients with SAH who were studied (Hunt and Hess Grade IV) both had GH deficiency.

CONCLUSIONS

From this preliminary study, some degree of hypopituitarism appears to occur in approximately 40% of patients with moderate or severe head injury, with GH and gonadotroph deficiencies being most common. A high degree of injury severity and secondary cerebral insults are likely risk factors for hypopituitarism. Pituitary dysfunction also occurs in patients with poor-grade aneurysms. Postacute pituitary function testing may be warranted in most patients with moderate or severe head injury, particularly those with diffuse brain swelling and those sustaining hypotensive or hypoxic insults. The neurobehavioral effects of GH replacement in patients suffering from head injury or SAH warrant further study.

Accelerated puberty and late-onset hypothalamic hypogonadism in female transgenic skinny mice overexpressing leptin

Excess or loss of body fat can be associated with infertility, suggesting that adequate fat mass is essential for proper reproductive function. Leptin is an adipocyte-derived hormone that is involved in the regulation of food intake and energy expenditure, and its synthesis and secretion are markedly increased in obesity. Short-term administration of leptin accelerates the onset of puberty in normal mice and corrects the sterility of leptin-deficient ob/ob mice. These findings suggest a role for leptin as an endocrine signal between fat depots and the reproductive axis, but the effect of hyperleptinemia on the initiation and maintenance of reproductive function has not been elucidated. To address this issue, we examined the reproductive phenotypes of female transgenic skinny mice with elevated plasma leptin concentrations comparable to those in obese subjects. With no apparent adipose tissue, female transgenic skinny mice exhibit accelerated puberty and intact fertility at younger ages followed by successful delivery of healthy pups. However, at older ages, they develop hypothalamic hypogonadism characterized by prolonged menstrual cycles, atrophic ovary, reduced hypothalamic gonadotropin releasing hormone contents, and poor pituitary luteinizing hormone secretion. This study has demonstrated for the first time to our knowledge that accelerated puberty and late-onset hypothalamic hypogonadism are associated with chronic hyperleptinemia, thereby leading to a better understanding of the pathophysiological and therapeutic implication of leptin.

Impaired adrenocorticotropin-adrenal axis in combined pituitary hormone deficiency caused by a two-base pair deletion (301-302delAG) in the prophet of Pit-1 gene

The Prophet of Pit-1 gene (PROP1) encodes a paired-like homeodomain protein, which is expressed early in pituitary gland development. When mutated, it is responsible for combined pituitary hormone deficiency (CPHD) in humans, as well as in Ames dwarf mice (df/df). Several independent mutations in the homeodomain of PROP1 have been identified as causative for the human CPHD phenotype, which has been characterized, thus far, as absence or low levels of GH, PRL, TSH, LH, and FSH. Here, we report 10 CPHD cases, 9 of which were born to consanguineous marriages occurring in a large family living in an isolated area in the Southeast of Brazil. All affected patients present complete absence of puberty and low GH, PRL, TSH, LH, and FSH associated with severe hypoplasia of the pituitary gland, as seen by MRI. All 3 exons of the PROP1 genes of these patients were sequenced. The 301-302delAG frameshift mutation was found in both alleles of each affected case. Surprisingly, we observed ACTH/cortisol insufficiency associated with the PROP1 phenotype. The patients' ages varied between 8 and 67 yr, and cortisol response impairment was identified in 5 of 6 of the older patients and in an 11-yr-old patient. Previous studies have not fully characterized patients at advanced ages, leading us to conclude that the phenotype of this PROP1 mutation includes late-onset adrenal insufficiency. We present an extensive clinical analysis of all of these patients. The presence of ACTH/cortisol deficiency in this family bearing the PROP1 301-302delAG mutation indicates the importance of a complete endocrine characterization and of life-long monitoring of PROP1 patients.

Genetics of human hypogonadotropic hypogonadism

Humans with hypogonadotropic hypogonadism (HH) manifest irreversible pubertal delay, infertility, and low serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Although the genetic basis of this condition is largely unknown, mutations have been identified in approximately 5-10% of HH patients. Mutations in the KAL gene (Kallmann syndrome) and the AHC gene (adrenal hypoplasia congenita/HH) cause X-linked recessive HH. Autosomal recessive HH may be brought about by mutations in the gonadotropin-releasing hormone receptor, leptin, and the leptin receptor genes. Isolated deficiencies of the gonadotropins FSH and LH are due to corresponding beta-subunit genes. PROP1 gene mutations lead to combined pituitary deficiency, and HESX gene mutations result in septo-optic dysplasia, both of which include HH. These identified gene mutations advance our understanding of normal hypothalamic-pituitary-gonadal function.

Impaired cardiac performance in elderly patients with growth hormone deficiency

Several evidences indicate that GH and/or insulin-like growth factor I (IGF-I) are involved in the regulation of cardiovascular function. In patients with childhood and adulthood-onset GH deficiency (GHD), the impairment of cardiac performance is manifest primarily as a reduction in the left ventricular (LV) mass (LVM), inadequacy of LV ejection fraction both at rest and at peak exercise, and abnormalities of LV diastolic filling. No study has been reported to date in elderly GHD patients that investigated cardiac function. In particular, it is unknown whether cardiac function is modified in accordance with patients' age as a physiological response to aging, as in normal subjects the rate and extent of LV filling are reduced with age. This study was designed to evaluate heart morphology and function, by echocardiography and equilibrium radionuclide angiography, respectively, in rigorously selected elderly patients with GHD but without evidence of other complications able to affect cardiac performance. Eleven patients with hypopituitarism (6 men and 5 women, aged 60-72 yr) and 11 sex- age- and body mass index-matched healthy subjects entered this study. None of the patients and controls presented with or had previously suffered from other concomitant diseases, such as diabetes mellitus, coronary artery diseases, long-standing hypertension, and hyperthyroidism, which could affect cardiac function. All patients had been previously operated on via the transsphenoidal and/or transcranic route for nonfunctioning pituitary adenoma, meningioma, or craniopharyngioma, and 6 of them had been irradiated. Eight patients had FSH/LH insufficiency, 5 had TSH insufficiency, and 6 had ACTH insufficiency, appropriately replaced. All subjects were tested with the combined arginine plus GHRH test showing a GH response below 9 microg/L. No significant difference was found in plasma IGF-I levels (49.2 +/- 8.5 vs. 71.8 +/- 7.5 microg/L) between patients and controls. However, IGF-I levels were lower than the normal range in 8 patients and 3 controls. Interventricular septum thickness (9.1 +/- 0.2 vs. 9.1 +/- 0.2 mm), LV posterior wall thickness (9.1 +/- 0.2 vs. 9.0 +/- 0.2 mm), and LVM after correction for body surface area (97.6 +/- 1.8 vs. 99.9 +/- 1.5 g/m2) were similar in patients and controls. Similarly, the LV ejection fraction at rest was similar in patients and controls (57.1 +/- 2% vs. 63.2 +/- 2.5%; P = NS), and it was normal (> or = 50%) in all controls and in 10 of 11 patients. By contrast, the LV ejection fraction at peak exercise was markedly depressed in elderly GHD patients compared to age-matched controls (51 +/- 2.5% vs. 73.3 +/- 3%; P < 0.001). A normal response (> or = 5% increase compared to basal value) of LV ejection fraction at peak exercise was found in 8 controls (72.7%) and in 2 of 11 patients (18.2%). No difference was found in the peak rate of LV filling, whether peak filling rate was normalized to end-diastolic volume (2.5 +/- 0.2 vs. 2.6 +/- 0.2 end-diastolic volume/s) or stroke volume (4.3 +/- 0.3 vs. 4.0 +/- 0.3 stroke volume/s), between patients and controls. Finally, exercise duration was significantly shorter in elderly GHD patients than in age-matched controls (7.2 +/- 2.1 vs. 9.1 +/- 0.2 min; P < 0.01). In the patient group, the GH peak after arginine plus GHRH test was significantly correlated with the LV ejection fraction at rest (r = 0.822; P < 0.01), whereas IGF-I was significantly correlated with the peak rate of LV filling whether the peak filling rate was normalized to end-diastolic volume (r = -0.863; P < 0.001) or stroke volume (r = -0.616; P < 0.05) or expressed as the ratio of peak filling rate to peak ejection fraction rate (r = -0.736; P < 0.01). Disease duration was significantly correlated with heart rate at peak exercise (r = 0.614; P < 0.05) and with systolic and diastolic blood pressures both at rest (r = 0.745; P < 0.01 and r = 0.650; P < 0.05) and at peak exercise (r = 0.684; P < 0.05 and r =

[Diagnosis and treatment of hypogonadotropism in males and females]

Hypogonadotropic hypogonadism is the consequence of FSH and LH deficiency leading to testicular or ovarian dysfunction. The diagnosis should be considered when there is a complete absence of pubertal development in both sexes. Hypogonadotropism, that occurs after puberty, is revealed by secondary amenorrhea in women, decreased libido in men. The hormonal diagnosis is easy in the complete forms with usually undetectable plasma LH, FSH and sex steroid levels. In the partial forms, plasma gonadotropin levels may be in the low normal range with slightly decreased plasma sex steroid levels. Gonadotropin deficiency may be isolated, congenital and of genetic origin. In acquired forms, panhypopituitarism and mass lesions of the hypothalamic pituitary sites must be diagnosed by magnetic resonance imaging and hormonal testing. Treatment requires only substitution when fertility is not sought. In the treatment of infertility, the use of pulsatile modes of GnRH administration is remarkably successful in women, as well as exogenous gonadotropins in both sexes.

"Hot spot" in the PROP1 gene responsible for combined pituitary hormone deficiency

As pituitary function depends on the integrity of the hypothalamic-pituitary axis, any defect in the development and organogenesis of this gland may account for a form of combined pituitary hormone deficiency (CPHD). Although pit-1 was 1 of the first factors identified as a cause of CPHD in mice, many other homeodomain and transcription factors have been characterized as being involved in different developmental stages of pituitary gland development, such as prophet of pit-1 (prop-1), P-Lim, ETS-1, and Brn 4. The aims of the present study were first to screen families and patients suffering from different forms of CPHD for PROP1 gene alterations, and second to define possible hot spots and the frequency of the different gene alterations found. Of 73 subjects (36 families) analyzed, we found 35 patients, belonging to 18 unrelated families, with CPHD caused by a PROP1 gene defect. The PROP1 gene alterations included 3 missense mutations, 2 frameshift mutations, and 1 splice site mutation. The 2 reported frameshift mutations could be caused by any 2-bp GA or AG deletion at either the 148-GGA-GGG-153 or 295-CGA-GAG-AGT-303 position. As any combination of a GA or AG deletion yields the same sequencing data, the frameshift mutations were called 149delGA and 296delGA, respectively. All but 1 mutation were located in the PROP1 gene encoding the homeodomain. Importantly, 3 tandem repeats of the dinucleotides GA at location 296-302 in the PROP1 gene represent a hot spot for CPHD. In conclusion, the PROP1 gene seems to be a major candidate gene for CPHD; however, further studies are needed to evaluate other genetic defects involved in pituitary development.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion. The pituitary is usually hypoplastic. In this report we describe a consanguineous family (the parents are first cousins) with thirteen siblings. Of the ten living siblings, four (two males and two females) have panhypopituitarism with severe growth failure. They had evidence of growth hormone, prolactin and gonadotropin deficiencies and developed central hypothyroidism late in life. ACTH secretion was normal. Bone age was retarded and dual-photon bone densitometry indicated severe osteoporosis. Combined provocative tests for pituitary hormones indicated blunted responses for GH, LH, FSH and a modest rise in serum PRL and TSH. A clonidine-test failed to induce pituitary GH response. A corticotropin-releasing factor (CRF) provocative test was conducted after 6 months without the use of prednisone with a normal ACTH response after CRF in the affected sibling. Plasma IGF-I and IGF-BP3 were below normal levels. Serum E2 (females) and serum testosterone (males) levels were very low. MRI evaluation of the pituitary indicated pituitary aplasia in all subjects. The phenotype described in this kindred is different from families reported with Pit-1 mutations. However, it resembles previously published kindreds with similar clinical and biochemical findings. The relative preservation of ACTH suggests a genetic defect early in pituitary gland development.

Medical treatment for idiopathic male infertility: is it curative or palliative?

Medical treatment of disorders of sperm production and function remains an important goal despite major advances in assisted reproductive technology. Effective treatments exist for genital tract obstruction, gonadotrophin deficiency, sperm autoimmunity, coital disorders and some impairments caused by toxins or illness. However, the majority of men seen for reduced sperm production or function do not have these conditions and the empirical treatments used in the past are probably ineffective. New therapeutic approaches derived from research on the causes and mechanisms of testicular dysfunction are needed and their curative effects must be established by well-designed controlled clinical trials.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion. The pituitary is usually hypoplastic. In this report we describe a consanguineous family (the parents are first cousins) with thirteen siblings. Of the ten living siblings, four (two males and two females) have panhypopituitarism with severe growth failure. They had evidence of growth hormone, prolactin and gonadotropin deficiencies and developed central hypothyroidism late in life. ACTH secretion was normal. Bone age was retarded and dual-photon bone densitometry indicated severe osteoporosis. Combined provocative tests for pituitary hormones indicated blunted responses for GH, LH, FSH and a modest rise in serum PRL and TSH. A clonidine-test failed to induce pituitary GH response. A corticotropin-releasing factor (CRF) provocative test was conducted after 6 months without the use of prednisone with a normal ACTH response after CRF in the affected sibling. Plasma IGF-I and IGF-BP3 were below normal levels. Serum E2 (females) and serum testosterone (males) levels were very low. MRI evaluation of the pituitary indicated pituitary aplasia in all subjects. The phenotype described in this kindred is different from families reported with Pit-1 mutations. However, it resembles previously published kindreds with similar clinical and biochemical findings. The relative preservation of ACTH suggests a genetic defect early in pituitary gland development.