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.

Pituitary-directed leukemia inhibitory factor transgene causes Cushing's syndrome: neuro-immune-endocrine modulation of pituitary development

Leukemia inhibitory factor (LIF) regulates the mature hypothalamic-pituitary-adrenal axis in vivo. In vitro, LIF determines corticotroph cell proliferation and induces POMC transcription. To explore LIF action on pituitary development, transgenic mice expressing LIF driven by the pituitary glycoprotein hormone alpha-subunit (alphaGSU) promoter were generated. Transgenic mice exhibited dwarfism with low IGF-I (29 +/- 9 ng/ml vs. wild type (WT) 137 +/- 16 ng/ml; P < 0.001), hypogonadism with low FSH (0.04 +/- 0.023 ng/ml vs. WT 0.63 +/- 0.18 ng/ml; P < 0.001), and Cushingoid features of thin skin and truncal obesity with elevated cortisol levels (86 +/- 22 ng/ml vs. WT 50 +/- 14 ng/ml; P = 0.002). Their pituitary glands showed corticotroph hyperplasia, striking somatotroph and gonadotroph hypoplasia, and multiple Rathke-like cysts lined by ciliated cells. LIF, overexpressed in Rathke's pouch at embryonal day 10, diverts the differentiation stream of hormone-secreting cells toward the corticotroph lineage and ciliated nasopharyngeal-like epithelium. Thus, inappropriate expression of LIF, a neuro-immune interfacing cytokine, plays a key role in the terminal differentiation events of pituitary development and mature pituitary function.

Follitropin (FSH) deficiency in an infertile male due to FSHbeta gene mutation. A syndrome of normal puberty and virilization but underdeveloped testicles with azoospermia, low FSH but high lutropin and normal serum testosterone concentrations

We studied a man who sought medical attention at age 28 years because of infertility in both his first and second marriages. His sexual development appeared to have been normal, with normal puberty and virilization, and normal libido and sexual potency. At examination, his testicles were small and soft; otherwise he had a normal physical appearance. Evaluations revealed azoospermia, undetectable in serum before and after 100 microg of intravenously administered gonadotrophin releasing hormone, but moderately elevated lutropin concentration with a brisk rise after gonadotrophin releasing hormone. The alpha subunit concentration was normal before and after gonadotrophin releasing hormone; that of inhibin B was very low. Analysis of the follitropin beta gene, exon 3, revealed a Cys82 --> Arg mutation (TGT --> CGT). Judging from studies of the biosynthesis of the chorionic gonadotrophin beta subunit one may conclude that inability to form the first intramolecular disulphide bond in the follitropin beta subunit results in an abnormal tertiary structure during follitropin beta biosynthesis with extensive intracellular degradation of the products, inability to associate with the alpha subunit and defective glycosylation, as well as inability to form a biologically active hormone. This first male case of follitropin deficiency thus defines a new syndrome of male infertility.

Genetic rescue of follicle-stimulating hormone beta-deficient mice

FSH is an alpha:beta heterodimeric pituitary glycoprotein that shares a common alpha-subunit with LH and TSH. To study the role of FSH in mammalian reproduction, we have previously generated an FSH-deficient mouse model using embryonic stem (ES) cell technology by introducing a null mutation in the unique FSHbeta gene. Male mice deficient in FSH are fertile despite their small testes and reduced sperm number and motility. In contrast, FSH-deficient female mice are infertile due to a block in folliculogenesis at the preantral stage. In this set of experiments, we have rescued the mutant phenotypes of FSHbeta-deficient mice by two genetic strategies. In the type I rescue mice, we introduced into the FSHbeta-deficient background a 10-kb human FSHbeta transgene that is selectively expressed in pituitary gonadotropes. The presence of this transgene [and thus the interspecies hybrid (i.e. mouse alpha:human FSHbeta hormone)] in the background of mouse FSHbeta deficiency completely restored the testis size, sperm number, and motility defects to levels comparable to those seen in control male mice. All of the mouse FSHbeta-deficient female mice carrying this human FSHbeta transgene resumed normal folliculogenesis, were fertile and delivered normal size litters. In the type II rescue mice, human FSH (human alpha:human FSHbeta) was ectopically produced from multiple tissues in the mutant background using a mouse metallothionein-I promoter. Whereas ectopic production of human FSH completely rescued the mouse FSHbeta-deficient male mice, only 3 out of 10 mouse FSHbeta-deficient females bearing these human FSH transgenes were fertile and carried their pregnancies to term and parturition. We conclude that the resultant phenotypes due to a genetic deficiency of mouse FSHbeta can be corrected by appropriate expression of human FSH transgenes and that human FSHbeta gene regulation and function in the mouse pituitary are indistinguishable from the endogenous mouse FSHbeta gene.

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.

Susceptibility of sperm chromatin to acid denaturation in situ: a study in endogenous FSH-deprived adult male bonnet monkeys (Macaca radiata)

Acid denaturation of calf thymus DNA in vitro followed by acridine orange (AO) binding induced a 112% increase in the emission of red, a 58% decrease in green, and a consequential decrease in the ratio of green:red fluorescences from 1.7 to 0.9. This metachromatic property of AO on binding to DNA following acid denaturation was utilized to study the susceptibility of normal and ovine follicle-stimulating hormone (oFSH) actively immunized bonnet monkey spermatozoa voided throughout the year. For analyses, the scattergram generated by the emission of red and green fluorescences by 10,000 AO-bound sperm from each semen sample was divided into 4 quadrant zones representing percentage cells fluorescing high green-low red (Q1), high green-high red (Q2), low green-low red (Q3) and low green-high red. (Q4). Normal monkey sperm obtained during the months of July-December exhibited 76, 13, and 11% cells in Q2, Q3, and Q4 quadrants, respectively. However, during January-June, when the females of the species are markedly subfertile, noncycling, and amenorrhoeic, the spermatozoa ejaculated by the male monkeys exhibited 38, 39, and 23% sperm in Q2, Q3, and Q4, respectively, the differences being highly significant (p < .01-.001). FSH deprivation induced significant shifts in fluorescence emissions, from respective controls, with 39, 33, and 28% cells in Q2, Q3, and Q4, respectively, during July-December, and 15, 48, and 37% sperm in Q2, Q3, and Q4 quadrants, respectively, during January-June. It is postulated that the altered kinetics of germ cell transformations and the deficient spermiogenesis observed earlier following FSH deprivation in these monkeys may have induced the enhanced susceptibility to acid denaturation in sperm.

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.

Enhanced susceptibility of follicle-stimulating-hormone-deprived infertile bonnet monkey (Macaca radiata) spermatozoa to dithiothreitol-induced DNA decondensation in situ

Immunoneutralization of endogenous follicle-stimulating hormone (FSH) of adult male monkeys leads to oligospermia and infertility despite unchanged testosterone levels. The inability of these monkeys to impregnate despite repeated exposures to cycling females appeared to be due to abnormal alterations in the kinetics of germ cell transformations and deficient spermiogenesis. Here we investigated the stability of sperm chromatin in oFSH-immunized monkeys as a marker for spermiogenesis. The susceptibility of spermatozoa to in vitro decondensation induced by dithiothreitol (DTT, 0.05-50 mM) was studied by measuring the nuclear fluorescence of DTT-treated, ethidium bromide (EB)-stained sperm using flow cytometry. Changes in sperm morphology and binding of thiol-specific 14C-iodoacetamide (14C-IA) were also monitored under the same conditions. Sperm from the immunized monkeys decondensed at a lower concentration of DTT, bound more EB, and decondensed more extensively than those from control animals. The difference was apparent in sperm from all regions of the epididymis. Immunized monkey sperm also bound significantly more 14C-IA at all concentrations of DTT. Overall, the effective concentration of DTT required to elicit 50% of maximal decondensation (ED50) of epididymal and ejaculated sperm was significantly lower for the immunized monkeys than even the caput sperm of controls. These results suggest that FSH deprivation in monkeys results in production of sperm with limited potential for disulfide formation and reduced chromatin stability.

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.

Colony-stimulating factor-1 plays a major role in the development of reproductive function in male mice

Colony-stimulating factor-1 (CSF-1) is the principal regulator of cells of the mononuclear phagocytic lineage that includes monocytes, tissue macrophages, microglia, and osteoclasts. Macrophages are found throughout the reproductive tract of both males and females and have been proposed to act as regulators of fertility at several levels. Mice homozygous for the osteopetrosis mutation (csfm[op]) lack CSF-1 and, consequently, have depleted macrophage numbers. Further analysis has revealed that male csfm(op)/csfm(op) mice have reduced mating ability, low sperm numbers, and 90% lower serum testosterone levels. The present studies show that this low serum testosterone is due to reduced testicular Leydig cell steroidogenesis associated with severe ultrastructural abnormalities characterized by disrupted intracellular membrane structures. In addition, the Leydig cells from csfm(op)/ csfm(op) males have diminished amounts of the steroidogenic enzyme proteins P450 side chain cleavage, 3beta-hydroxysteroid dehydrogenase, and P450 17alpha-hydroxylase-lyase, with associated reductions in the activity of all these steroidogenic enzymes, as well as in 17beta-hydroxysteroid dehydrogenase. The CSF-1-deficient males also have reduced serum LH and disruption of the normal testosterone negative feedback response of the hypothalamus, as demonstrated by the failure to increase LH secretion in castrated males and their lack of response to exogenous testosterone. However, these males are responsive to GnRH and LH treatment. These studies have identified a novel role for CSF-1 in the development and/or regulation of the male hypothalamic-pituitary-gonadal axis.

[Clinical elements for the diagnosis of secretory azoospermia]

Secretory azoospermia is defined by the existence of azoospermia, normal epididymis and vesicular markers and often high but sometimes low FSH levels. Study of the past history often reveals the cause of azoospermia, which is often toxic or a side effect of medication. Clinical investigation includes assessment of the genital organs in particular the volume of the testicles. The clinical investigation must always be accompanied by a general examination. When anamnesis and clinical examination are completed, secretory azoospermia will be classed in one of the following categories: high FSH azoospermia, law FSH azoospermia, normal FSH azoospermia.

Follicular development and oocyte maturation in hypogonadotrophic women employing recombinant follicle-stimulating hormone: the role of oestradiol

Both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are required for follicle development and oestrogen production. Moreover, under normal conditions a close association between dominant follicle size and serum and intrafollicular oestradiol levels is observed. With the recent availability of human recombinant FSH (recFSH), it was possible for the first time to study effects of FSH alone, in the complete absence of endogenous or exogenous LH, on ovarian function. Recent studies applying recFSH in hypogonadotrophic women have shown convincingly that normal growth of follicles up to the preovulatory stage occurs despite extremely low oestradiol levels, in keeping with previous observations using exogenous gonadotrophins in women incapable of synthesizing oestradiol due to steroid enzyme abnormalities. Insufficient data are presently available in humans to conclude whether or not oocyte quality is compromised under these circumstances. It should, however, be realized that sufficient oestradiol levels are required for fertilization in vivo. Therefore LH, or human chorionic gonadotrophin (HCG), should be added to stimulation protocols in hypogonadotrophic individuals. These observations may also be relevant for monitoring of ovarian response during recFSH therapy, especially when combined with gonadotrophin-releasing hormone agonists for ovarian hyperstimulation for in-vitro fertilization.

Clinical manifestations of genetic defects affecting gonadotrophins and their receptors

Raised activity of the LH axis caused by activating mutations of LH receptor gene presents with precocious puberty in boys, analogous to the presentation of LH secreting pituitary adenomas (Faggiano et al., 1983; Ambrosi et al., 1990). LH "hyperactivity' in females appears to have no effect. Hyperactivity of the FSH axis caused by activating mutations of the FSH receptor gene might parallel the presentation of FSH secreting pituitary adenomas with Sertoli cell hypertrophy in men (Heseltine et al., 1989) or reversible premature ovarian failure in women (Moses et al., 1986; Okuda et al., 1989). Indeed the first such case to be described is a male who maintained testicular volume and fertility in the absence of gonadotrophins (Gromoll et al., 1996). Female precocious puberty may require hyperactivity of both gonadotrophin axes because of the "two-cell' arrangement required for ovarian oestrogen production. Mutations of the Gs alpha-subunit gene can mimic this situation in some women with the McCune-Albright syndrome (Malchoff et al., 1994). Lack of LH activity caused by defects in the LH beta molecule causes infertility in men and that resulting from inactivating mutations of the LH receptor gene causes Leydig cell agenesis in men while ovarian development in females is relatively normal. Lack of FSH activity caused by defects in the FSH beta caused infertility in a female, and that caused by inactivating mutations of the FSH receptor gene causes ovarian dysgenesis in women but only variable depression of spermatogenesis in men. Incidentally, this categorization of reproductive disorders may also be applied to the TSH axis. Pituitary adenomas and activating mutations of the TSH receptor gene (Parma et al., 1993) cause hyperthyroidism and TSH beta gene defects (Hayashizaki et al., 1989) and inactivating mutations of the TSH receptor gene (Sunthornthepvarakul et al., 1995) cause hypothyroidism. To complete the analogy with thyroid disorders, it is curious that despite structural similarities with the TSH receptor, neither LH nor FSH receptor autoantibodies have a prominent role in ovarian pathophysiology (Moncayo et al., 1989; Van Weissenbruch et al., 1991; Simoni et al., 1993). Complete gonadotrophin resistance is likely to be very rare, however, so what are we likely to find in partial gonadotrophin resistance? Might the "resistant ovary syndrome' come right in the end, with corresponding minor FSH receptor mutations? Experience with insulin and androgen resistance syndromes suggests that such a scenario is unlikely. Insulin receptor gene mutations are found in extreme Type A insulin resistance but not in moderate forms of insulin resistance (O'Rahilly et al., 1991). Androgen receptor gene mutations are found in nearly all cases of complete androgen insensitivity but rarely in partial forms (Patterson et al., 1994). Mild resistance to hormone action is rarely detectable in relatives who are heterozygous for receptor mutations which are inherited in a recessive pattern. It seems unlikely therefore, that individuals heterozygous for inactivating receptor mutations will manifest symptoms of reproductive disorders and account for common conditions. Thus, while mutation analysis provides new insights into the gender specific role of the gonadotrophins the cause of early gonadal failure in the majority of individuals remains a mystery.

Use of the gonadotropin-releasing hormone agonist triptorelin in the diagnosis of delayed puberty in boys

To differentiate gonadotropin deficiency from delayed puberty in teenage boys, 0.1 mg/m2 of triptorelin, a gonadotropin-releasing hormone agonist, was administered subcutaneously at 4 AM. Serum gonadotropins and testosterone levels were determined at baseline and 4 hours after the injection. The increase in blood gonadotropin and testosterone levels was significantly greater in patients with delayed puberty than in those with gonadotropin deficiency.

Chronic neuroendocrinological sequelae of radiation therapy

A variety of neuroendocrine disturbances are observed following treatment with external radiation therapy when the hypothalamic-pituitary axis (HPA) is included in the treatment field. Radiation-induced abnormalities are generally dose dependent and may develop many years after irradiation. Growth hormone deficiency and premature sexual development can occur following doses as low as 18 Gy fractionated radiation and are the most common neuroendocrine problems noted in children. Deficiency of gonadotropins, thyroid stimulating hormone, and adrenocorticotropin are seen primarily in individuals treated with > 40 Gy HPA irradiation. Hyperprolactinemia can be seen following high-dose radiotherapy (> 40 Gy), especially among young women. Most neuroendocrine disturbances that develop as a result of HPA irradiation are treatable; patients at risk require long-term endocrine follow-up.

Four patients with polyendocrinopathy with associated pituitary hormone deficiency

Four cases of polyglandular endocrine disorders associated with pituitary hormone secretion failure are reported. Three of them had both insulin dependent diabetes mellitus (IDDM) and Hashimoto's disease. Each of these patients (cases 1-3) showed isolated deficiency of ACTH, TSH or gonadotropin, respectively. Another patient (case 4) had both Hashimoto's disease and isolated ACTH deficiency. Anti-pituitary antibody to AtT-20 cells was detected in case 1. Serum gamma-globulins from patients 1 and 4 attenuated corticotropin releasing hormone-induced ACTH release in monolayer cultured rat anterior pituitary cells. Gamma-globulins from patients 1 and 2 decreased baseline TSH release but stimulated baseline prolactin release in pituitary cell cultures. It is possible that pituitary hormone deficiency in these patients may be caused by autoimmune disorders.

Serum immunoreactive inhibin levels in polycystic ovarian disease (PCOD) and hypogonadotropic amenorrhea

To evaluate the physiological significance of inhibin in various types of amenorrhea, serum immunoreactive (IR)-inhibin levels were measured and compared with those in normal cycling women. Amenorrheic women were as follows: (1) 23 women with PCOD, 11 women with hypogonadotropic amenorrhea (HA, n = 23) and 11 women with regular menstrual cycles. Women with HA were further divided into 2 groups according to the presence or absence of withdrawal bleeding (WDB) after progesterone administration. HA with WDB was categorized as HA1, while HA without as HA 2. Serum IR-inhibin levels in women with PCOD were significantly higher than those in HA 2 and normal women at days 2 to 5 from the onset of menstruation and significantly lower than those in normal women in the mid-luteal phase. A significant positive correlation was obtained between IR-inhibin and FSH in HA 2 (r = 0.681) and HA 1 (r = 0.658), but no significant correlation between these two hormones in PCOD and normal women. These results indicated that basal IR-inhibin levels vary with types of amenorrhea. High IR-inhibin levels in PCOD patients suggest that inhibin plays a part in the discordant gonadotropin secretion in these patients.

Impaired growth hormone secretion in patients operated for pituitary adenomas

The frequency of growth hormone (GH) deficiency in patients operated for pituitary neoplasms of various size and type was investigated using the insulin tolerance test. 45 patients were included in the study. 20 of the patients had a non-hormone secreting pituitary neoplasm, 9 had GH-, 6 ACTH-, 7 prolactin secreting adenomas and 3 had a craniopharyngeoma. Complete endocrinological examination was obtained in all patients after pituitary surgery. Apart from patients operated for GH secreting adenomas, GH deficiency was very common after pituitary surgery (92%), even in patients operated for small lesions. Among the 45 patients LH/FSH deficiency was found in 33%, ACTH in 33%, TSH in 18% and ADH deficiency in 9% of the patients. In this study, impaired GH secretion was found to be independent of the size of the tumors and was present in nearly all patients after pituitary surgery (with exception of GH secreting adenomas). Deficiencies of other pituitary hormones were predominantly observed after surgery for large tumors.

Usefulness of sequential urinary follicle-stimulating hormone and luteinizing hormone measurements in the diagnosis of adolescent hypogonadotropism in males

FSH and/or LH deficiency in the second decade of life remains difficult to diagnose with testing at a single point in time because of the partial lack of hormone as well as the dynamic and inherently variable aspects of the pubertal process. A longitudinal study of gonadotropin excretion, therefore, was carried out in 78 normal boys and 157 male patients, aged 10-28 yr, with relative or absolute deficiencies of FSH and/or LH. Seven hundred and fifty-five timed urine samples were extracted with acetone, concentrated, and subjected to RIA. The results from patient groups with multiple tropic hormone deficiencies or isolated gonadotropin deficiency were clearly different from those of normal boys and individuals with constitutional delay in puberty. However, multiple samples obtained over a 2-yr period and, in selected cases, until the late teenage years may be required to diagnose gonadotropin deficiency in some patients, even using stringent predictive modeling criteria.

Isolated deficiency of follicle-stimulating hormone in man: a case report and literature review

A 34-year-old male patient was studied because of primary infertility. He was a normally virilized man with normal potency, habitus, and sense of smell. The testes were of normal consistency and volume. Semen analysis showed azoospermia. The baseline serum concentrations of luteinizing hormone (LH) were normal, but those of follicle-stimulating hormone (FSH) were undetectable. After stimulation with gonadotrophin-releasing hormone (GnRH), 100 micrograms, iv, the response of LH was normal, whereas the rise in FSH levels was minimal. The administration of clomiphene citrate (100 mg/day for 21 days) increased LH levels, but FSH levels remained low. Serum concentrations of testosterone and estradiol were normal. Baseline serum levels of thyrotrophin, prolactin, growth hormone, corticotrophin and cortisol were also normal. The patient refused testicular biopsy and treatment with purified human FSH. Our results suggest a possible defect for FSH production at the pituitary level.