Idiopathic Hypothalamic Hypogonadism Research Articles

Physiological Characterization and Transcriptomic Properties of GnRH Neurons Derived From Human Stem Cells.

Gonadotropin-releasing hormone (GnRH) neurons in the hypothalamus play a key role in the regulation of reproductive function. In this study, we sought an efficient method for generating GnRH neurons from human embryonic and induced pluripotent stem cells (hESC and hiPSC, respectively). First, we found that exposure of primitive neuroepithelial cells, rather than neuroprogenitor cells, to fibroblast growth factor 8 (FGF8), was more effective in generating GnRH neurons. Second, addition of kisspeptin to FGF8 further increased the efficiency rates of GnRH neurogeneration. Third, we generated a fluorescent marker mCherry labeled human embryonic GnRH cell line (mCh-hESC) using a CRISPR-Cas9 targeting approach. Fourth, we examined physiological characteristics of GnRH (mCh-hESC) neurons: similar to GnRH neurons in vivo, they released the GnRH peptide in a pulsatile manner at ~60 min intervals; GnRH release increased in response to high potassium, kisspeptin, estradiol, and neurokinin B challenges; and injection of depolarizing current induced action potentials. Finally, we characterized developmental changes in transcriptomes of GnRH neurons using hESC, hiPSC, and mCh-hESC. The developmental pattern of transcriptomes was remarkably similar among the 3 cell lines. Collectively, human stem cell–derived GnRH neurons will be an important tool for establishing disease models to understand diseases, such as idiopathic hypothalamic hypogonadism, and testing contraceptive drugs.

Peripheral action of kisspeptin at reproductive tissues-role in ovarian function and embryo implantation and relevance to assisted reproductive technology in livestock: a review.

Kisspeptin (KISS1) is encoded by the KISS1 gene and was initially found to be a repressor of metastasis. Natural mutations in the KISS1 receptor gene (KISS1R) were subsequently shown to be associated with idiopathic hypothalamic hypogonadism and impaired puberty. This led to interest in the role of KISS1 in reproduction. It was established that KISS1 had a fundamental role in the control of gonadotropin releasing hormone (GnRH) secretion. KISS1 neurons have receptors for leptin and estrogen receptor α (ERα), which places KISS1 at the gateway of metabolic (leptin) and gonadal (ERα) regulation of GnRH secretion. More recently, KISS1 has been shown to act at peripheral reproductive tissues. KISS1 and KISS1R genes are expressed in follicles (granulosa, theca, oocyte), trophoblast, and uterus. KISS1 and KISS1R proteins are found in the same tissues. KISS1 appears to have autocrine and paracrine actions in follicle and oocyte maturation, trophoblast development, and implantation and placentation. In some studies, KISS1 was beneficial to in vitro oocyte maturation and blastocyst development. The next phase of KISS1 research will explore potential benefits on embryo survival and pregnancy. This will likely involve longer-term KISS1 treatments during proestrus, early embryo development, trophoblast attachment, and implantation and pregnancy. A deeper understanding of the direct action of KISS1 at reproductive tissues could help to achieve the next step change in embryo survival and improvement in the efficiency of assisted reproductive technology.

The prolactin response to TRH and domperidone does not differentiate male hypothalamic hypogonadism and constitutional delay of puberty.

In order to test whether prolactin response to challenge with TRH and domperidone, dopamine receptor antagonist, is diagnostic for idiopathic hypothalamic hypogonadism (IHH) we studied 8 normal controls, 9 subjects with delayed sexual development and 6 patients with IHH. TRH test (200 micrograms i.v. bolus) and domperidone (10 mg i.v. bolus) were given on two different days. Prolactin (RIA-Biodata) was determined in blood samples during the test. The basal value of prolactin in subjects with delayed puberty and healthy controls did not differ from basal values of prolactin in patients with IHH. The peak elevation of prolactin after TRH in subjects with delayed puberty and healthy controls did not differ from that in patients with IHH. After successful treatment of one patient with IHH (Kallmann's syndrome) with pulsatile s.c. LHRH we did not find any change in the response of prolactin to TRH challenge after 1, 3 and 6 months of treatment, while prolactin response to domperidone increased. Prolactin responses to TRH and domperidone are not differential for the early diagnosis of IHH. Successful treatment of a patient with IHH did not change the response of prolactin to TRH, but increased prolactin response to domperidone possibly due to altered steroid milieu.

Changes in anterior pituitary response in patients with idiopathic hypothalamic hypogonadism caused by pulsatile GnRH therapy and testosterone replacement.

This study evaluated in male patients with idiopathic hypothalamic hypogonadism the effect of pulsatile GnRH therapy or testosterone replacement on the response of all anterior pituitary hormones to adequate dynamic stimuli. In nine patients with idiopathic hypothalamic hypogonadism--mean age 21 +/- 1 (mean +/- SE)--a combined pituitary stimulation (CPS) with 200 micrograms TRH, 100 micrograms GnRH, 100 micrograms CRH and 100 micrograms GRH and an insulin tolerance-test (ITT) with 0.1 U insulin/kg body weight were performed. Both tests were repeated during pulsatile GnRH therapy and thereafter on testosterone replacement. Hormone levels were measured by immunometric assays. For statistical analysis the area under the curve (AUC) was used as a measure for hormone response. Testosterone levels did not differ significantly during GnRH therapy (16.6 +/- 2.1 nmol/L) and testosterone replacement (18.5 +/- 1.7 nmol/L). No significant differences were observed before and during the two treatment modalities for TSH and ACTH. PRL increase was significantly higher during GnRH therapy (AUC: 73580 +/- 8940) compared to the rise before treatment (AUC: 36161 +/- 5853; p < 0.01) and on testosterone replacement (AUC: 49995 +/- 6158; p < 0.01). The GH response to CPS and ITT was higher under testosterone replacement (AUC: 1826 +/- 353 and 1423 +/- 125) compared with the pretreatment situation (AUC: 727 +/- 115; p < 0.05 and 541 +/- 110; p < 0.01) and also more pronounced than under GnRH therapy (AUC: 1148 +/- 180 and 798 +/- 129; p < 0.05). FSH and LH after CPS rose significantly more during GnRH therapy (AUC: 864 +/- 122 and 2215 +/- 219) than before (AUC: 418 +/- 61 and 1424 +/- 277; p < 0.01) and on testosterone treatment (342 +/- 83 and 1153 +/- 323; p < 0.05). These results show that GnRH exerts a stimulatory effect on PRL secretion and may modulate GH secretion independently from sex steroids.

Pulsatile gonadotrophin releasing hormone versus gonadotrophin treatment of hypothalamic hypogonadism in males

In this study, pulsatile gonadotrophin releasing hormone (GnRH) therapy and gonadotrophin therapy were compared for male patients with idiopathic hypothalamic hypogonadism. Thirty-six patients, 19 with this condition, and 17 with Kallmann's syndrome, were included in the study. Their mean age was 21.1 +/- 3.0 years (+/- SD). They were divided into two groups of similar age, number and testicular volume. Pulsatile GnRH therapy was started with 4 micrograms GnRH s.c. every 2 h using a portable pump and gonadotrophin therapy with weekly i.m. injections of 3 x 2500 IU human chorionic gonadotrophin (HCG). After 8-12 weeks of HCG treatment, 150 IU human menopausal gonadotrophin (HMG) 2-4 times weekly were added and the dose of HCG reduced if necessary. Testosterone concentrations increased significantly more (P < 0.03) in the gonadotrophin group than in the GnRH group (22.5 +/- 8.1 versus 16.8 +/- 5.5 nmol/l). The rise in oestradiol levels was also significantly higher (P < 0.001) in the gonadotrophin group than in the GnRH group (150 +/- 70 versus 88 +/- 59 pmol/l). Five patients developed gynaecomastia during gonadotrophin therapy. An increased testicular volume (TV) occurred more rapidly (P < 0.001) and was significantly more pronounced (P < 0.001) after GnRH therapy (delta TV = 8.1 +/- 2.0 ml) than with gonadotrophins (delta TV = 4.8 +/- 1.8 ml). Sperm counts were performed in 14 patients given GnRH and in 17 patients given gonadotrophins. Ten patients given GnRH had positive sperm counts, ranging from 1.5 to 14 x 10(6) spermatozoa/ml; eight of those given gonadotrophins also developed spermatogenesis (2-26 x 10(6)/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of gonadotropin-releasing hormone and gonadotropin therapy in male patients with idiopathic hypothalamic hypogonadism

To compare pulsatile gonadotropin-releasing hormone (GnRH) therapy with gonadotropin therapy in male patients with idiopathic hypothalamic hypogonadism. Prospective study. Patients had free choice between the two forms of therapy. Patients were treated on an outpatient basis in our department. Eighteen patients of matched age (mean [+/- SD] age: 21.1 +/- 3.0 years and 23.6 +/- 7.3 years) and similar testicular volume were treated in each group. Pulsatile GnRH therapy was started with 4 micrograms GnRH subcutaneously every 2 hours using a portable pump and gonadotropin therapy with 3 x 2,500 IU human chorionic gonadotropin (hCG) weekly injected intramuscularly. After 8 to 12 weeks of hCG treatment, 150 IU human menopausal gonadotropin two to four times weekly were added. Testosterone (T) and estradiol (E2) levels increased significantly higher (T: P less than 0.03; E2; P less than 0.001) in the gonadotropin group than in the GnRH group (T: 22.5 +/- 8.1 versus 16.8 +/- 5.5 nmol/L; E2: 150 +/- 70 versus 88. +/- 59 pmol/L). Five patients developed gynecomastia during gonadotropin therapy. The rise of testicular volume was significantly more pronounced (P less than 0.001) in the GnRH group (delta testicular volume = 8.1 +/- 2.0 mL) than in the gonadotropin group (delta testicular volume = 4.8 +/- 1.8 mL). Ten patients of the GnRH and 8 of the gonadotropin group had positive sperm counts, ranging from 1.5 to 26 x 10(6) spermatozoa/mL. The latter was achieved more rapidly in the GnRH group (12 +/- 1.6 versus 20 +/- 2.3 months: P less than 0.02). Endocrine and exocrine testicular function can be normalized by both forms of therapy. Gonadotropin therapy has more side effects. Gonadotropin-releasing hormone leads to a higher testicular volume and a more rapid initiation of spermatogenesis compared with gonadotropin therapy.

Maintenance of spermatogenesis by intranasal administration of gonadotropin-releasing hormone in patients with hypothalamic hypogonadism.

Pulsatile administration of GnRH is a new, effective therapy for idiopathic hypothalamic hypogonadism. This therapy requires a computerized pump to deliver GnRH intermittently or repetitive single injections each day. In order to simplify this mode of therapy, we first administered hCG to two of three patients to stimulate Leydig cells, and followed this by pulsatile sc administration of GnRH in all three patients. After induction of spermatogenesis, GnRH was administered intranasally, 200 micrograms every 2 h for 8 doses daily. In all patients treated, normal spermatogenesis was maintained by nasal administration of GnRH over a period of 90, 100, and 181 days, respectively. After this period the treatment was arbitrarily discontinued.

Differentiation of male hypogonadotropic hypogonadism and constitutional delay of puberty by pulsatile administration of gonadotropin-releasing hormone.

It is not possible to differentiate reliably between male idiopathic hypothalamic hypogonadism (HH) and severe constitutional delay of puberty (CD) on the basis of a standard GnRH bolus test (GBT) or other known endocrine or clinical parameters. Therefore, we studied the response of 17 hypogonadal men, 8 with a diagnosis of HH (age, 15.5-41; bone age, 12.5-19 yr; testes, 1-4 ml) and 9 with CD (age, 14.5-20; bone age, 11-15 yr, testes, 2-10 ml) to pulsatile GnRH stimulation. Basal and peak LH and FSH levels after a single dose of GnRH greatly overlapped between the two groups. In each patient, a spontaneous nocturnal plasma profile of LH and FSH, sampled every 20 min, was followed by a pulsatile GnRH stimulation (5 micrograms iv every 90 min) via a portable minipump for 36 h. Before and after this pulsatile GnRH stimulation, a GBT (60 micrograms/m2 iv) was performed and plasma LH, FSH, testosterone, androstenedione, and dehydroepiandrosterone sulfate were measured. Pulse analysis revealed 0-5 spontaneous nocturnal LH peaks in the CD patients but only one in all of the HH patients. During the 36 h of pulsatile GnRH, mean LH and FSH levels were significantly higher (P less than 0.0001) than during the spontaneous nocturnal profile in all patients (except 1 from each group for LH). The GBT after pulsatile stimulation caused significantly higher (P less than 0.001) LH increments in CD than in HH patients, with no overlap between the two groups (range, 4.1-15.6 in CD vs. 0.8-2.4 mIU/ml in HH). Plasma testosterone rose significantly (P less than 0.01) during pulsatile GnRH from 67 to 155 ng/dl (median) in the CD men, but did not change in the HH group (21 to 22.5 ng/dl). Plasma androstenedione and dehydroepiandrosterone sulfate did not rise in either group. We conclude that, in contrast to other parameters investigated so far, the LH increment in the second GBT after 36 h of pulsatile GnRH allows clear-cut differentiation between CD and HH. These results indicate significantly lower pituitary LH reserve in patients with permanent HH after short term priming of the pituitary by pulsatile GnRH administration.