The GnRH test in the assessment of patients with pituitary and parapituitary lesions: results of a 5-year retrospective study

Late Effects of Parasellar Lesion Treatment: Hypogonadism and Infertility

Central hypogonadism, also defined as hypogonadotropic hypogonadism, is a recognized complication of hypothalamic-pituitary-gonadal axis damage following treatment of sellar and parasellar masses. In addition to radiotherapy and surgery, CTLA4-blocking antibodies and alkylating agents such as temozolomide can also lead to hypogonadism, through different mechanisms. Central hypogonadism in boys and girls may lead to pubertal delay or arrest, impairing full development of the genitalia and secondary sexual characteristics. Alternatively, cranial irradiation or ectopic hormone production may instead cause early puberty, affecting hypothalamic control of the gonadostat. Given the reproductive risks, discussion of fertility preservation options and referral to reproductive specialists before treatment is essential. Steroid hormone replacement can interfere with other replacement therapies and may require specific dose adjustments. Adequate gonadotropin stimulation therapy may enable patients to restore gametogenesis and conceive spontaneously. When assisted reproductive technology is needed, protocols must be tailored to account for possible long-term gonadotropin insufficiency prior to stimulation. The aim of this review was to provide an overview of the risk factors for hypogonadism and infertility in patients treated for parasellar lesions and to give a summary of the current recommendations for management and follow-up of these dysfunctions in such patients. We have also briefly summarized evidence on the physiological role of pituitary hormones during pregnancy, focusing on the management of pituitary deficiencies.

[Congenital hypogonadotropic hypogonadism and Kallmann syndrome in males]

Congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS) are a group of rare disorders responsible for complete or partial pubertal failure due to lack or insufficient secretion of the pituitary gonadotropins LH and FSH. The underlying neuroendocrine abnormalities are classically divided into two main groups: molecular defects of the gonadotrope cascade leading to isolated normosmic CHH (nCHH), and developmental abnormalities affecting the hypothalamic location of GnRH neurons, but also olfactory bulbs and tracts morphogenesis and responsible for KS. Identification of genetic abnormalities related to CHH/KS has provided major insights into the pathways critical for the development, maturation and function of the gonadotrope axis. In patients affected by nCHH, particularly in familial cases, genetic alterations affecting GnRH secretion (mutations in GNRH1, GPR54/KISS1R and TAC3 and TACR3) or the GnRH sensitivity of gonadotropic cells (GNRHR) have been found. Mutations in KAL1, FGFR1/FGF8/FGF17, PROK2/PROKR2, NELF, CHD7, HS6ST1, WDR11, SEMA3A, SOX10, IL17RD2, DUSP6, SPRY4, and FLRT3 have been associated with KS but sometimes also with its milder hyposmic/normosmic CHH clinical variant. A number of observations, particularly in sporadic cases, suggest that CHH/KS is not always a monogenic mendelian disease as previously thought but rather a digenic or potentially oligogenic condition. Before the age of 18 years, the main differential diagnosis of isolated nCHH is the relatively frequent constitutional delay of growth and puberty (CDGP). However, in male patients with pubertal delay and low gonadotropin levels, the presence of micropenis and/or cryptorchidism argues strongly in favor of CHH and against CDGP. CHH/KS are not always congenital life-long disorders as initially thought, because in nearly 10 % of patients the disease seems not permanent, as evidenced by partial recovery of the pulsatile activity of the hypothalamic-pituitary-gonadal axis after discontinuation of treatment in adulthood (the so-called reversible CHH/KS). The clinical and hormonal diagnosis and the therapeutic management as well as the genetic counseling of these patients will be discussed here based on the experience acquired in our department during the past 30 years, from monitoring more than 400 patients with these rare conditions.

Clomiphene fails to revert hypogonadism in most male patients with conventionally treated nonfunctioning pituitary adenomas

OBJETIVE: To evaluate the effect of clomiphene in men with hypogonadism and conventionally treated nonfunctioning pituitary adenomas (NFPA). PATIENTS AND METHODS: Open label, single-arm, prospective trial. Nine hypogonadal men (testosterone < 300 ng/dL and low/normal LH) with previously treated NFPA. Clomiphene (50 mg/day orally) for 12 weeks. Testosterone, estradiol, LH, FSH, prolactin and erectile function were evaluated before and after 10 days, 4, 8 and 12 weeks of clomiphene treatment. RESULTS: After clomiphene treatment, testosterone and erectile function improved in only one patient. In the remaining eight patients, testosterone levels decreased whereas LH, FSH, and estradiol remained unchanged. Insulin sensitivity increased in unresponsive patients. CONCLUSIONS: Compared with hypogonadal men with prolactinomas under dopaminergic therapy, clomiphene treatment failed to restore normal testosterone levels in most patients with conventionally treated NFPA.

Non-syndromic congenital hypogonadotropic hypogonadism: clinical presentation and genotype-phenotype relationships

Congenital hypogonadotropic hypogonadism (CHH) results from abnormal gonadotropin secretion, and it is characterized by impaired pubertal development. CHH is caused by defective GNRH release, or by a gonadotrope cell dysfunction in the pituitary. Identification of genetic abnormalities related to CHH has provided major insights into the pathways critical for the development, maturation, and function of the reproductive axis. Mutations in five genes have been found specifically in Kallmann's syndrome, a disorder in which CHH is related to abnormal GNRH neuron ontogenesis and is associated with anosmia or hyposmia. In combined pituitary hormone deficiency or in complex syndromic CHH in which gonadotropin deficiency is either incidental or only one aspect of a more complex endocrine disorder or a non-endocrine disorder, other mutations affecting GNRH and/or gonadotropin secretion have been reported. Often, the CHH phenotype is tightly linked to an isolated deficiency of gonadotropin secretion. These patients, who have no associated signs or hormone deficiencies independent of the deficiency in gonadotropin and sex steroids, have isolated CHH. In some familial cases, they are due to genetic alterations affecting GNRH secretion (mutations in GNRH1, GPR54/KISS1R and TAC3 and TACR3) or the GNRH sensitivity of the gonadotropic cells (GNRHR). A minority of patients with Kallmann's syndrome or a syndromic form of CHH may also appear to have isolated CHH, but close clinical, familial, and genetic studies can reorient the diagnosis, which is important for genetic counseling in the context of assisted reproductive medicine. This review focuses on published cases of isolated CHH, its clinical and endocrine features, genetic causes, and genotype-phenotype relationships.