Pulsatile GnRH Therapy May Restore Hypothalamus-Pituitary-Testis Axis Function in Patients With Congenital Combined Pituitary Hormone Deficiency: A Prospective, Self-Controlled Trial.

Context: The effectiveness of pulsatile gonadotropin-releasing hormone (GnRH) therapy in patients with congenital combined pituitary hormone deficiency (CCPHD) has not been investigated because of the limited number of patients, as well as these patients' presumed pituitary hypoplasia, poor gonadotrophic cell reserve, and impaired gonadotrophic response to GnRH. Objective: To assess the pituitary response to pulsatile GnRH therapy in men with CCPHD. Design: Prospective, self-controlled, 3-month clinical trial. Settings: University endocrine clinic. Patients: Men with hypogonadotropic hypogonadism caused by CCPHD. Intervention: Pulsatile GnRH was administered subcutaneously for 3 months. Main outcome measures: Primary endpoints were total serum testosterone, testicular volume, and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels. Secondary endpoints included occurrence of spermatogenesis. Results: A total of 40 men with CCPHD completed the study. Of these, 60% (24 of 40) showed a good response to pulsatile GnRH treatment (response group). At 3 months, their LH and FSH levels increased to within the normal range and their testosterone levels increased to 8.67 ± 4.83 nmol/L. Of the patients in the response group, 33.3% (8 of 24) of them achieved spermatogenesis. The remaining 40% (16 of 40) of patients had a poor response to pulsatile GnRH treatment. Magnetic resonance imaging (MRI) did not reveal any correlation between pituitary response and pituitary height and/or integrity of the pituitary stalk. Conclusions: This study suggests that gonadotrophs in patients with CCPHD can exist and be functional-even with MRI evidence of pituitary hypoplasia or dysplasia. Pulsatile GnRH therapy restored pituitary-testis axis function in 60% of patients with CCPHD. These results may directly guide the clinical therapeutic choice.

[Effects of lipopolysaccharide and dexamethasone on the expression of Kisspeptin/GPR54 in mouse hypothalamus].

OBJECTIVE: To evaluate the effects of lipopolysaccharide (LPS) and dexamethasone on function of hypothalamus-pituitary-testis axis and to explore the possible underlying mechanisms. METHODS: LPS (100 µg/kg), dexamethasone (DEX, 1 mg/kg) and phosphate buffer saline (PBS) were injected subcutaneously into castrated mice (n=5 in each group) for 4 weeks. The expression of Kisspeptin and its receptor GPR54 in hypothalamus were measured by immunohistochemistry, and plasma luteinizing hormone (LH) were measured by chemiluminescence immunoassay. RESULTS: After LPS and DEX were administered for 4 weeks, the LH level in LPS group and DEX group was (1.79±0.74) U/L and (2.19±0.60) U/L, respectively, which were lower than PBS group (4.87±1.25) U/L (all P<0.01). In LPS group, after treatment, the kisspeptin immunohistochemistry index in hypothalamus was 4.2±1.1, which was lower than the control group (10.2±1.6, P<0.05). The GPR54 immunohistochemistry index in hypothalamus was 3.6±0.5, which was lower than PBS group (6.2±1.8, P<0.05). In DEX group, the expressions of kisspeptin and GPR 54 in hypothalamus did not change after treatment. CONCLUSIONS: LPS may downregulate function of hypothalamus-pituitary-testis axis through Kisspeptin/GPR54 system. Dexamethasone could suppress function of gonadal axis as well, while the underlying mechanism is still unclear.