Molecular pharmacology of gonadotropins

Human chorionic gonadotropin-based clinical treatments for infertile men with non-obstructive azoospermia

Spermatogenesis is primarily controlled by follicle-stimulating hormone and luteinizing hormone-driven testosterone. Luteinizing hormone acts on the Leydig cells, stimulating steroid production, predominantly testosterone, and activating critical inter-related spermatogenesis regulatory pathways. Despite evidence that exogenous gonadotropins containing luteinizing hormone activity, particularly human chorionic gonadotropin, can effectively restore spermatogenesis in azoospermic males with hypogonadotropic hypogonadism, the use of these drugs to treat other forms of non-obstructive azoospermia is the subject of an ongoing debate. In this review, we delve into the molecular properties and functions of human chorionic gonadotropin in spermatogenesis regulation and explore available preparations for therapeutic use. We examine the evidence regarding the effectiveness of human chorionic gonadotropin in treating infertility in men with pre-testicular or testicular non-obstructive azoospermia and, additionally, identify the main areas for future research. Our review highlights the critical role of luteinizing hormone activity in spermatogenesis and emphasizes the potential of human chorionic gonadotropin in treating male infertility. The variation in the characteristics of patients with non-obstructive azoospermia underscores the importance of assessing hormonal profiles when contemplating hormonal treatment for these patients. A novel stratification of male infertility patients, the APHRODITE criteria, which considers clinical and laboratory indicators, may assist in identifying individuals who could benefit from human chorionic gonadotropin therapy. While accumulating evidence suggests promising venues for pharmacological treatment in male infertility, including non-obstructive azoospermia, further research is required to completely elucidate the mechanisms underlying the effects of exogenous gonadotropins with luteinizing hormone activity on sperm production and to establish the most effective dosages and treatment durations.

Use of chorionic gonadotropins during lactation to optimize postpartum sow reproductive performance: a review

Treating lactating sows with chorionic gonadotropins may allow controlling their post-weaning reproductive function, despite the occurrence of anestrous during lactation. This article reviews the potential effectiveness of treatment with both equine and human chorionic gonadotropins (eCG and hCG, respectively) during lactation on the control of estrus expression and ovulation in weaned sows. The use of 1,000 IU hCG at 24 and 48 h postpartum may induce ovulation in the treated sows, but the ovulation rate may be variable. Pregnancy rates may be improved with combined treatment after the second week of lactation with both chorionic gonadotropins: 1,500 IU eCG plus 500 - 1,000 hCG; or 1,000 IU eCG plus 1,000 IU hCG. Treatment with eCG (1,000 - 2,000 IU) at the end of lactation may result in acceptable estrus expression and ovulation rates, although with marginal benefit for pregnancy rates. The subsequent response to treatments with chorionic gonadotropins during lactation is likely influenced by the treatment period, the suckling frequency during lactation, and the boar exposure during the weaning-to-estrus interval. A better understanding of the efficiency of such steroid-free treatments is increasingly relevant due to the constraints of the use of steroid hormones in livestock reproductive management.

Perioperative growth hormone levels as an early predictor of new-onset secondary adrenal insufficiency following transsphenoidal pituitary tumor resection

OBJECTIVE

This study aims to predict new-onset secondary adrenal insufficiency (NOSAI) after transsphenoidal pituitary tumor resection surgery using perioperative growth hormone (GH) and prolactin (PRL) levels, among other factors.

METHODS

A cohort of 124 adult patients who underwent transsphenoidal resection for non-functioning pituitary adenoma, with routine perioperative glucocorticoid use, was used to develop the predictive regression model. An additional 46 patients served as the validation cohort. Generalized additive models were used to identify optimal cut-off points for the variables.

RESULTS

The GH level on postoperative day one (POD1) can be a simple predictor by implementing a cut-off point of 0.41 ng/ml. A value ≤ 0.41 ng/mL predicted NOSAI with 0.6316 sensitivity and 0.7810 specificity for the original cohort and 1.0000 sensitivity and 0.7143 specificity for the validation cohort. The multiple logistic regression model included perioperative PRL level difference, perioperative GH level difference, intraoperative cerebrospinal fluid (CSF) leakage, tumor size, and the combined effect of diabetes insipidus (DI) and relative perioperative GH level difference. The areas under the receiver operating characteristic curves were 0.9410 (original cohort) and 0.9494 (validation cohort) for the regression model.

CONCLUSION

Early morning GH level on POD1 can predict NOSAI with fair accuracy when perioperative stress dose glucocorticoid is administered. Prediction accuracy can be improved by considering CSF leakage, DI, and perioperative changes in GH and PRL in the final regression model.

Gonadotropin therapy in assisted reproduction: an evolutionary perspective from biologics to biotech

Gonadotropin therapy plays an integral role in ovarian stimulation for infertility treatments. Efforts have been made over the last century to improve gonadotropin preparations. Undoubtedly, current gonadotropins have better quality and safety profiles as well as clinical efficacy than earlier ones. A major achievement has been introducing recombinant technology in the manufacturing processes for follicle-stimulating hormone, luteinizing hormone, and human chorionic gonadotropin. Recombinant gonadotropins are purer than urine-derived gonadotropins, and incorporating vial filling by mass virtually eliminated batch-to-batch variations and enabled accurate dosing. Recombinant and fill-by-mass technologies have been the driving forces for launching of prefilled pen devices for more patient-friendly ovarian stimulation. The most recent developments include the fixed combination of follitropin alfa + lutropin alfa, long-acting FSH gonadotropin, and a new family of prefilled pen injector devices for administration of recombinant gonadotropins. The next step would be the production of orally bioactive molecules with selective follicle-stimulating hormone and luteinizing hormone activity.

Development of a homologous enzyme-linked immunosorbent assay for European sea bass FSH. Reproductive cycle plasma levels in both sexes and in yearling precocious and non-precocious males

Since the late 1980s, gonadotropins have been isolated and characterized in several fish species, but specific immunoassays for the follicle-stimulating hormone (FSH) have only been developed for a few. The present study reports the development and use of a specific and homologous competitive ELISA for measuring FSH in European sea bass (Dicentrarchus labrax) using a recombinant FSH and its specific antiserum. Recombinant European sea bass FSHβ and FSH heterodimer were produced in the methylotrophic yeast Pichia pastoris and a baculovirus expression system, respectively. Specific polyclonal antibodies, generated by rabbit immunization against recombinant FSHβ, were used at a final dilution of 1:8000. Recombinant FSH heterodimer was used to generate a standard curve and for coating of microplates (166 μg/ml). The sensitivity of the assay was 0.5 ng/ml [B(0)-2SD], and the intra- and inter-assay coefficients of variation were 2.12% (n=10) and 5.44% (n=16) (B(i)/B(0) ∼45%), respectively. A high degree of parallelism was observed between the standard curve and serially diluted plasma and pituitary samples of European sea bass. The ELISA developed was used to study the plasma FSH profiles of mature males and females during the reproductive cycle, and those of immature juvenile males under different light regimes. The analysis showed that FSH increased significantly during the intermediate stages of spermatogenesis and during vitellogenesis. Analyses in immature juvenile males showed that the continuous light photoperiod significantly reduced plasma FSH levels, and consequently, testicular growth and precocious puberty. In conclusion, the immunoassay developed has proven to be sensitive, specific and accurate for measuring European sea bass FSH, and it represents a valuable tool for future studies on the reproductive endocrinology of this species.