Hereditary abnormality of luteinizing hormone resulting in discrepant serum concentrations determined by different assays

Role of Lh polymorphisms and r-hLh supplementation in GnRh agonist treated ART cycles: A cross sectional study

STUDY OBJECTIVES

To investigate the effect of N312S polymorphism in the LHCGR gene as a predictive pharmacogenetic marker on clinical and embryological parameters and determining the need of r-hLH supplementation combine with r-hFSH in patients undergoing ART treatment.

STUDY DESIGN

In a cross-sectional study, a retrospective analysis of women (n = 553), who underwent controlled ovarian stimulation treatment protocol was conducted during the years 2012-2014. R-hFSH (Gonal-F, Merck Serono) was administered to all patients undergoing ART cycle after initiating long luteal gonadotrophin-releasing hormone (GnRH) agonist down-regulation. R-hLH was supplemented based on P.C. Wong criteria. N312S genotype was determined using sequencing methodology. The mean r-hFSH, r-hLH doses, total number of oocytes, cleavage rates of embryos and clinical pregnancy were recorded. The association between the r-hLH supplementation and LHCGR N312S polymorphism and clinical pregnancy rates was determined using regression analysis by SPSS.

RESULTS

19.7% of women were homozygous for A allele encoding asparagine (N/N), 45.7% were heterozygous (N/S) and 34.6% were homozygous (S/S) for G allele encoding serine. Women heterozygous (N/S) or homozygous (S/S) for serine showed a higher requirement for r-hLH (OR, 95% p-trend = <0.0001) compared to those homozygous for asparagine (N/N). Homozygous G allele was also associated with higher daily and total r-hLH dose per treatment cycle p-trend = <0.0001. Though, the total no of oocytes (14.87 ± 4.95 vs 12.98 ± 5.39 and 13.58 ± 5.45), Gr-I quality embryos (2.61 ± 1.81 vs 2.18 ± 1.96 and 1.98 ± 2.05) were significantly higher in women homozygous for A allele compared to women with heterozygous and homozygous for G allele, clinical pregnancy rates were significantly more in women with for G allele after excluding patients with PCOS and endometriosis conditions (P < 0.04).

CONCLUSION

The present findings reveal that women heterozygous and homozygous for G allele required higher doses of r-hLH supplementation and these women were shown to have higher clinical pregnancy rates.

Clinical Applications of Gonadotropins in the Male

The pituitary gonadotropins, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) play a pivotal role in reproduction. The synthesis and secretion of gonadotropins are regulated by complex interactions among several endocrine, paracrine, and autocrine factors of diverse chemical structure. In men, LH regulates the synthesis of androgens by the Leydig cells, whereas FSH promotes Sertoli cell function and thereby influences spermatogenesis. Gonadotropins are complex molecules composed of two subunits, the α- and β-subunit, that are noncovalently associated. Gonadotropins are decorated with glycans that regulate several functions of the protein including folding, heterodimerization, stability, transport, conformational maturation, efficiency of heterodimer secretion, metabolic fate, interaction with their cognate receptor, and selective activation of signaling pathways. A number of congenital and acquired abnormalities lead to gonadotropin deficiency and hypogonadotropic hypogonadism, a condition amenable to treatment with exogenous gonadotropins. Several natural and recombinant preparations of gonadotropins are currently available for therapeutic purposes. The difference between natural and the currently available recombinant preparations (which are massively produced in Chinese hamster ovary cells for commercial purposes) mainly lies in the abundance of some of the carbohydrates that conform the complex glycans attached to the protein core. Whereas administration of exogenous gonadotropins in patients with isolated congenital hypogonadotropic hypogonadism is a well recognized therapeutic approach, their role in treating men with normogonadotropic idiopathic infertility is still controversial. This chapter concentrates on the main structural and functional features of the gonadotropin hormones and how basic concepts have been translated into the clinical arena to guide therapy for gonadotropin deficit in males.

Polymorphisms in gonadotropin and gonadotropin receptor genes as markers of ovarian reserve and response in in vitro fertilization

Since gonadotropins are the fundamental hormones that control ovarian activity, genetic polymorphisms may alter gonadal responsiveness to glycoproteins; hence they are important regulators of hormone activity at the target level. The establishment of the pool of primordial follicles takes place during fetal life and is mainly under genetic control. Consequently, single nucleotide polymorphisms (SNPs) in gonadotropins and their receptors do not seem to be associated with any significant modification in the endowment of nongrowing follicles in the ovary. Indeed, the age at menopause, a biological characteristic strongly related to ovarian reserve, as well as markers of functional ovarian reserve such as anti-Müllerian hormone and antral follicle count, are not different in women with different genetic variants. Conversely, some polymorphisms in FSH receptor (FSHR) seem to be associated with modifications in ovarian activity. In particular, studies suggest that the Ser680 genotype for FSHR is a factor of relative resistance to FSH stimulation resulting in slightly higher FSH serum levels, thus leading to a prolonged duration of the menstrual cycle. Moreover, some FSHR gene polymorphisms show a positive association with ovarian response to exogenous gonadotropin administration, hence exhibiting some potential for a pharmacogenetic estimation of the FSH dosage in controlled ovarian stimulation. The study of SNPs of the FSHR gene is an interesting field of research that could provide us with new information about the way each woman responds to exogenous gonadotropin administration during ovulation induction.

Suboptimal response to GnRHa long protocol is associated with a common LH polymorphism

The aim of this observational preliminary trial was to estimate the association between the most common polymorphism of LH (LH-β variant: v-βLH), with different profiles of ovarian response to recombinant human FSH (rhFSH). A total of 60 normogonadotrophic patients undergoing a gonadotrophin-releasing hormone analogue long down-regulation protocol followed by stimulation with recombinant human FSH (rhFSH) for IVF/intracytoplasmic sperm injection, and in whom at least five oocytes were retrieved were retrospectively included. On the basis of the total rhFSH consumption, patients were divided into three groups: Group A: 22 women requiring a cumulative dose of rhFSH >3500 IU; Group B: 15 patients requiring 2000-3500 IU; Group C (control): 23 women requiring <2000 IU. The presence of v-βLH was evaluated using specific immunoassays. Peak oestradiol concentrations were significantly lower in Group A when compared with both groups B (P < 0.05) and C (P < 0.001). Group A had a significantly lower (P < 0.05) number of oocytes retrieved (7.3 ± 1.5, 11.7 ± 2.4 and 14.7 ± 4.1 in the three groups, respectively). Seven carriers (31.8%) of v-βLH were found in Group A, whereas only one variant (6.7%) was observed in Group B; no variant was detected in Group C. These preliminary results suggest that v-βLH is more frequent in women with ovarian resistance to rhFSH.