FSH protein

A recent genome-wide association study (GWAS) of polycystic ovary syndrome (PCOS) in European cohorts has identified six susceptibility loci mapping to 11q22.1 (YAP1), 2p21 (THADA), 11p14.1 (FSHB), 2q34 (ERBB4), 12q21.2 (KRR1), and 5q31.1 (RAD50). The loci of 11q22.1, 2p21 and 11p14.1 have been confirmed to be associated with PCOS in Chinese; whereas the other three new loci (2q34, 12q21.2, and 5q31.1) still need to be evaluated in Chinese. This study was aimed to determine if the three new loci identified in European PCOS also confer risks for PCOS in Han Chinese. We performed a case-control genetic association study comprising 1500 PCOS cases and 1220 age-matched control subjects. Marker SNPs rs1351592 (2q34, ERBB4), rs1275468 (12q21.2, KRR1) and rs13164856 (5q31.1, RAD50) were genotyped using TaqMan-MGB probe assay. Genotyping analysis showed the allele frequency of rs1351592 in gene ERBB4 was significantly different (P = 1.05E-03) between PCOS cases and control group, and remained significant even after BMI adjustment (P-adjusted = 2.09E-04). However, the allele frequencies of the other two risk variants, rs1275468 (12q21.2, KRR1) and rs13164856 (5q31.1, RAD50), were not significantly different in the replication cohort. Our results demonstrate that ERBB4, with the strongest association in European PCOS, also confers risk for PCOS in Han Chinese.

The pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), play essential roles in the regulation of vertebrate reproduction. Activins and inhibins have opposing actions on FSH (but not LH) synthesis, either inducing or inhibiting transcription of the FSH beta subunit gene (Fshb). The translational inhibitor cycloheximide (CHX) produces inhibin-like effects in cultured pituitary cells, selectively suppressing FSH production. Using the murine gonadotrope-like cell line, L beta T2, as a model, we tested the hypothesis that a component of the activin pathway is highly labile in gonadotrope cells and that its rapid loss following CHX treatment impairs activin-stimulated Fshb transcription. Treatment of cells with CHX for 6 h, but not 1 h, blocked activin A-stimulated Fshb transcription. Pre-treatment of L beta T2 cells with CHX for as few as 2-3 h inhibited activin A-stimulated SMAD2/3 phosphorylation without altering total SMAD2/3 protein levels. These data indicated that CHX affects activin signalling upstream of SMAD proteins, most likely at the receptor level. Indeed, CHX rapidly reduced activin A binding to L beta T2 cells. We went on to show that activin A signals via the type II receptor ACVR2, rather than ACVR2B, to regulate Fshb transcription and that the receptor has a half life of similar to 2 h in L beta T2 cells. The mechanism of ACVR2 turnover remains undefined, but appears to be ligand-, proteasome-, and lysosome-independent. Collectively, these data indicate that CHX produces inhibin-like effects in gonadotropes by preventing de novo synthesis of the highly labile ACVR2, thereby blocking activin signaling to the Fshb promoter. (C) 2013 Elsevier Inc. All rights reserved.