The differential secretion of FSH and LH: regulation through genes, feedback and packaging

Impact of the FSHB gene -211G/T polymorphism on male gonadal function

“…We observed that men with the GT genotype and TT genotype had 35 and 54% reduced FSH levels, respectively, compared to those of men with the GG genotype. The strong influence of FSHB -211G/T on serum FSH, seen in this study, confirms observations from previous studies reporting a significant negative association between this SNP and FSH levels, in which serum FSH levels decreased in GT group and TT group carriers of 10-27% and 24-64% respectively, compared to those of the GG group [10,5,7]. These results also confirm that FSH production is genetically determined by the transcription rate of the FSHB gene and that in turn the transcription rate is regulated by the highly conserved promoter regions of the FSHB gene [10] and, in particular, by an 11 bp element, encompassing the -211 nucleotide, which binds to the LHX3 homeodomain transcription factor [7].…”

“…The lower serum LH observed between the T allelecarrier men of this study may suggest additional regulatory effects of FSHB -211 T allele, beyond gonadal development and function, on male hormonal balance and physiology. However, it is necessary to widen the study to increase the number of TT-carrying patients to confirm these data, because previous larger studies reported that serum LH increased with the number of the T allele [5,7]. Grigorova and colleagues detected a negative association between FSHB SNP and serum testosterone (GG > GT > TT) [17], not confirmed by a subsequent study [15].…”

“…The human FSHB gene (MIM 136530;11p13; genomic sequence 4.2 kb), coding for the FSH β-subunit, consists of one non-coding exon plus two translated exons that encode the 129-amino acid preprotein. The mechanisms controlling the transcription of the FSHB gene are critical regulatory steps in the production of the FSH hormone [5][6][7][8]. These mechanisms are complex, involving the actions of tissue-specific and widely expressed transcription factors [9].…”

Mechanisms regulating angiogenesis underlie seasonal control of pituitary function

“…As the blood flows from the brain to the pituitary (11), alterations in the vascular loops of the infundibulum that will give rise to the long portal vessels (12) could contribute not only to regulate the transfer of PT products to the PD, but also to alter the delivery of hypothalamic factors; thus, the increased vascular connections during the long days of summer would be expected to favor increased supply of stimulatory and inhibitory hypothalamic signals to the PD at this time of year. Notwithstanding that, the reduction in vascularity during the short days of winter is likely to play a role in the modulation of the gonadotroph response to GnRH by means of preventing desensitization of GnRH receptors (30) and fine-tuning the differential control of gonadotropin secretion (31,32), which are essential processes to ensure normal fertility.…”

Wild ungulate vontraception: Use of GnRH agonist or GnRH vaccine to control reproduction in captive and free-ranging female elk (Cervus elaphus nelsoni)

“…The gonadotrophs of the anterior pituitary are exquisitely sensitive to small changes in GnRH pulse amplitude and frequency (Belchetz et al 1978). Non-basal luteinizing hormone (LH) release is directly correlated to GnRH pulses (Clarke & Cummins 1982), whereas follicular stimulating hormone (FSH) is less tightly regulated by GnRH and has a significant component which is constitutively derived (McNeilly et al 2003). Gonadotropin releasing hormone signaling can be temporarily suppressed using chronic treatment with continuous, high doses of GnRH agonists.…”