Generation and use of recombinant gonadotropins in fish

Differential Regulation of Gonadotropins as Revealed by Transcriptomes of Distinct LH and FSH Cells of Fish Pituitary

“…The unique expression of their receptors in LH and FSH cells correlates with the accepted role of LH and FSH during the reproductive cycle. Both FSH and LH can increase estradiol secretions, which enhance vitellogenin synthesis, however LH primarily increases DHP secretion that enhances final oocyte maturation and ovulation [ 1 , 61 , 63 ]. Accordingly, esr2 has higher expression in both gonadotropic cells compared to pgr , which might indicate a more fundamental regulation of LH and FSH cells activity by estradiol, and a unique regulation of LH cells by DHP.…”

Recombinant Fsh and Lh therapy for spawning induction of previtellogenic and early spermatogenic arrested teleost, the flathead grey mullet (Mugil cephalus)

“…To this end, different in vivo treatments have been developed, mainly focused on final maturation and spermiation/ovulation stages by single or double rGths injections (Aizen et al, 2017;Kobayashi et al, 2006). However, fish species arrested at the early stages of the reproductive cycle require control of gametogenesis, with long-term treatments of repeated injections that maintain elevated plasma levels of specific Gths (Molés et al, 2020). In the case of males, different successful long-term approaches have been described for immature European eel (Anguilla anguilla) (Peñaranda et al, 2018) and mature Senegalese sole (Solea senegalensis) (Chauvigné et al, 2018(Chauvigné et al, , 2017.…”

“…Hormone therapies based on gonadotropin releasing hormones and luteinizing hormone receptor agonists (human chorionic gonadotropins or pituitary extracts) are commonly used to control the maturation phase, while hormonal control of gametogenesis is rarely used in the aquaculture industry (Mylonas and Zohar, 2007). The use of relatively new recombinant gonadotropin hormones (rGths), the recombinant follicle-stimulating (rFsh) and luteinizing hormones (rLh), can open new strategies in aquaculture to treat reproductive disorders and develop out-of-season breeding programs (Molés et al, 2020). To this end, different in vivo treatments have been developed, mainly focused on final maturation and spermiation/ovulation stages by single or double rGths injections (Aizen et al, 2017;Kobayashi et al, 2006).…”

Differential action of androgen implants on the spermatogenesis of pre-pubertal sea bass exposed to a continuous light regime

“…Of these, Gnrh1 represents the main hypophysiotrophic hormone that elicits the release of Gths, the follicle stimulating hormone (Fsh) and the luteinizing hormone (Lh) to regulate gonadal physiology (Kah et al, 2007;Mazón et al, 2015). Gonadotropins interact with their receptors (Fshr and Lhr) in a highly specific manner in the gonads, although some cross-activation has been reported in several species, thus evidencing that the biological activities of fish gonadotropins seem to be less clearly separated (Kah et al, 2007;Schulz et al, 2010;Molés et al, 2020). Data available on gonadotropin plasma levels from most of the teleost analyzed so far have shown that plasma Fsh levels increase during the early stages of gametogenesis, and then decrease before the final stages of fish gamete maturation and spermiation.…”

“…Data available on gonadotropin plasma levels from most of the teleost analyzed so far have shown that plasma Fsh levels increase during the early stages of gametogenesis, and then decrease before the final stages of fish gamete maturation and spermiation. On the other hand, circulating Lh levels are low or undetectable at the start of gonadal development, and they increase in the final stages of gonadal growth (Schulz et al, 2010;Molés et al, 2020;Mazón et al, 2015). In light of this, piscine Gths have also been shown to be potent steroidogenic hormones.…”