Mollusc gonadotropin-releasing hormone directly regulates gonadal functions: A primitive endocrine system controlling reproduction

Characterization of an abalone gonadotropin-releasing hormone and its effect on ovarian cell proliferation

“…Pervious functional studies of GnRH in molluscs have demonstrated a role in reproduction (Nakamura et al, 2007;Osada and Treen, 2013;Treen et al, 2012), but studies in Aplysia suggest that it likely is involved with diverse regulatory functions (Jung et al, 2014;Sun et al, 2012;Tsai et al, 2010). In this study, we show that buserelin and a synthetic HasGnRH peptide exhibit a similar effect on ovary, by stimulating oogonia and early oocyte proliferations.…”

“…Injection of HasGnRH at a relatively high dose (1000 ng/BW) has a relatively low stimulatory effect on cell proliferation compared with the less concentrated doses (500 and 250 ng/BW), suggesting that excessive HasGnRH might down-regulate a receptor, as demonstrated for other hormones (Nuurai et al, 2010). The molecular mechanism of GnRH-mediated gonial cell proliferation may be through gonadal steriodogenesis that in turn promotes cell division (Osada and Treen, 2013;Treen et al, 2012).…”

“…c o m / l o c a t e / a q u a -o n l i n e amidation (King and Millar, 1995). In contrast, GnRH peptides in some invertebrates contain 12 amino acids (Tsai, 2006;Treen et al, 2012). Despite this difference, all GnRHs share a common conserved region at the N-terminus and C-terminus, suggesting that they share a similar function in all animal phyla (Tsai, 2006).…”

“…For example, exogenous GnRH stimulates egg-laying in pond snails (Young et al, 1997) and there is some evidence showing that GnRH is involved in spermatogonial proliferation of the scallop, Patinopecten yessoensiss (Nakamura et al, 2007;Treen et al, 2012). It can also stimulate DNA synthesis in the gonial cells of marine bivalves (Pazos and Mathieu, 1999).…”

Endocannabinoids and Kisspeptins: Two Modulators in Fight for the Regulation of GnRH Activity

“…The involvement of c-fos as well as of estradiol in spermatogonial proliferation has recently been confirmed also in cell lines (He et al, 2008;Sirianni et al, 2008). However, GnRH role in spermatogonial proliferation is an evolutionarily conserved mechanism since it has been demonstrated also in bivalve mollusc (Treen et al, 2012).…”