Calcium and other signalling pathways in neuroendocrine regulation of somatotroph functions

Kisspeptin-1 directly stimulates LH and GH secretion from goldfish pituitary cells in a Ca2+-dependent manner

“…In goldfish, mRNA for both sGnRH and cGnRH-II are present in the pituitary and both GnRHs are released from nerve terminals invading the pars distalis [47,48] and GnRH is a major neuroendocrine factor of LH release, as well as an effective stimulator of GH secretion [7][8][9]. In addition, goldfish pituitary glands express Kiss1 mRNA [46].…”

“…We also examined the interactions of gKiss1 10 with the two native goldfish GnRHs, salmon (s)GnRH (goldfish GnRH-3) and chicken (c)GnRH-II (goldfish GnRH-2) [48,49], on LH and GH release; these two GnRHs have been shown to be physiological neuroendocrine stimulators of both LH and GH secretion in this system [4,8,9]. Since Ca 2+ signalling and Ca 2+ entry through voltage-sensitive Ca 2+ channels (VSCCs) are important intracellular events in the neuroendocrine regulation of LH and GH release in goldfish [4,[7][8][9], and Ca 2+ mediates the actions of Kiss1 in many mammalian target tissues [23,28], we also tested the hypothesis that the hormone-releasing effects of gKiss1 10 are dependent on Ca 2+ entry via VSCCs.…”

“…Likewise, the presence of Kiss immunoreactivity and/or mRNA in the pituitary has also been reported for other teleosts, including zebrafish and grass puffer [37,38], suggesting direct pituitary actions of Kiss may be present in other teleosts. Incubation of dispersed goldfish pituitary cells with synthetic goldfish Kiss1 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) (gKiss1 10 ) increased LH and GH released into culture medium by 30 min, as well as elevated LH and GH mRNA levels by 24 h [46]. In contrast, another study indicates that while injection of gKiss1 10 , but not gKiss2 10 , increased serum LH in sexually mature female goldfish, both peptides were ineffective in in vitro 0.5 and 3 h static incubation experiments with goldfish pituitary cells suggesting that gKiss1 did not directly affect pituitary LH secretion [19].…”

Signal transduction mechanisms for autocrine/paracrine regulation of somatolactin-α secretion and synthesis in carp pituitary cells by somatolactin-α and -β

“…In mammals, GH binding to predimerized GHR via site 1 and site 2 interactions (46) leads to JAK2 recruitment and subsequent activation of STAT, MAPK, and IRS/PI3K pathways via the assembly of a multiple-protein signaling complex (6,8). Given that 1) SL receptor has been classified as a member of the GHR1 family (11) and 2) coevolution of structures and functions of homologous ligands and their receptors are known to be a common phenomenon in vertebrate species, e.g., gonadotropins and their receptors (27) and ligandreceptor pairs of vasopressin/oxytocin superfamily (42), the possible involvement of these signaling cascades in SL-induced SL␣ release and synthesis was also examined.…”

Molecular and functional profiling of histamine receptor-mediated calcium ion signals in different cell lines

“…Once they are recognized by their receptors, ligand binding is transduced to the intracellular compartment and results in changing the activity profile of various downstream targets, including enzymes, transcription factors, and ion channels (for reviews, see Refs. [6][7][8][9]). Membrane receptor-mediated signaling often results in transient changes of second messenger concentrations such as 3 0 ,5 0 -cyclic adenosine monophosphate (cAMP), 2 1,4,5-inositol-trisphosphate (IP 3 ), and calcium ions (Ca 2+ ).…”