Putative involvement of crustacean hyperglycemic hormone isoforms in the neuroendocrine mediation of osmoregulation in the crayfishAstacus leptodactylus

Abstract

This study investigates the involvement of eyestalk neuroendocrine factors on osmoregulation in the crayfishAstacus leptodactylus maintained in freshwater. Eyestalk removal was followed by a significant decrease in hemolymph osmolality and Na + concentration and by a 50% increase in mass after one molting cycle.

Different transcription regulation routes are exerted by L- and D-amino acid enantiomers of peptide hormones

“…Yasuda et al (Yasuda et al, 1994) applied the two isomers to in vitro incubated Y-organs, the molting hormone-producing organ, from P. clarkii and noticed about 10-times stronger inhibition of molting hormone synthesis by D-CHH than by the L-isomer. Serrano et al (Serrano et al, 2003) demonstrated that, in P. leptodactylus, a more prominent increase of osmolarity and sodium concentration in the circulation was caused by D-CHH than by L-CHH. Finally, a different time course and intensity of increase in circulating glucose was triggered by the two isomers in P. leptodactylus (Lebaupain et al, 2012;Mosco et al, 2012;Serrano et al, 2003).…”

“…Serrano et al (Serrano et al, 2003) demonstrated that, in P. leptodactylus, a more prominent increase of osmolarity and sodium concentration in the circulation was caused by D-CHH than by L-CHH. Finally, a different time course and intensity of increase in circulating glucose was triggered by the two isomers in P. leptodactylus (Lebaupain et al, 2012;Mosco et al, 2012;Serrano et al, 2003). Earlier hyperglycemia was induced by L-CHH but it lasted for a shorter period and was less intensive than that induced by D-CHH.…”

“…The two enantiomers were simultaneously discovered in Homarus americanus (Soyez et al, 1994) and Procambarus clarkii (Yasuda et al, 1994). Later, they were also identified in other astacids (Aguilar et al, 1995;Bulau et al, 2003;Serrano et al, 2003;Soyez et al, 1997). Each of the two isomers is synthesized in specific Xorgan cells (Soyez et al, 1998) and the L-isomer of H. americanus (Soyez et al, 1997) and Orconectes limosus (Ollivaux and Soyez, 2000) is about three times more abundant than the D-isomer.…”

Roles of crustacean hyperglycaemic hormone in ionic and metabolic homeostasis in the Christmas Island Blue crabDiscoplax celeste

“…In recent years, a variety of other functions for these hormones have been established, involving (for example) inhibition of ecdysteroid (Webster and Keller, 1986;Chang et al, 1990;Chung and Webster, 2003;Chung and Webster, 2005), methyl farnesoate (Liu et al, 1997) and ovarian protein synthesis (Khayat et al, 1998;Avarre et al, 2001). A subject of topical interest is the involvement of CHH in ionoregulatory processes (Charmantier-Daures et al, 1994;Charmantier et al, 1999;Chung et al, 1999;Townsend et al, 2001;Serrano et al, 2003;Chung and Webster, 2006). Whilst it is known that sinus gland extracts cause rapid and reversible changes in transepithelial potentials, and Na + transport in isolated perfused gills of Pachygrapsus marmoratus (Spanings-Pierrot et al, 2000), the precise mechanisms regulated by CHH in crustacean gill tissues remain poorly investigated, despite our extensive knowledge of branchial membrane exchangers and pumps (Lucu, 1990;Onken et al, 1991;Onken and Putzenlechner, 1995;Lucu and Towle, 2003;Weihrauch et al, 2004;Tsai and Lin, 2007;Masui et al, 2008).…”

The adaptive significance of crustacean hyperglycaemic hormone (CHH) in daily and seasonal migratory activities of the Christmas Island red crab Gecarcoidea natalis

“…These include the repression of ecdysteroid synthesis by the Y-organ, and thus a possible involvement in moult control (Webster and Keller, 1986;Chang et al, 1990), the inhibition of reproductive processes via the inhibition of methyl farnesoate synthesis (Liu et al, 1997), and the inhibition of vitellogenin (Vg) mRNA, protein synthesis (Khayat et al, 1998) or Vg gene expression (Tsutsui et al, 2005). An involvement in iono-osmoregulatory processes is also documented (Charmantier-Daures et al, 1994;Chung et al, 1999;Serrano et al, 2003), and it appears that CHH is involved in stimulation of ion transport across respiratory epithelia (SpaningsPierrot et al, 2000) and in dipsogenesis during ecdysis (Chung et al, 1999).…”