P2.119 Thursday, Jan. 5 The effect of eyestalk neurohormones on circulating glucose and trehalose in two species of oregonid crabs TAMONE, SL*; KELLER, E; LINDEROTH, T; University of Alaska Southeast; University of Alaska Southeast; University of Alaska Southeast email@example.com
Crustaceans rely on carbohydrates for both aerobic and anaerobic metabolism; the primary carbohydrate of importance circulating in the hemolymph is glucose. Glucose is regulated by crustacean hyperglycemic hormone (CHH); a neuropeptide synthesized and secreted from the X-organ sinus gland within the eyestalk. Glucose is stored in arthropod hepatopancreas in the form of glycogen and CHH acts through receptors to stimulate glycogenolysis. In prior studies we determined that glucose circulated at extremely low concentrations when compared to concentrations in vertebrates and other crab species. Another carbohydrate found in arthropods (most notably insects) that serves a metabolic role as well as a cryoprotective role is the disaccharide, trehalose. We measured circulating glucose and trehalose in two species of intact or eyestalk ablated oregonid crabs; Pacific lyre crab (Hyas lyratus) and Tanner crab (Chionoecetes bairdi). Trehalose circulated at significantly higher concentrations in both crab species (186.2 ± 22 and 139 ± 42 µg/ml) in C. bairdi and H. lyratus respectively when compared to glucose (49.7±22 and 15±10 µg/ml) in C. bairdi and H. lyratus respectively. Eyestalk ablation resulted in significantly lower concentrations of both glucose and trehalose after seven days in C. bairdi and this inhibitory effect was eliminated with post ablation injections of CHH containing eyestalk extracts. In H. lyratus, eyestalk ablation resulted in significantly reduced concentrations of trehalose but had no effect on circulating glucose. Injection of eyestalk extracts significantly increased both glucose and trehalose in H. lyratus. This study is aimed at investigating alternative carbohydrates of importance in cold water crustaceans and their potential regulation by eyestalk neuropeptides.