Activation of insect anti-oxidative mechanisms by mammalian glucagon.
Resembling the main function of insect adipokinetic hormones (AKHs), the vertebrate hormone glucagon mobilizes energy reserves and participates in the control of glucose level in the blood. Considering the similarities, the effect of porcine glucagon was evaluated in an insect model species, the firebug Pyrrhocoris apterus. Using the mouse anti-glucagon antibody, presence of immunoreactive material was demonstrated for the first time in the firebug CNS and gut by ELISA. Mammalian (porcine) glucagon injected into the adult bugs showed no effect on hemolymph lipid level or on the level of AKH in CNS and hemolymph, however, it activated an antioxidant response when oxidative stress was elicited by paraquat, a diquaternary derivative of 4, 4'-bipyridyl. Glucagon elicited the antioxidant response by increasing glutathione and decreasing protein carbonyl levels in hemolymph, decreasing both protein carbonyl and protein nitrotyrosine levels in CNS. Additionally, when co-injected with paraquat, glucagon partially eliminated oxidative stress markers elicited by this redox cycling agent and oxidative stressor. This indicates that glucagon might induce an antioxidant defense in insects, as recently described for AKH. Failure of glucagon to alter AKH level in the bug's body indicates employment of an independent pathway without involving the native AKH.
Alquicer
Glenda
G
Institute of Entomology, Biology Centre, Academy of Science, Branisovská 31, Ceské Budejovice, Czech Republic.
Kodrík
Dalibor
D
Krishnan
Natraj
N
Vecera
Josef
J
Socha
Radomír
R
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001786:Blood Glucose / Q000276:immunology; D002490:Central Nervous System / Q000187:drug effects / Q000276:immunology; D005934:Glucagon / Q000276:immunology / Q000494:pharmacology*; D020062:Heteroptera / Q000187:drug effects* / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects* / Q000276:immunology; D013552:Swine
D000975:Antioxidants; D001786:Blood Glucose; D005934:Glucagon