Ghrelin effects on midgut tissue antioxidative defense and glutathione S-transferase activity in Lymantria dispar (Lepidoptera)

The aim of the study was to examine changes in Cu‒Zn superoxide dismutase (SOD), catalase (CAT), their gel electrophoresis profiles, glutathione reductase (GR) activity, amount of glutathione (GSH), and the activity of glutathione S-transferase (GST) - phase II biotransformation enzyme in the midgut tissue of gypsy moth (Lymantria dispar L. (Lepidoptera: Lymantriidae)) larvae after ghrelin treatment. Four subpicomolar injections of ghrelin (0.3 pmol) or physiological saline (control) were applied every 24 h. The SOD, CAT, GR, GST activity, and amount of GSH were higher in the ghrelin-treated group than in the control. Electrophoresis gel bands of SOD and CAT had higher area and density in the treated group. The effects of ghrelin on the antioxidative defense and GST activity in insects were detected for the first time. The results provided evidence for possible application of insects as simple model systems in future studies of the role of ghrelin in the antioxidative protection of complex organisms.